A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A
Acquired Mutations: Due to various causes, gene changes
within individual cells, and accumulate throughout a
person's
lifetime.
Acquired
mutations are also called somatic mutations. (See Germline
Mutation).
Adenocarcinoma: A type of cancer involving the cells from the lining or inner surface of an organ such as the colon. Most cancers of the colon, breast, and lung are adenocarcinomas.
Adenoma: A benign tumor involving cells from the lining or inner surface of an organ, such as the colon. If an adenoma becomes cancerous, it is then called an adenocarcinoma.
Adhesion: Scar tissue attaching abnormally, covering or distorting organs, such as tubes, ovaries, or other internal organs, limiting their movement and possibly causing infertility and pain.
Adjuvant therapy: Treatment provided in addition to the primary treatment. Alternative medicine: Practices not generally recognized by the medical community as standard or conventional medical approaches.
Agonist: A chemical that mimics the biochemical action of another chemical. Agonists often closely resemble naturally occurring substances and cause the same response in a cell that the naturally occurring substance would. The opposite is an antagonist, which blocks the action of an agonist.
Allele: A variant form or version of the same gene. Different alleles produce variations in inherited characteristics, which can be benign or disease-causing. An example of benign allele variations are those that cause different eye colors or blood types.
Alpha-Fetoprotein (AFP): AFP is a protein made by the baby's liver. It is found in the amniotic fluid ans in smaller amounts, in the mother's bloodstream during pregnancy.
Alzheimer's disease: A progressive disease in which nerve cells in the brain
degenerate and brain matter shrinks, resulting in impaired thinking, behavior
and memory. Amenorrhea: The absence of a woman's monthly period.
Amino Acid: Any of a class of 20 molecules that combine to form proteins.
Amniocentesis: A procedure performed in the second trimester of pregnancy, involving the withdrawal of a small amount of amniotic fluid from the sac surrounding the baby for testing.
Amyloid: A starchlike protein (known as a glycoprotein) that is deposited in tissues as a part of a disease process, called amyloidosis.
Amyloidosis: Disease resulting from the deposition of amyloid, a starchlike protein (known as a glycoprotein), in various tissues or organs of the body and impairing their function.
Androgens: A group of hormones that promote the development and maintenance
of male sex characteristics, produced in the adrenal glands and ovaries in
women.
Aneuploidy: One or a few chromosomes above or below the normal chromosome number. In human beings, 23 pairs of chromosomes is the normal chromosome number in each non-reproductive cell. Disease can occur when there are more or less chromosomes than normal, or anueploidy. For example, three copies of chromosome number 21 or trisomy 21 (Down syndrome) is a form of aneuploidy.
Angiogenesis: blood vessel formation or growth. For cancer, it describes the formation of blood vessels between a tumor and the surrounding tissues. This process is necessary in order to keep the tumor alive and to allow it to grow larger.
Antagonist: A substance that acts against and blocks the biochemical
action of a chemical. For example, a drug which binds to a cell receptor without
eliciting the normal biochemical response is an antagonist. Can be used to
prevent an egg from being released prematurely. It is the opposite of an agonist.
Anti-depressants: Medications used to treat depression.
Anti-hypertensive drugs: Medications used to treat high blood pressure.
Anti-inflammatory drugs: Drugs that reduce inflammation (swelling).
Anxiety: A feeling of apprehension, fear, nervousness or dread accompanied
by restlessness or tension.
Apoptosis: A form of cell death in which the cell uses specialized cellular machinery to kill itself. This is a normal cellular process and is necessary for development and health of the body by eliminating old cells, unnecessary cells, and unhealthy cells. Without an orderly process for getting rid of cells, we would double in size within a year. Cancerous cells do not go through apoptosis although they are unhealthy. Apoptosis is also called programmed cell death.
Aromatase: An enzyme involved in the production of estrogen. For women who have gone through menopause, aromatase produces all of the estrogen in the body.
Assisted Reproductive Technologies (ART): A group of therapies that employ manipulation of the egg and or sperm and or early conceptus in order to establish a pregnancy.
Ataxia: A neurologic term describing muscular incoordination often manifesting as an unsteady gait and lack of postural balance.
Atherosclerosis: Also called hardening of the arteries, this is a disease
characterized by a narrowing of the arteries caused by cholesterol-rich plaques.
Atherosclerosis is a common cause of coronary artery disease or heart disease.
Atypical Hyperplasia: An increase in the number of normal cells in a tissue. This has been seen in breast tissue and often leads to a mass, which a physician would biopsy to see if it is benign or malignant. See Factors Contributing to Breast Cancer Risk.
Autosomal Dominant Inheritance: A pattern of inheritance where an alteration in just one copy of a pair of genes causes a detectable trait. Individuals who possess one mutant copy of a gene for a dominant disorder are usually affected. A child conceived by an affected individual has a 50% chance of inheriting the abnormal copy of the gene, and thus the disorder or trait. Dominant disorders do not "skip" generations and most affected individuals have an affected parent.
There are two exceptions to this: 1) a new mutation in a dominant gene can
cause the trait to appear for the first time in a family; 2) a few genes may
have incomplete penetrance, i.e. not everyone who has the gene manifests the
trait. Torsion dystonia is a dominantly inherited condition with reduced penetrance.
Autosomal Recessive Inheritance: A pattern of inheritance where a specific trait is manifest only when both copies of the gene are altered. A disorder is considered recessive when a single fully functional copy of a gene is sufficient to prevent disease.
In order for an individual to have two non-functional copies of a gene, a mutated copy must be inherited from each parent. It is expected that both parents of an affected child are entirely unaffected, even though they both carry an altered copy of the gene; they are called "carriers." When
both partners in a couple are carriers, they have a 25% (1-in-4) chance of
having an affected child with each pregnancy. An example of an autosomal recessive
disease is Tay-Sachs disease.
Autosome: Any of the non-sex-determining chromosomes. Human cells have 22 pairs of autosomes, numbered 1 to 22. (In addition to autosomes, human cells also contain a pair of sex chromosomes - XX in females and XY in males).
Axillary Lymph Node: Lymph nodes that are located in the cavity beneath the junction of the arm and the body (armpit). These lymph nodes are often biopsied in women with breast cancer to look for metastases.
Azoospermia: A condition in which there is a lack of sperm in the semen. Men with this condition often have cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. CFTR mutations can cause Cystic Fibrosis, in which the vast majority of men are infertile.
B
Basal Body Temperature (BBT): The body temperature at rest. It is taken orally each morning immediately upon awakening and recorded on a calendar chart. The readings are studied to help idenify the time of ovulation.
Base: Bases are molecules that are the essential building blocks of DNA and RNA, which in turn make up genes and proteins. There are four bases, often represented as letters that correspond to their chemical names. The code letters for the bases are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine. The sequence of the bases, A, T, G, and C, encode the structure of proteins (and also determine their function).
For a picture:
http://www.genome.gov/Pages/Hyperion//DIR/VIP/Glossary/Illustration/Pdf/dna.pdf
Beta-thalassema: A genetic blood disorder in which there is decreased
production of hemoglobin. Hemoglobin is the protein that carries the oxygen
in the blood to different tissues. People with the disorder have anemia and
sometimes bone deformations. They also may require regular blood transfusions.
Beta-thalassemia is found at a higher incidence in people of Mediterranean
descent.
Biochemical Tests: A group of tests of the placenta or feo-placental function used to predict and thus try to prevent adverse fetal outcomes.
Biofeedback: A method of learning to voluntarily control certain body functions
such as heartbeat, blood pressure, and muscle tension with the help of a special
machine. This method can help control pain.
Biphosphonates: A group of drugs used to treat osteoporosis and the bone pain
caused by some types of cancer.
Birth control: A way for men and women to prevent pregnancy. Methods include
birth control pills, condoms, vaginal spermicides, intrauterine devices (IUDs)
and vasectomy.
Bladder: The sac that holds urine.
Bladder prolapse: A condition in which the bladder moves downward from its
normal position. It is usually caused by a weakness in the pelvic floor after
childbirth.
Blastocyst: An embryo which has developed to a hollow ball of approximately 60-100 cells
after 5 days in culture.
Bloom Syndrome: A disorder which results in poor growth and an increased
susceptibility to infection. There is a high rate of cancer from which individuals
usually die before the age of 30.
Bone Marrow Transplantation: A procedure in which bone marrow is taken
from a healthy donor and transplanted into a patient with deficient bone marrow
function. Bone marrow is found in the soft, fatty tissue inside bones where
blood cells (red blood cells, platelets, and white blood cells) are produced
and developed. Deficient bone marrow function can be a result of chemical treatment
(chemotherapy) or radiation treatment for cancer, as a result of hereditary
blood diseases, or due to the accumulated damage of certain disorders. Healthy
bone marrow may be taken from a patient before he/she undergoes chemotherapy
or radiation treatment (autograft), or may be taken from a donor, especially
in cases of hereditary blood disorders (allograft).
Bone mineral density (BMD): A term used to describe the amount of calcium
present in bone. It can be measured using a special x-ray called a quantitative
computed tomogram.
BRCA1 Breast Cancer Susceptibility Gene: BCRA1, like BRCA 2, is a tumor suppressor gene. This means that it is a gene that normally helps to control cell growth. Women who carry a genetic mutation in BRCA1 have an increased lifetime risk to develop breast cancer, and are at risk to develop it at an earlier age compared to the general population. For more information, see BRCA1.
BRCA2 Breast Cancer Susceptibility Gene: BRCA2, like BRCA1, is a tumor suppressor gene. This means that it is a gene that normally helps to control cell growth. Women who carry a genetic mutation in BRCA2 have an increased lifetime risk to develop breast cancer, and are at risk to develop it at an earlier age compared to the general population. For more information, see BRCA2.
Breast cancer: A disease in which abnormal cells in the breast divide and
multiply in an uncontrolled fashion. The cells can invade nearby tissue and
can spread through the bloodstream and lymphatic system (lymph nodes) to other
parts of the body.
C
CA-125: A blood protein that acts as a tumor marker associated with ovarian cancer. Eighty-five percent of women with clinically diagnosed ovarian cancer have been found to have elevated levels of CA125. Elevated levels of CA-125 have been linked to an increased likelihood of ovarian cancer even when a woman has not been diagnosed with ovarian cancer. HOWEVER, CA125 can also be elevated during the 1st trimester of pregnancy, during menstruation, in the presence of certain noncancerous illnesses, and with the presence of cancer in other tissues of the body. Therefore elevated CA125 levels do not guarantee the presence of ovarian cancer. Another problem with CA125 screening is that some women who have ovarian tumors may not have elevated CA125 levels. IN SUMMARY, CA125 levels are not accurate for detecting either the presence or absence of ovarian cancer.
Calcitonin: Calcitonin is a hormone produced by cells in the thyroid gland
(located in the neck). Calcitonin controls the level of calcium in the blood
and assists the body in absorbing calcium into bones.
Calcium: A mineral taken in through the diet that is essential for a variety
of bodily functions, such as the transmission of nerve impulses, muscle contraction
and proper heart function. Imbalances of calcium can lead to many health problems
and can cause nerve cell death. Calcium is also important for bone health.
Canavan Disease: A disorder characterized by progressive central nervous
system degeneration. Infants appear normal at birth but then begin to lose
skills and degenerate within the first year of life. Death usually occurs within
the first 10-20 years of life.
Cancer: A general disease term for more than 100 diseases for a condition
characterized by uncontrolled, abnormal cell growth. It can involve any part
of the body and can spread either locally or to another site in the body (Metastasis).
Another term for cancer is malignancy.
Carrier: A person who has one mutated copy of a recessive gene and one non-mutated copy. Carriers do not usually develop disease but can pass the mutated gene on to their children. For autosomal recessive traits or diseases, two carriers have a 1-in-4 or 25% chance of having a child with the trait or disease in each pregnancy.
Carrier frequency: The numbers describing how many people in a population are carriers for an autosomal recessive disease. Carriers have a mutation on only one copy of their genes, and are usually unaffected.
Carrier Testing (Screening): Testing to identify individuals who carry one copy (out of two) of a disease-causing recessive gene that could be inherited by their children. Carrier testing is designed for healthy people who have no symptoms of disease, but who are known to be at high risk because of family history or ethnicity. For more information, see Screening.
Cataracts: A cloudy or opaque area in the lens of the eye.
Cell proliferation: An increase in the number of cells as a result of cell
growth and cell division.
Cervical Factor: Infertility due to previous surgery or structural abnormality of the cervix. Also applied when there are factors associated with the cervix which inhibit sperm function.
Cervical Mucus: The secretion of the cervix which changes in volume and consistency throughout the menstrual cycle. Its quality is a reflection of homonal stimulation.
Cervix: The lower section of the uterus which protrudes into the vagina
through which babies pass when they are
born and serves as a reservoir for sperm .
Chemotherapy: Drugs that have a toxic effect on cells. Often used in the treatment
of cancer to kill the cancerous cells.
Chorionic Villus Sampling (CVS): A procedure performed in the first trimester of pregnancy, involving the withdrawal of a small amount of chorionic villi from the placenta for testing.
Chromosomal Abnormalities: An error(s) that occurred when an egg or sperm cell was developing.
Chromosomes: Structures in our cells that carry our genetic information
or genes.
Chromosomal Translocation: A condition where a fragment of one chromosome is broken off and attached to another chromosome.
CHRPE (congenital hypertrophy of the retinal pigment epithelium): Abnormal retinal pigmentation appearing as a "spot" on the eye but which does not interfere with vision. In an individual at risk for Familial Adenomatous Polyposis (FAP), the presence of multiple or bilateral CHRPE may be evidence of a gene mutation.
Clinical trial: An organized research program conducted with patients to evaluate
a new medical treatment, drug or device.
Clone: A genetically identical copy of an organism, gene, or cell resulting from manipulation of the egg in a laboratory. Although an organism can be genetically identical to another organism, the two copies may be very dissimilar based on minute differences in the environment in which they develop. The issues of clones and cloning are highly debated topics in genetics today, although not relevant to our discussion of genetic disorders.
Cloning: The process of making genetically identical copies. A highly debated topic in genetics today, although not relevant to our discussion of genetic disorders.
Colectomy: The surgical removal of all or part of the colon.
Colonoscopy: Examination of the colon through a flexible, lighted instrument called a colonoscope. The colonoscope transmits images of the colon and allows the physician to take tissue samples so they can diagnose irregularities including colon cancer. Colonoscopy lets the physician see the inside of the rectum, colon, and large intestine all the way up to the bottom of the small intestine. See Sigmoidoscopy.
Combined hormone therapy: Estrogen combined with progesterone.
Complementary therapy: Practices not generally recognized by the medical community
as standard or conventional medical approaches and used to enhance or complement
standard treatments. Complementary medicine includes dietary supplements, mega
dose vitamins, herbal preparations, herbal tea, acupuncture, massage therapy,
magnet therapy, spiritual healing and meditation.
Compound Heterozygotes: A person who has two different mutated forms (alleles) of a particular gene. In other words, both copies of the gene are mutated, but each copy has a different mutation.
Congenital: Any trait or condition that is present at birth. The condition or trait usually exists before birth, but can be caused by damage during the birthing process. An example is congenital adrenal hyperplasia, which is a genetic disorder that is present at birth and is characterized by a deficiency of the hormones aldosterone and cortisol and an overproduction of male sex hormones.
Conjugated equine estrogens: Estrogen compounds produced from the urine of
pregnant mares.Brand name is Premarin.
Connexin 26 GJB2: A condition characterized by congenital hearing loss
with no other associated medical complications.
For more information, see Nonsyndromic
Hearing Loss.
Contig (Contiguous) Map: A "map" depicting the order of several small overlapping clones, representing a segment of a chromosome. It is a chromosomal map demonstrating the location of adjacent DNA segments on a chromosome, which can be used to study a very large segment of the genome.
Continuous combined therapy: A low dose of estrogen and a lose dose of progesterone
taken daily.
Coronary artery disease: A condition caused by the narrowing of the arteries
that supply blood to the heart muscle.
Crohn's Disease: This disease is a form of inflammatory bowel disease and it causes inflammation of the gastrointestinal tract, most commonly in the ileum (the last section of the small intestine). Symptoms are intermittent and include abdominal pain, fever, nausea, vomiting, weight loss, and occasionally bloody diarrhea. Crohn's disease can also cause inflammation of the joints, spine, eyes, and liver. It is diagnosed by an Xray or a colonoscopy. Treatment consists of anti-inflammatory drugs and possibly surgery.
Cyclic regimen: Continuous treatment with estrogen combined with a progesterone
for 10-14 days of the month.
Cyst: A closed sac lined by epithelial (skin) tissue and is usually
filled with fluid or semisolid material.
Cystic Fibrosis: An autosomal recessive disease
in which a thick mucus clogs the lungs and blocks the ducts of the pancreas.
It also leads to infertility in males. At this time, the average life span
is 30 years of age. It occurs at a higher incidence in Northern Europeans or
individuals of Northern European ancestry.
Cytogenetics: The study of chromosomes.
D
Dentigerous Cyst: A cyst that contains fluid and one or more imperfect teeth (not fully developed). It occurs in relation to an erupted (grown in) tooth and it may very rarely become malignant.
Depression: A condition characterized by altered mood. There is loss of interest
in pleasurable activities. Depression prevents a person from leading a normal
life. Types of depression include major depression, bipolar depression, chronic
low-grade depression (dysthymia) and seasonal depression (Seasonal Affective
Disorder or SAD).
Desmoid Tumor: A benign tumor that has the characteristics of a ligament and intertwines extensively around surrounding tissues. They may look like dense scar tissue. They are difficult to remove because of their close interaction with surrounding tissue and 70% recur over time.
Diabetes: A group of diseases in which the body cannot properly control the
amount of sugar in the blood. As a result, the level of sugar in the blood
is too high causing a variety of complications ranging from cardiovascular
disease (heart disease) to blindness and kidney failure. This disease occurs
when the body does not produce enough insulin or does not use it properly.
DNA: A molecule that determines the structure, function, and behavior of the cell. It is the substance of heredity and it comprises genes. The characteristics or traits that each person has are due to the interaction of DNA and the environment.
DNA insertion-deletion loop: This DNA structure leads to a DNA copying error. It occurs most frequently in repetitive DNA sequences when the protein copying the DNA may "slip" resulting in more or less bases ordinarily seen in one strand. This leads to a "looping
out of the resultant excess DNA bases.
DNA Mutational Analysis: This type of genetic testing looks at an individual's DNA to determine if there are mutations, or changes, in a specific gene. Individuals who receive testing are trying to determine if a mutated gene will result in production of a non-functional or poorly functional gene product (protein).
DNA Repair Genes: Genes that repair damaged DNA. When these genes are altered, they permit mutations to accumulate in the DNA, which can lead to disease. For example, Fanconi Anemia and Bloom Syndrome are caused by defects in DNA repair genes.
DNA Sequencing: A process that can determine the exact order of the bases in a segment of DNA. This allows for the determination of specific mutations in a gene by comparing changes of the sequence away from the sequence that is expected or is most commonly found.
Dominant Allele: An allele or gene that results in a trait or disease in a person who has only one mutated copy of that gene for the trait, regardless of the counterpart allele on the other chromosome. This is in contrast to a recessive gene in which a trait occurs only when both copies of the gene are nonfunctioning. For more information, see Autosomal Dominant Inheritance. For contrast, see Recessive Allele.
Down Syndrome: A genetic condition caused by the presence of of an
extra copy of chromosome 21 in the cells of the affected individual. Down syndrome is associated with mental retardation, characteristic facial features and othe medical problems, such as heart defects.
DXA scan: Also called dual X-ray absorptiometry scan, it is a special X-ray
that detects bone thinning.
Dysmenorrhea: Pain associated with a woman's menstrual period.
Dyspareunia: Pain during intercourse.
Dystonia: A neurologic condition involving repeated involuntary twisting
and movement of a variety of muscle groups.
E
Encode: Containing coded information, such as the genetic blue print for making a protein, which is represented by a specific sequence of bases in DNA.
Endogamous: The description of a group in which reproduction occurs only within that particular group. Examples of how "endogamous groups" are
defined would be religious groups, social class, or a specific culture.
Endometrium: The lining of the uterus.
Endometrial cancer: Cancer of the lining of the uterus or womb.
Endometriosis: A condition in which tissue that looks and acts like endometrial
tissue is found outside the uterus, usually inside the abdominal cavity.
Enzyme: A protein that facilitates a specific chemical reaction within a cell. Enzymes cause specific chemical changes in other substances without being changed themselves. Examples include the proteins which are necessary to break down (digest) food into smaller molecules that the body can use. A mutation in an enzyme can cause disease. For example, Tay-Sachs disease is caused by a mutation in an enzyme responsible for breaking down a specific type of fat, or lipid. The lipid then accumulates and causes a deterioration of the nervous system, resulting in the symptoms associated with Tay-Sachs disease.
Enzyme Assays: This type of testing measures the activity of a particular
gene product (enzyme), in other words, how well the enzyme does its job. The
level of enzyme activity is then compared to "normal" or "average" levels in
individuals who have two normal copies of the gene. A person who is a carrier
for a recessive disorder has one normal (non-mutated) copy of the gene and
one mutated copy of the gene. Thus, they would be expected to produce about
half the amount of functional product that a non-carrier individual would,
or have 50% of normal enzyme activity. An individual who has two mutated copies
of the gene will have much less gene product than is typically expected. An
individual is not usually affected with symptoms of a disorder until his or
her enzyme activity level is less than 10% of normal.
Epidermoid Cyst: A cyst containing fluid (oil or fatty semisolid material) and epidermal (skin) tissue. It appears as a small, nontender lump on the skin.
Epithelial: From the epithelium, which is the covering of the internal and external structures of the body. An example is the skin covering our bodies or the skin lining the digestive tract.
Estradiol: Produced by the ovaries, the dominant form of estrogen in premenopausal
women.
Estrogen: Estrogen is a female hormone produced by the ovaries. Estrogen
deficiency can lead to osteoporosis . Estrogen stimulates
and maintains female sex characteristics. They are either natural or synthetic.
Estrogens are used to treat menstrual and menopausal disorders and are also
used as oral contraceptives.
Estrogen replacement therapy: The replacement of a woman's declining hormones
with prescription hormone therapy.
Ethics: The study of fundamental principles which define values and
determine moral duty and obligation.
Ethnicity: A person's background or affiliation relating to a large group of people sharing a common and distinct national, racial, religious, linguistic, or cultural heritage. In almost every ethnic, racial, or demographic group, certain genetic diseases occur at higher frequencies among their members than in the general population.
Evista (Raloxifene): A drug that belongs to the family of drugs called selective
estrogen receptor modulators (SERMs) and is used in the prevention and treatment
of osteoporosis in postmenopausal women. Raloxifene is also being studied as
a cancer prevention drug.
Expressivity: The extent to which a genetic disease is expressed or how consistent the expression of a disease is. When there is variable expressivity of a disease, affected individuals may have symptoms ranging from mild to severe, but will always have some symptoms. Expressivity describes the degree of disease manifestation and can be contrasted to Penetrance in which the disease is either present or not (all-or-none expression).
F
Fallopian tube: One of the two Fallopian tubes that transport the egg from the ovary to the uterus (the womb).
False Negative: A test result indicating that a person does not have a mutation or disease when, in reality, they do.
False Positive: A test result indicating that a person has a mutation or disease when, in reality, they do not.
Familial: A trait that is more common in members of a family than in the general population. The trait can be caused by shared genes, shared environment, or both.
Familial Adenomatous Polyposis (FAP): An autosomal dominant condition in which hundreds of potentially cancerous polyps develop
in the colon and rectum, and also sometimes in the stomach, duodenum, and terminal ileum. Polyps usually first appear at puberty and colon cancer is typically diagnosed by age 25. FAP is caused by a mutation in the APC gene.
Familial Cancer: Cancer, or a predisposition toward cancer, that runs in families. See Familial.
Familial Dysautonomia: A disorder caused by the abnormal development
of the sensory and autonomic nervous systems. Common manifestations include
difficulties with swallowing, temperature and blood pressure regulation, and
pain perception.
Fanconi Anemia: A disorder that is characterized by anemia, short stature,
learning disabilities and mental retardation, increased cancer risk, and often
congenital anomalies.
Fetus: The stage of human development from 10 weeks gestation until birth.
Fibrinogen: A protein in the blood that helps it clot.
Fibroids: Common benign tumors,also called a fibroma, made up of muscle cells
and connective tissue that develop within the wall of the uterus.
Fibroma: A benign tumor consisting of fibrous of connective tissue. It is also called a fibroid tumor or a fibroid.
Fimbriae: The finger-like projections on the end of the fallopian tubes. The
fimbriae sweep the egg into the fallopian tube.
First degree relative: A relative who is parent, sibling, or child of an individual. A second degree relative would be an uncle, aunt, grandparent, niece, nephew, or grandchild.
First Trimester Screening: An early non-invasive way to screen for Down syndrome during pregnancy. This involves a blood test and ultrasound examination.
Follicle-stimulating hormone (FSH): A hormone produced by the pituitary gland
(located at the base of the brain). In women, FSH stimulates the growth of
follicles, the small, cysts that hold the eggs and the supporting cells responsible
for the growth and nurturing of the egg. In men, FSH is necessary for sperm
production.
Forteo: An injectable bone-building medication
Fosamax: Also known as alendronate, Fosamax is a drug that has been shown
to increase bone mass and decrease the number of fractures. It is used to prevent
and treat osteoporosis.
Founder Effect: This can occur when a new population is established
by a few original founders, who only carry a small fraction of the total genetic
variation of the original, larger population. If one or more of these founding
members carry a disease mutation, a significant proportion of future descendents
could also carry the disease mutation and the gene frequency would then be
much higher than it was in the population that the settlers came from.
G
Gaucher Disease: A disorder that leads to the progressive accumulation
of a specific lipid or fat in the bone marrow, spleen, and liver. In Type I,
there is no neurologic involvement, while Types II and III have involvement
of the central nervous system.
Gene: The physical unit of inheritance that occupies a specific location on a chromosome. A gene is comprised of DNA, and contains the code for a specific product, usually a protein such as an enzyme. The human genome contains between 30,000 to 35,000 genes.
Gene Deletion: The total loss or absence of a gene, which may lead to disease.
Gene Insertion: The addition of a DNA sequence into a gene that can range in size from a single nucleotide to thousands of nucleotides long. It can disrupt the normal structure and function of the gene that it is inserted into and may cause disease.
Gene Pool: All of the genes in all of the individuals in a breeding population. More precisely, it is the collective genotype of a population.
Gene Product: The biochemical material, either RNA or protein, that results from the expression of a gene. The amount of gene product is a measure of gene activity and abnormal amounts can be correlated with disease-causing alleles.
Gene Testing: The analysis of a sample of blood, or other tissue for genetic (DNA) markers that indicate the presence or absence of genetic disease.
Gene Therapy: Treating disease by replacing, manipulating, or supplementing
nonfunctional genes with functional genes. An example would be the early studies
of gene therapy for cancer in which researchers were trying to improve the
body's natural ability to fight the disease or to make tumors more sensitive
to other kinds of therapy. Gene therapy to correct a hereditary disease may
involve the addition of a functional gene or group of genes to a cell by gene
insertion.
Genetic: Inherited; anything that has to do with information that is passed from parents to children through DNA in the genes.
Genetic Disorder: A condition resulting from an alteration, or mutation in one or both copies of a specific gene, resulting in disease symptoms.
Genetic Counseling: The educational process that helps individuals,
couples, or families to understand genetic information and issues that may
have an impact on them. It often deals with the determination of a genetic
diagnosis in a person and/or the recurrence risks within that same generation
or the next generation.
Genetic Drift: Genetic drift happens due to random changes in how often a gene appears in a population. This may explain why certain characteristics are more common among certain groups of people.
More technically, this can be explained as a change in the frequency of a gene, resulting from its transmission (by chance), to a higher or lower frequency than predicted. Genetic drift occurs most rapidly in small populations. In contrast, in large populations, random deviations in allele frequencies (how often a particular allele is seen) in one direction are more likely to be cancelled out by random changes in the opposite direction.
Genetics: The scientific study of heredity, or how particular qualities, traits, or genes are transmitted from parents to offspring.
Genetic Predisposition: When a person who has an inherited gene mutation has a greater risk than the general population of developing a disease associated with the mutation. For example, gene mutations in BRCA1 or BRCA2 can predispose a person to breast cancer, although they will not necessarily develop breast cancer.
Genetic Screening: Testing groups of individuals to identify defective genes capable of causing hereditary conditions. Genetic screening is used to refer to two different processes: 1) Testing individuals to see if they have a genetic trait or disease, and 2) Testing individuals to determine if they carry genes that could result in a genetic disorder in their children. Often referred to as population-based screening. For more information, see Genetic Testing.
Genetic Testing: Essentially the same as genetic screening because both use the same procedures. Often, the difference between testing and screening involves why an individual is being tested. Screening usually applies to an individual member of a group, while testing applies only to an individual. For example, an individual with a family history for (or family member with) a certain disease who suspects they may be a carrier would undergo genetic "testing."
Genome: All the genetic material in all of the chromosomes of a particular organism.
Genome Maps: Charts that indicate the ordered arrangement of the genes or other DNA markers within the chromosomes.
Genotype: The actual genes that encode for the characteristics seen in an individual, or the genetic make-up of an individual. This is in contrast to the phenotype, which describes the physical characteristics of an individual.
Germ Cells: The reproductive cells of the body, either the egg or sperm cells.
Germline Mutation: A genetic change in the body's reproductive cells (eggs or sperm) that, after fertilization, becomes incorporated in the DNA of every cell in the body; also called a hereditary mutation. (See Acquired Mutations.)
Gestation: The period of development in a fetus from the time of fertilization to birth. For humans, the entire gestation period is typically nine months long.
Granulocytes: A type of white blood cell in the immune system that destroys microorganisms.
Gynecologist: A doctor who specializes in the care and health of the female
reproductive organs.
H
Hamartoma: A growth that looks like a tumor but is disorganized and is benign.
Haplotypes: The representation of a set of adjacent or closely linked alleles on one chromosome.
HCG (human Chorionic Gonadotropin): A hormone that is produced by the developing placenta when a woman becomes pregnant. Levels increase over the first trimester and then begin to decline. Average levels over the course of the pregnancy have been calculated and are used in triple marker screening, which involves analysis of a blood sample from a pregnant woman. If the measured amount of hCG in a pregnant woman is very different than expected, it might indicate the presence of an abnormality in the fetus, such as Down Syndrome, Trisomy 18, or a neural tube defect. However, measurements of hCG levels during pregnancy are NOT diagnostic of fetal abnormality.
HDL cholesterol: Referred to as "good" cholesterol, high-density
lipoprotein is a type of cholesterol that protects against heart disease.
Hemizygous: When there is only one copy of a gene or group of genes in a cell, instead of the more typcial two. Males with the typical number of chromosomes are hemizygous for all genes on the X chromosome because they have only one copy of the X chromosome.
Hepatic: Referring to the liver.
Hepatosplenomegaly: Enlargement of the liver and spleen.
Heart disease: A condition that affects the heart muscle or the blood vessels
of the heart.
Hereditary Mutation: See Germline Mutation.
Hereditary Nonpolyposis Colorectal Cancer (HNPCC): A hereditary cancer predisposition syndrome caused by one of the genes involved in DNA repair (mismatch repair). It presents predominantly with early onset colon cancer but can also lead to endometrial (uterine) cancer and other cancers. It is estimated to account for 5% of all colorectal cancers.
Heredity: The transmission of a gene from a parent to a child.
Heterogeneity: When identical or similar diseases or symptoms are caused by different mutations in different genes. A general example of this is Hereditary non-polyposis colorectal cancer (HNPCC), a dominantly inherited cancer predisposition syndrome which can be caused by mutations in any one of several different genes.
Heterozygous: When the two alleles, or versions of a gene, at a single locus are different. A person who is heterozygous for an autosomal recessive disorder, (such as Tay-Sachs) with one fully functional copy and one non-functioning copy, is called a carrier and is unaffected with the disorder.
Heterozygote: A person possessing two different forms of a particular gene, at a single locus. A person who is a heterozygote for a gene associated with an autosomal recessive disorder has one functional copy of the gene and one nonfunctional copy. They would be called a carrier and would be unaffected.
Heterozygote Advantage: In certain specific environments, an individual
who has one mutated copy of a gene may be healthier or more resistant to disease
than either an individual who has two non-mutated copies of the same gene or
an individual who has two mutated copies of the gene. This person can also
be described as being heterozygous for the recessive mutation and an unaffected
carrier. An example of this is an increased resistance to malaria in females
who carry the gene for G6PD deficiency. This is important in areas of the world
with a high incidence of malaria, and accounts for the higher-than-expected
number of disease mutations. This is suggested as the reason that a high number
of carriers have been maintained in the population for certain medically serious
or lethal recessive disorders, instead of seeing a decrease of the mutation
over time.
Homozygous: Having two identical versions of the same gene, one on each chromosome. In autosomal recessive disorders a person who is homozygous for a mutation will manifest the disease (be affected) while a heterozygote will not.
Hormone: A chemical substance produced in the body that controls and
regulates the activity of certain cells or organs.
Hormone therapy (HT): The use of hormones, usually a combination of estrogen
and progesterone, as a therapy, often used to treat the discomforts of menopause
or to replace hormones (especially estrogen) lost after menopause.
Hot flashes: A sudden wave of mild or intense body heat caused by rushes
of hormonal changes resulting from decreased levels of estrogen. Hot flashes
can occur at any time and may last from a few seconds to a half-hour. They
are due to blood vessel opening and constricting and a symptom of menopause.
Human Genome: The full collection of genes needed to produce a human being.
Human Genome Project: An international research effort (led in the United States by the National Institutes of Health and the Department of Energy) aimed at fully understanding the human genome.
Hyperplasia: A condition in which there is an abnormal increase in the number of normal cells in a tissue or organ.
Hysterectomy: Surgical removal of the uterus.
I
Impotence: The inability to have an erection adequate for sexual intercourse.
Incontinence: Loss of bladder and/or bowel control.
Induced menopause: Menopause that occurs when the ovaries are surgically removed.
Induced menopause can also result from damage to the ovaries caused by radiation
or by medications used in chemotherapy.
Inflammatory Bowel Disease: A general term describing a chronic intestinal disease resulting in inflammation of the bowel, and either the large or small intestine. Two main subtypes exist and they are ulcerative colitis and Crohn's disease. Symptoms include abdominal pain and diarrhea and these symptoms can be intermittent. It can occur at any age but most commonly occurs in young adults. Treatment involves medications and sometimes surgery.
Informed Consent: The communication between a patient and a health care provider about a procedure such as genetic tests. The patient is given information about the risks and benefits of genetic testing along with a description of the process and possible outcomes. The patient is then given an opportunity to ask questions and when the patient fully understands the information, the patient is asked to explicitly give consent for the testing to be performed. This allows the patient to exercise control over his or her medical care, and helps protect the health care provider from liability issues.
Inheritance: Transmission of genes from parents to offspring.
Inhibited sexual desire (reduced libido): A decrease in desire for or interest
in sexual activity.
Insomnia: Difficulty in going to sleep or getting enough sleep.
J
Jansky's Classification: The classification of human blood groups
now designated as O, A, B, and AB.
K
Karyotype: The images of a set of stained chromosomes arranged in order from largest to smallest. On a karyotype, it is possible to see large scale duplications or deletions of genetic material. For example, Trisomy 21 (Down Syndrome) or Monosomy X (Turner Syndrome) can be seen on a karyotype.
Kegel exercises: Exercises to strengthen the muscles that line the floor of
the pelvis by alternately squeezing and holding the muscles and then relaxing
them. They can help prevent incontinence.
Knudson's "Two-hit" Hypothesis: A theory proposing that individuals who inherit a mutation in a tumor suppressor gene are more likely to develop cancer and at an earlier age than someone in the general population. The theory proposes that hereditary cancer occurs via a multi-step pathway that begins with the inactivation of both copies of a tumor suppressor gene ("two-hits"). The "first hit" is an inherited mutation of a tumor suppressor gene, resulting in two different forms of the same gene within one cell (heterozygosity). The "second hit," a mutation in the other copy of the tumor suppressor gene, then needs to occur before there is progression to cancer. The second hit results in two non-working copies of the tumor suppressor gene, and the resulting absence of the working copies contributes to the development of a tumor or abnormal growth.
Because an individual with an inherited mutation has a mutated copy of the gene in every cell, they are more likely to develop two mutations than someone who has to have a mutation first occur in a cell ("first hit") and then have a second mutation occur in the other copy of the same tumor suppressor gene in the same cell ("second hit"). For the same reason, cancer is more likely to occur at an earlier age in an individual with an inherited (or germ line) mutation in a tumor suppressor gene.
L
Last Menstrual Period (LMP): A convention used for dating pregnancies in which day one is designated to be the first day of a woman's last menstrual period. This is done to compensate for the often unknown conecption date. By this method, the embryological age of the fetus is typically two weeks younger than the date determined from the LMP.
LDL cholesterol: Considered to be "bad" cholesterol, low-density
lipoprotein is a type of cholesterol that increases the risk of heart disease.
Linkage Analysis: Tracing the inheritance of a gene or trait in family members by studying traits that are co-inherited ("linked") with that gene or trait.
Locus: The specific place on a chromosome that a gene occupies; the location of a gene.
Luteinizing hormone (LH): A hormone produced by the pituitary gland (located
at the base of the brain). In women, LH causes the dominant follicle to release
its egg from the ovary (ovulation). In men, LH stimulates the production of
testosterone, which is necessary for sperm production.
Lymph Node: One of numerous bean shaped bodies containing lymphocytes, arranged along the lymphatic system. The lymph node is an integral part of the immune system. It is also one of the most common sites for breast cancer metastases and lymph nodes in the region of lymphatic drainage from the breast are often removed and examined for metastasis at the time of breast cancer surgery.
M
Macular degeneration: A disease that occurs when the macula, the part of the
retina at the back of the eye that provides sharp, central vision, deteriorates
with age. It is a leading cause of vision loss in the elderly.
Male menopause: Subtle changes in the function of the testis that may occur
as early as 45 to 50 years of age, and more dramatically after the age of
70.
Mammogram:A series of specialized X-rays of the breast used to detect abnormal
growths or changes in the breast tissue. Currently, mammograms are considered
routine health management for women over the age of 50, and may also be helpful
for women between the ages of 40 and 50.
Mammography: A screening process in which an X-ray is taken of the breasts. Mammography is used to detect breast cancer early, when lumps are less than 2 cm or smaller in size, and cannot be felt during physical examination. Currently, mammograms are considered routine health management for women over the age of 50, and may also be helpful for women between the ages of 40 and 50. Mammograms are not normally performed on women younger than 40 years, unless there is a clinical indication for it.
Manifesting Heterozygote: A female who manifests signs or symptoms
of an x-linked recessive condition that ordinarily is only evident in males.
Maternal Age Effect: As a woman gets older, the chance of nondisjunction occurring during the formation of an egg increases. Nondisjunction results in the egg having an extra chromosome or a missing chromosome, which results in birth defects or miscarriage.
Meconium Ileus: Obstruction of the intestine (ileus) by compacted, overly thick meconium, which is the medical term for a newborn's first stools. Meconium ileus is a condition found in some babies with Cystic Fibrosis due to poor exocrine gland function and lack of digestive enzymes that normally break down meconium.
Mendelian Disorder: A disorder caused by a single gene defect, which can occur in either dominant or recessive inheritance patterns. The inheritance of these disorders follows the ratios first described by Gregor Mendel. A disorder that is not Mendelian would be one where the disorder was due to environmental causes or due to a combination of factors, also called Multifactorial Inheritance.
Mendelian Inheritance: A description of the inheritance of genes and traits from parents to their children, as first described by Gregor Mendel. See Mendelian Disorder.
Meningitis: Inflammation of the meninges, or the membranes that cover the brain and spinal cord.
Mastectomy: A general term for an operation in which breast tissue is removed. The operation may be a total mastectomy in which the entire breast is removed or a partial mastectomy in which only a part of the breast is removed. Axiallary lymph nodes may or may not also be removed during the surgery to look for metastases.
Maternal Serum Alpha Fetoprotein (MSAFP): A substance that is produced by the liver of the fetus, excreted into the amniotic fluid, and is then absorbed into the bloodstream of the mother. A blood sample can be taken from the mother and the level of MSAFP can be measured. The level increases gradually until late in pregnancy. The expected levels of this substance are known at specific times in pregnancy and variations from these amounts can indicate the presence of a problem in the fetus, such as a neural tube defect, Trisomy 18, or Down Syndrome. However, measurements of MSAFP levels during pregnancy are NOT diagnostic of fetal abnormality.
Menarche: The onset of menstruation, synonymous with female puberty.
Menopause: The complete cessation of menstruation, often occurring near age 50. Menopause is the opposite of the menarche. See the entire definition of Menopause
Menopause symptoms: the symptoms that a woman experiences due to loss of estrogen
at the time of menopause. Hot flashes, night sweats and associated sleep disturbances,
and vaginal dryness are menopause symptoms.
Menopause transition:A woman can usually tell if she is approaching
menopause because her menstrual periods starts changing. The medical terms
used to describe this time are the "menopause transition" and "perimenopause".
Menstrual: Pertaining to menstruation (the menses), as in last menstrual period, menstrual cramps, menstrual cycle, and premenstrual syndrome. From the Latin menstrualis, from mensis meaning month.
Menstrual cycle: The monthly cycle of changes in the ovaries and the lining of the uterus (endometrium), starting with the preparation of an egg for fertilization. When the follicle of the prepared egg in the ovary breaks, it is released for fertilization and ovulation occurs. Unless pregnancy occurs, the cycle ends with the shedding of part of the endometrium, which is menstruation. Although it is actually the end of the physical cycle, the first day of menstrual bleeding is designated as "day 1" of the menstrual cycle in medical parlance.
Menstruation: The periodic shedding of the uterine lining.
Metabolic Disorder: A disorder in which there is abnormality in any of the biochemical reactions that take place in the body. A metabolic disorder may affect the way food is digested, energy is produced, growth, cognitive function, and/or the elimination of waste.
Metachronous tumors: multiple separate tumors in the same tissue diagnosed within an interval greater than 6 months of each other.
Metastasis: The process by which cancer spreads from the primary site of the tumor to form another tumor at another site in the body. Cells that metastasize are still of the primary cell type. For example, breast cancer can metastasize to the liver; the cancerous cells in the liver tumor are breast cell descendents. This is important because breast cancer cells may be treated very differently than liver cancer cells.
Microsatellite Instability: Microsatellites are repeating DNA units of 2-4 nucleotides that are found throughout the genome. The repeats can be of various lengths, which means that there can be a variable number of 2-4 nucleotides repeated in a row in the DNA sequence. The number of repeats can increase or decrease during DNA replication and repair, a process described as "instability." If this occurs in a gene, it can lead to disruption of the normal functioning of the gene, and disease. For example, this is often seen in Hereditary Nonpolyposis Colorectal Cancer.
Mitochondrial Disorder: A group of neuromuscular diseases caused by damage to the mitochondria-small, energy-producing structures found in every cell in the body that serve as the cells' "power plants." Mitochondrial myopathies include Kearns-Sayre syndrome, myoclonus epilepsy, and mitochondrial encephalomyopathy.
Mittelschmerz: The pelvic pain that some women experience during ovulation.
(Ovulation generally occurs about mid way between menstrual cycles; hence the
term mittelschmerz, which comes from the German words for "middle" and "pain.")
Mucolipidosis IV: A disorder that causes central nervous system deterioration,
usually within the first year of life. Symptoms of the disease are mild motor
and mental retardation that slowly, progresses. Overall prognosis and estimated
life span are not known..
Multifactorial Disorder: The result from the mutation in multiple genes, often coupled with environmental causes, for example, heart disorder, diabetes and cancer.
Multifactorial Inheritance: The inheritance pattern in which a trait or disease results from a combination of genetic factors and possibly some environmental influence. Many common traits are multifactorially inherited. Examples of this type of inheritance are skin coloring (melanocyte production determined by genes and sun exposure), Type 2 diabetes (predisposing genes and eating habits), and height (genes and food intake). For contrast, see Mendelian Inheritance.
Mutation: A process by which genes undergo a structural change. It can be a change in the size, arrangement, or molecular sequence of a gene. A mutation may not cause physical problems, for example a benign mutation that causes blue eyes or Type O blood, or a mutation may also be disease causing, such as mutations that cause Tay-Sachs disease.
N
Neural Tube Defects: A birth defect caused by abnormal development
of the neural tube, which is a structure that forms the head, neck and spine
of the baby.
Newborn screening: Examination of blood samples from a newborn infant to detect biochemical changes due to disease. Each state determines which disorders are included in its newborn screen. For information on this tests for each state, link to http://genes-r-us.uthscsa.edu.
Niemann-Pick Disease, Type A: A condition characterized by severe neurodegeneration
beginning in infancy. Affected babies often have hepatosplenomegaly (enlarged
liver and spleen), poor growth, and deterioration of physical and mental processes.
Death usually occurs before 5 years of age.
Night sweats: Severe hot flashes which occur at night and result in a drenching sweat. Night sweats can have many different causes including medications, infections, and cancers.
Non-classical Adrenal Hyperplasia: A disorder caused by an incomplete
block in the pathway to convert cholesterol to cortisol. This block results
in an overproduction of androgens, such as testosterone, and causes severe
acne, excess facial and body hair, short stature, insulin resistance, menstrual
problems, and reduced fertility in females. It does NOT cause female babies
to have ambiguous or male genitals at birth and it is not life threatening
(due to salt wasting), which are seen in congenital adrenal hyperplasia.
Nondisjunction: A condition in which chromosomes in a pair fail to separate during the process of cell division. When this occurs during the making of an egg or sperm cell, it can result in an egg or sperm with one too few or one too many chromosomes. For example, if this occurred such that a sperm had 24 chromosomes instead of 23, the embryo would have 47 chromosomes (after fertilizing an egg with 23 chromosomes), instead of 46. Down Syndrome is an example of a disorder resulting from having an extra chromosome (47 chromosomes) and Turner Syndrome is an example of a disorder resulting from having one less chromosome (45 chromsomes).
Non-Syndromic Hearing Loss: See Connexin 26 GJB2.
Nucleotide: One of the structural components making up DNA and RNA. A nucleotide consists of a base (one of four chemicals: adenine, thymine, guanine, and cytosine), a molecule of sugar, and a molecule of phosphoric acid.
Nucleus: A structure within a cell that houses the chromosomes (and the DNA that makes up the chromosomes). The nucleus is surrounded by a membrane, and it is the site where DNA replication and RNA synthesis take place.
Null Allele: An allele (or version of a gene) that has a mutation resulting in no functional protein production at all. This is in contrast to a mutation that still allows for some functional protein to be made.
Nulliparity: Never having been pregnant.
O
Odontomas: A tumor that differentiates and develops into tooth structures.
Oncogenes: Genes that normally regulate the growth of cells but, when overexpressed or mutated, can lose this control and foster the growth of cancer.
Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis . There is always an onset to a disease but never to the return to good health. The default setting is good health.
Oocytes (ova or egg cells): The female cells of reproduction.
Oophorectomy: A surgical procedure in which one or both of the ovaries is removed.
Oophorectomy: A general term for an operation to remove one or both ovaries.
Orgasm: Sexual climax.
Osteoporosis: Thinning of the bones with reduction in bone mass due
to depletion of calcium and bone protein. Osteoporosis predisposes a person
to fractures, which are often slow to heal and heal poorly. It is more common
in older adults, particularly post-menopausal women; in patients on steroids;
and in those who take steroidal drugs. Unchecked osteoporosis can lead to changes
in posture, physical abnormality (particularly the form of hunched back known
colloquially as "dowager's hump"), and decreased mobility.
Ovarian cancer: An abnormal growth of tissue (tumor) that develops in a woman's
ovaries.
Ovarian cyst: A sac filled with fluid or a semisolid material that forms on
or within one of the ovaries, the small organs in the pelvis that make female
hormones and hold egg cells.
Ovary:The female gonad, the ovary is one of a pair of reproductive glands in women. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries produce eggs (ova) and female hormones. During each monthly menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a fallopian tube to the uterus. The ovaries are the main source of female hormones, which control the development of female body characteristics, such as the breasts, body shape, and body hair. They also regulate the menstrual cycle and pregnancy.
P
Pap smear: A screening test in which a sample of cells is taken from a woman's
cervix. The test is used to detect changes in the cells of the cervix.
Parathyroid hormone: A substance made by the parathyroid gland (located in
the neck) that helps the body store and use calcium.
Parental Age Effect: The phenomenon of increasing liklihood of having a child with a chromosome or genetic disorder as one, or both, of the parents get older. Advanced maternal age is considered to be 35 years at the time of delivery. Older women are more likely to produce egg cells with an extra chromosome, for example, which can lead to Down Syndrome or other chromosomal syndromes. Advanced paternal age, leading to an increase in incidence of certain autosomal dominant disorders such as Torsion Dystonia, is considered to be 45-50 years.
Pedigree: A family tree diagram often used to trace the heredity of a particular trait or disease through many generations of a family.
Pelvic cavity: The space inside the pelvis that holds the reproductive organs.
Pelvic examination: An examination during which a doctor inserts a speculum
(an instrument that lets the doctor see inside the vagina) and examines the
vagina, cervix and uterus. The doctor will feel for any lumps or changes.
A Pap smear test is usually done during a pelvic exam.
Pelvic ultrasound: A test that uses sound waves to produce an electronic image
of the organs of the pelvis, especially the ovaries.
Penetrance: The likelihood that a given abnormal gene will actually result in disease, most often associated with dominant disorders. A highly penetrant disorder is one in which the majority of individuals who have the mutated gene will develop the disorder. A less than fully penetrant disorder might be one in which only a percentage of mutation carriers will ever develop the disorder. Contrast with
Expressivity.
Percutaneous Umbilical Blood Sampling (PUBS): A prenatal diagnosis method that uses the blood from the umbilical cord for a rapid chromosome analysis or other testing, often within 48 hours after blood is drawn. It involves the insertion of a needle through the pregnant mother's abdomen, like amniocentesis, to draw a blood sample from a vein in the umbilical cord. PUBS is performed at about 18 weeks gestation or later and may be recommended if a physician feels that an ultrasound, amniocentesis, or chorionic villus sampling do not provide enough information about the fetus. It might also be performed to test for certain infections and blood disorders. If a baby is suspected to be anemic, PUBS is the only way to confirm this, and it allows for transfusion while the needle is in place. The procedure is also known as umbilical vein sampling, fetal blood sampling, and cordocentesis. The miscarriage risk is about 2%. For other types of prenatal diagnosis, see Amniocentesis, Chorionic Villus Sampling, Ultrasound, and Preimplantation Genetic Diagnosis
Pericarditis: Inflammation of the pericardium, or the lining around the heart.
Perimenopause: The menopause transition. Perimenopause begins about 6 years before the natural menopause. This is a time when the levels of hormones produced by the aging ovaries fluctuate leading to irregular menstrual patterns (irregularity in the length of the period, the time between periods, and the level of flow) and hot flashes (a sudden warm feeling with blushing). Other changes associated with the perimenopause and menopause include night sweats, mood swings, vaginal dryness, fluctuations in sexual desire (libido), forgetfulness, trouble sleeping and fatigue, probably from loss of sleep.
Peritonitis: Inflammation of the peritoneum, or the lining of the abdomen.
Phenotype: Observable characteristics of an organism produced by the organism's genotype (the specific genes possessed by an organism) interacting with the environment.
Physical Maps: DNA maps showing the location of identifiable landmarks, either genes or distinctive short sequences of DNA. The lowest resolution physical map shows the banding pattern on the 24 different chromosomes; the highest resolution map depicts the complete nucleotide sequence of the chromosomes. (See Contig Map).
Phytoestrogens: Estrogen-like substances from certain plants that work like
a weak form of estrogen.
Placenta: Tissue connecting the mother and baby that provides nourishment to the baby during pregnancy.
Polygenic: When multiple genes are involved. This often refers to the phenotype that occurs due to the interaction of multiple genes, such as height or heart disease.
Polyp: A growth, most often benign, that develops on the inside wall of a hollow organ, such as in the colon.
Population Screening: Testing individuals in a specific population,
who are at greater risk for being carriers
for genes that could cause specific genetic disorders.
Postmenopausal: After the menopause . Postmenopausal is defined formally as the time after which a woman has experienced twelve (12) consecutive months of amenorrhea (lack of menstruation) without a period.
Postmenopause: The period of time after the menopause . The postmenopause is formally defined as the time after which a woman has experienced twelve (12) consecutive months of amenorrhea (lack of menstruation) without a period.
Postnatal: After a baby is born.
Precancerous Polyps: Protruding growths in the colon or large intestine that are benign but have the potential to become cancerous. The classic polyp has a stalk with a bulb-shape on the end of it.
Predispositional Gene Tests: Tests to identify gene abnormalities that may make a person susceptible to certain diseases or disorders. An example of this is BRCA1 and BRCA2 testing for susceptibility to breast and ovarian cancer. See Overview of BRCA1 and BRCA2 for more details.
Predisposition gene: A gene that increases the likelihood for an individual to develop a disease when it is mutated. Genetic testing for a predisposition gene only changes the likelihood for an individual to develop for a disorder. For example:
- If a gene mutation is found, an individual is more likely but not guaranteed to develop the disease
- If a gene mutation is not found that is known to cause the disease in a family, the individual with the negative test is not guaranteed to not develop the disorder but is instead only less likely to do so.
Examples of predisposition genes are
BRCA1 and BRCA2.
Predictive gene: A gene that when they are mutated are known to cause disease. An example of this type of gene is the Huntington gene associated with Huntington's disease.
Preimplantation Genetic Diagnosis: A prenatal diagnosis method that involves testing the egg/embryo
for a genetic disorder at a very early stage of development. This requires the use of assisted reproductive
technology (ART) techniques, which allow for access to the egg and early embryo. The egg can be screened via
first and second polar body biopsy. After fertilization, the 8-cell stage embryo can be biopsied by the
removal of one or in some cases 2 cells. This is possible without damaging the future development of the
embryo. In other words, the remaining cells are still capable of the same development seen in an undisturbed
embryo. The removed cell(s) can then be analyzed by chromosomal and/or genetic DNA analysis.
For other types of prenatal diagnosis, see Amniocentesis, Chorionic Villus Sampling, Ultrasound, and Percutaneous Umbilical Blood Sampling.
Premature menopause or "premature ovarian insufficiency": Menopause
that occurs before the age of 40 that may be the result of genetics, autoimmune
disorders or medical procedures.
Premature ovarian failure: A condition in which a woman's ovaries, for unknown
reasons, stop producing eggs before the age of 40.
Premenopause: The one or two years immediately before menopause. It can also
refer to the whole of the reproductive period prior to menopause.
Prenatal: Before a baby is born.
Prenatal Screening: Examining the genetic makeup of the embryo or fetus to detect birth defects or genetic disorders before a baby is born. Testing methods include Chorionic Villus Sampling, Amniocentesis, Percutaneous Umbilical Blood Sampling, and Ultrasound. Ultrasound only detects visible signs of birth defects. It is the only screening test listed here that has no associated miscarriage risk. The other screening methods listed look directly at the fetus's DNA, gene products, or metabolites and have a small miscarriage risk due to the invasiveness of the procedure. Any of these tests might be recommended if there is history of genetic disorders in the family, if the mother is over age 34, or if there are any problems detected on an earlier ultrasound.
Prenatal Diagnosis: Examining fetal cells taken from the amniotic fluid, the chorion (embryonic form of the placenta) or umbilical cord blood for biochemical, chromosomal, or gene alterations.
Primary Tumor: Either the first tumor or a tumor at the original cancer site. This is in contrast to a Secondary Tumor, which is a tumor arising at a different location from where it originated due to metastasis.
Progesterone: A female hormone and the principal progestational hormone that is made mainly by the corpus luteum in the ovary and by the placenta. Progesterone prepares the lining (endometrium) of the uterus (the womb) to receive and sustain the fertilized egg and so permits pregnancy. Similarly refers to synthetic versions of the hormone. Also known as progestational hormone.
Progestin: A synthetic compound that produces effects similar to those of progesterone.
Progestogen: Any hormone having the same effect as progesterone in the body;
refers to both natural progesterone and synthetic progesterone.
Prophylactic: Describing a preventive measure, something done to prevent something else from occurring. For example, a prophylactic mastectomy is the removal of breast tissue before the formation of a cancerous tumor in order to try to prevent breast cancer from occurring
Prophylactic Surgery: Surgery to remove tissue that is in danger of becoming
cancerous, before cancer has developed. An example is a prophylactic mastectomy,
which is removal of the breasts of women at high risk of developing breast
cancer.
Prophylactic Surgery: Surgery to remove tissue that is in danger of becoming cancerous, before cancer has developed. An example is a prophylactic mastectomy, which is removal of the breasts of women at high risk of developing breast cancer.
Protein: A large, complex molecule composed of amino acids. The sequence of the amino acids (and the function of the protein) is determined by the sequence of the base pairs in the gene that encodes it. Proteins are essential to the structure, function, and regulation of the body. Examples include hormones, enzymes, and antibodies.
Proteome: All of the proteins expressed by the genome.
Proteomic marker profile: A group of protein markers that may be used for clinical diagnostic, prognostic, or treatment purposes. This approach is currently being used for ovarian cancer research. By looking at changes in the proteomic marker profile, researchers may be able to provide information about whose cancer will stay in remission and whose will recur.
Proteomics: A field of research involving the study of the proteins produced by the human body (the proteome). One of the research topics of proteomics is the association of a protein product with a disease. Researchers do this by looking at the altered levels of protein between individuals with and without the same disease. It enables correlations to be drawn between the range of proteins produced by a cell or tissue and the initiation or progression of a disease state. This may further allow for the discovery of new protein markers for diagnostic purposes and drug treatments.
Q
Quantitative Genetics: The formal study of measureble genetic traits.
Traditionally but not necessarily confined to galtonian
genetics.
R
Recessive Allele: An allele that is expressed only if both copies are mutated or if it is the only copy present. For more information, see Autosomal Recessive Inheritance. For contrast, see Dominant Allele.
Reduced libido (inhibited sexual desire): A decrease in desire for or interest
in sexual activity.
Reproductive Cells: Egg and sperm cells. Each mature reproductive cell carries a single set of 23 chromosomes.
Risk Factor: A characteristic that increases an individual's chance of developing a disease. For example, smoking is a risk factor for lung and other cancers.
RNA: A chemical similar to DNA. The several classes of RNA molecules play important roles in protein synthesis and other cell activities.
S
Salpingo-oophorectomy: Surgical removal of the Fallopian tube and the ovary, usually done bilaterally (on both sides) if it is a prophylactic surgery
Screening: Looking for evidence of a particular disease, such as cancer, in persons with no symptoms of disease. For more information, see Predictive Screening, Prenatal Screening, Carrier Screening, and Population Screening.
Secondary Tumor: A tumor arising at a distant site from its origin, due to metastasis. See Primary Tumor for a contrast.
Selective Estrogen-Receptor Modulator (SERM): A class of drugs that have some of the same biochemical activity as estrogen and are often used to treat breast cancer. An example of a SERM is raloxifene. Like estrogen, raloxifene prevents bone loss and lowers serum cholesterol. However, unlike estrogen, it does not stimulate the division of cells in the lining of the endometrium and thus does not increase the risk of endometrial cancer.
Sensitivity: A measure for assessing the results of a diagnostic or screening
test. It can be thought of as the probability that a person with a disease
will have a positive test result, or as the percentage of people who test positive
for a disease that truly have that disease.
SERM: Selective estrogen receptor modulator is a drug that acts like estrogen
on some tissues but blocks the effect of estrogen on other tissues. Tamoxifen
(Nolvadex) and Evista are two examples of SERMs.
Sexual health: Sexual health refers to the many factors that impact sexual
function and reproduction. These factors include a variety of physical, mental
and emotional issues. Disorders that affect any of these factors can impact
a person's physical and emotional health, as well as his or her relationships
and self-image.
Sexual response cycle: The sequence of physical and emotional changes that
occur as a person becomes sexually aroused and participates in sexually stimulating
activities, including intercourse and masturbation. The sexual response cycle
has four phases: excitement, plateau, orgasm and resolution.
Sexually transmitted disease (STD): A disease passed from one person to another
by unprotected sexual contact. You can get a sexually transmitted disease from
sexual activity that involves the mouth, anus or vagina.
Sigmoidoscopy: A procedure
for examining the lower one third of the colon. It is less invasive than a colonoscopy,
but does not visualize the entire colon. A flexible, lighted tube is inserted
into the rectum and colon, permitting the examiner to see the inside of the
rectum and sigmoid colon. Physicians may use this procedure to find the cause
of diarrhea, abdominal pain, or constipation. When it is used to look for early
signs of cancer in the colon and rectum, it is often combined with additional
tests so as to not miss signs of cancer existing only in the upper parts of
the colon where it does not reach. The discovery of a polyp or other signs
of cancer by sigmoidoscopy (or other tests) indicates the need for a complete
colonoscopy. See Colonoscopy.
Single base-pair mismatch: The pairing of DNA bases in which a mismatch has occurred. DNA bases ordinarily pair up with an adenosine (A) base binding to a thymidine (T) base and a cytosine (C) base binding to a guanine (G) base.
Spina Bifida: See Neural Tube Defect.
Stem Cells: Cells that are unspecialized and have the ability to grow into any type of cell found in the body. These cells have the ability to divide throughout life and produce highly specialized cells to take the place of cells that die. This allows for the repair and replacement of damaged tissue.
Sensitivity: A measure for assessing the results of a diagnostic or screening test. It can be thought of as the probability that a person with a disease will have a positive test result, or as the percentage of people who test positive for a disease that truly have that disease.
Sex Chromosomes: Chromosomes that determine the sex of an organism. In humans, the chromosomes that designate the sex of an individual are the 23rd pair of chromosomes: females usually have two X chromosomes and males have one X and one Y chromosome.
Sickle-Cell Anemia: A serious, inherited disease in which a defect in hemoglobin, the oxygen-carrying pigment in the blood, causes distortion (sickling) of the red blood cell and anemia (not enough red blood cells), which can produce damage to organs throughout the body.
Splenectomy: Surgery to remove the spleen.
Somatic Cells: All of the cells of the body except the reproductive cells.
Somatic Mutations: See Acquired mutations.
Specificity: A measure for assessing the results of a diagnostic or screening test. It can be thought of as the probability that a test will be negative in a person free of a disease, or as the percentage of people who test negative for a disease who are truly negative for that disease.
Sperm: The male reproductive cells.
Stress incontinence: An involuntary loss of urine that occurs during activities
such as coughing, sneezing, laughing or exercising.
Surgical menopause: Induced menopause that results from surgical removal of
the ovaries for medical reasons. Surgical menopause can occur at any age.
Synchronous tumors: This term describes tumors in the same tissue diagnosed within 6 months of each other.
Synovitis: Inflammation of the synovial membrane, or the lining of the joints.
T
Tamoxifen: An anticancer drug that belongs to the family of drugs called antiestrogens.
Tamoxifen blocks the effects of the hormone estrogen in the body. It is used
to prevent or delay the return of breast cancer or to control its spread.
Tay-Sachs Disease: A disorder in which infants have normal development
until approximately 6 months of age, at which time they present with an excessive
startle response, a cherry red spot on the retina, and mild motor weakness.
There is progressive neurodegeneration and death usually occurs by 3-5 years
of age.
Tay-Sachs disease, late-onset: A form of Tay-Sachs disease that does
not show onset until 10 years of age or later. It is often less severe and
has a slower progression than classical Tay-Sachs disease.
Testicles (testes; singular testis): Part of the male reproductive system,
the testicles manufacture the male hormones, including testosterone, and produce
sperm, the male reproductive cells. The testicles are located inside the scrotum,
the loose sac of skin that hangs below the penis.
Testosterone: The male hormone that is essential for sperm production and the
development of male characteristics, including muscle mass and strength, fat
distribution, bone mass and sex drive.
Thyroid gland: A gland located beneath the voice box in the throat that produces
thyroid hormone. The thyroid helps regulate growth and metabolism.
Translocation: The relocation of a chromosomal segment to a different position within the genome. A chromosomal configuration in which part of a chromosome becomes attached to a different chromosome.
Transvaginal ultrasound: This is a method for imaging the genital tract in women to look for any abnormalities of the reproductive tract. A hand-held probe is inserted into the vagina and high-frequency soundwaves are bounced off the internal body structures to create a picture. This type of imaging is used in endometrial and ovarian cancer screening.
Triple Marker Screening: A screening test offered to pregnant women between 15-18 weeks gestation (length of pregnancy) that can detect an increased risk for certain abnormalities in the fetus such as Down Syndrome, Trisomy 18, and neural tube defects. It involves analyzing a blood sample from a pregnant woman and presents no risks to the fetus. It measures three substances: MSAFP (maternal serum alpha-fetoprotein), hCG (human chorionic gonadotropin), and uE3 (unconjugate estriol).
Trisomy: The presence of three copies of any specific chromosome instead of the normal two copies. An example is Trisomy 21, or Down Syndrome, in which there are three copies of chromosome 21 instead of two.
Trisomy 18: The presence of three copies of part or all of chromosome 18. This results in profound mental retardation, distinct facial features, feet malformations, heart malformations, and kidney malformations. This condition rarely allows for survival to birth and of those who survive to be born, greater than 95% do not live past their first birthday. This condition occurs in approximately 1 in 5000 liveborn babies.
Trisomy 21: See Down Syndrome.
Tumor Suppressor: A gene that normally limits the growth of cells. When a tumor suppressor gene is mutated, it may allow cancer to develop. Examples of tumor suppressor genes are BRCA1 and BRCA2.
U
uE3 (uncongugated estriol): The hormone estriol, which is produced by the ovaries and in large amounts by the placenta during pregnancy. Levels typically increase during the second trimester. uE3 is one of three markers, in addition to MSAFP and hCG, which is used to calculate the likelihood of a fetal abnormality such as Down Syndrome, Trisomy 18, or a neural tube defect. However, measurements of uE3 levels during pregnancy are NOT diagnostic of fetal abnormality.
Ulcer: A site-specific area of tissue damage or erosion produced by the sloughing away of inflammatory necrotic (dead) tissue.
Ulcerative Colitis: This disease is a form of inflammatory bowel disease and it causes inflammation of the large intestine (colon). Symptoms are intermittent rectal bleeding, abdominal pain (cramps), and diarrhea. It is diagnosed by tissue biopsy done after the colon is visualized by a sigmoidoscopy or colonoscopy. The cause of ulcerative colitis is unclear but patients with long-standing cases are known to be at an increased risk for colon cancer. Treatment consists of medications and possibly surgery.
Ultrasound: A prenatal screening method that uses high frequency sound waves bounced off tissues to create images on a video monitor. This non-invasive technique is used to examine tissues and is widely used during pregnancy to screen for structural defects in the fetus. There is no evidence of any danger from ultrasound during pregnancy and it is regarded as a highly effective and useful tool for screening procedures. For other types of prenatal diagnosis, see Amniocentesis, Chorionic Villus Sampling, Percutaneous Umbilical Blood Sampling, and Preimplantation Genetic Diagnosis.
Unopposed estrogen: Estrogen taken without a progestogen.
Urge incontinence: A condition characterized by a strong desire to urinate,
followed by involuntary contractions of the bladder.
Urinary tract infection (UTI): A condition that occurs when bacteria from outside
the body gets into the urinary tract and causes infection and inflammation.
Urologist: A doctor who is specially trained to treat problems of the male
and female urinary system and the male sex organs.
Uterus: The small, hollow, pear-shaped organ in a woman's pelvis. This is the
organ in which a fetus develops. Also called the womb.
V
Vagina: The tube that joins the cervix (the lower part of uterus, or womb)
to the outside of the body. It is also known as the birth canal.
Vaginal dryness: Inadequate lubrication of the vagina that can be caused by
low estrogen levels, medication or lack of sexual arousal.
Vaginal lubricant: A moisturizing product used to treat vaginal dryness.
Very-low-dose birth control: Birth control pills that contain less estrogen
than regular birth control pills.
Vitamin D: A vitamin that enables the body to absorb calcium.
Variable Expressivity: See Expressivity.
W
Weight-bearing exercise: Exercise during which bones and muscles work against
the force of gravity and the feet and legs carry a person's weight. Examples
include walking, jogging and dancing.
Wild Type: A genetic term referring to the normal, non-mutated version of a gene.
Women's health specialist: A physician specializing in women's hormonal health
issues.
X
X Chromosome: A sex chromosome; normal human females carry two X chromosomes, and normal human males have one X chromosome.
X-Linked: Genes found on the X chromosome. A male who inherits a mutation
on an X chromosome will manifest the disease because he has no second copy
of the gene to produce functioning protein product.
X-ray: High-energy radiation used in low doses to diagnose diseases and used
in high doses to treat cancer. X-rays use high-energy radiation in low doses
to create images of the body to help diagnose diseases and determine the extent
of injuries.
Y
Y Chromosome: A sex chromosome found only in males; normal human males carry one Y and one X chromosome.
Yeast infections: Infections of the vagina caused by one of the many species
of fungus called Candida. A change in the chemical balance in the vagina allows
the fungus to grow too rapidly and cause symptoms.
Z
Zygote: A concept in which the egg and sperm genetic material (pronuclei) have united.
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