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GDSP Glossary of Selected Medical Terminology

AFP (alpha-fetoprotein) -- A protein produced by the developing fetus.

Amino Acid -- The basic unit of proteins. The human body makes some amino acids, while others, called essential amino acids, are obtained only from foods containing protein.

Amino Acid Disorders - The amino acid hereditary disorders are the result of defects either in the breakdown of amino acids or in the body’s ability to get the amino acids into cells. The undesired intermediates get build up in the blood and are toxic to the brain causing mental retardation if not detected and treated in early days of newborn age. See Also Organic Acid disorders, or Fatty Acid Disorders

Amniocentesis -- This is a diagnostic test that involves removal of some of the amniotic fluid which contains fetal cells. Used to diagnose chromosome abnormalities.

Anemia -- Any condition where the amount of red blood cells and/or hemoglobin is less than normal. This can impair the blood's ability to deliver sufficient amounts of oxygen throughout the body.

Anencephaly -- A fatal defect in which the top of the neural tube fails to close (see NTD) and the brain does not develop properly.

Antibody -- An immunoglobulin which is present in the blood serum naturally or may develop as a result of an antigenic stimulus (such as a foreign cellular material). It attaches itself to these specific foreign substances, alerting the body to their presence.

Biotinidase Deficiency (BD) -- Individuals with BD have an inactive biotinidase enzyme that cannot release biotin so it can be recycled. Biotin, a vitamin cofactor, is necessary for organic acid metabolism. Untreated BD may lead to severe metabolic decompensation in the newborn period.  Affected children may exhibit seizures, hypotonia, ataxia, developmental delays, vision problems, hearing loss, skin rashes and/or other cutaneous abnormalities. If left untreated, BD can lead to mental retardation and death.

Carrier -- A condition where an individual carries a particular non-working recessive gene but also has a working copy as well. This working gene usually prevents the manifestation of symptoms of the disease that the non-working gene causes. Individuals who are carriers can pass either the working or non-working gene (also referred to as a "trait") to their offspring with equal chance.

Cerebral Palsy -- A congenital condition of muscular weakness and difficulty in coordinating voluntary movement owing to developmental or congenital damage to the brain.

Chelation -- therapy to remove excess iron which builds up in the blood of frequent transfusion recipients.

Chorionic Villus Sampling (CVS) -- A test to obtain cells from the developing placenta. Done early in pregnancy, between 10 and 12 weeks.

Chromosome -- Structures found in the nucleus of a cell, which contain genes. Chromosomes come in pairs, one inherited from each parent, and a normal human cell contains 46 chromosomes, 22 pairs of autosomes (non-sex chromosomes) and two sex chromosomes (either XX or XY).

Cleft Palate -- A congenital defect of the palate in which a longitudinal fissure extends into one or both nostrils.

Congenital -- Characterizing a condition present or existing at birth.

Cystic Fibrosis -- Cystic fibrosis is an autosomal recessive disease requiring a mutation on each of the two copies of chromosome inherited from our parents. CF can cause damage to a number of different body organs, including the lungs and upper respiratory tract, gastrointestinal tract, pancreas, liver, sweat glands, and genitourinary tract.

Detection -- The ability of a testing method or screening program to actually identify individuals with the particular disease or condition. The higher the detection rate, the more accurate the testing method or screening program.

Diagnosis/Diagnostic -- The determination of the existence and nature of a disease or condition.

Dimeric Inhibin-A -- Dimeric Inhibin-A is a protein produced by the ovaries and fetal placenta. Also referred to as Inhibin.

Down Syndrome (Trisomy 21) -- A congenital condition causing mental retardation and unique physical characteristics. Caused by an extra chromosome number 21.

Encephalocele -- A neural tube defect affecting the skull, in which cerebral tissue protrudes through an opening in the skull.

Fatty Acid Disorders -- are genetic metabolic diseases in which the body is unable to breakdown fatty acids to make energy because an enzyme is either missing or not working correctly. When the main source of energy from glucose runs out, the fat is not broken down into energy to be readily available to the newborn causing fatty acid disorders. See Also Organic Acid disorders, or Amino Acid Disorders

Folate -- A type of B vitamin found in enriched bread cereals, beans, leafy green vegetables and citrus fruits which can help prevent certain birth defects, such as NTDs.

Folate Receptor -- A membrane protein which is involved in the cellular uptake of folate.

Galactosemia -- An inherited metabolic disorder caused by a deficiency in the transferase enzyme. This deficiency disrupts the metabolism of galactose, causing mental retardation and other medical problems. Dietary restriction of galactose can reduce the severity of these problems.

Gastroschisis -- A birth defect in which an opening in the abdominal wall allows the intestines to protrude.

Gene -- The functional unit of heredity that carries the instructions needed to create an enzyme or other protein. Genes are organized into structures called chromosomes which are located in the nucleus of each cell.

Genetic -- Influenced or produced by genes. Relating to the branch of science concerned with heredity.

Hemoglobin -- A respiratory protein contained in red blood cells that transports oxygen from the lungs to the tissues of the body. Its structure consists of two pairs of globin (alpha and beta) chains and a heme (iron) group that binds the oxygen.

Hemoglobinopathy (Hemoglobin Disorder) -- A condition caused by a defect in the genetic code for hemoglobin synthesis. This defect affects the amount or the quality of the hemoglobin being produced. Sickle cell anemia is the most common hemoglobinopathy in California. Other common hemoglobin disorders include hemoglobin SC disease and S-beta thalassemia.

Hypothyroidism (Primary Congenital Hypothyroidism) -- A condition characterized by insufficient thyroid hormone (T4 or thyroxine), which may lead to delayed growth and mental retardation. Treatment consists of administering a thyroid tablet daily, which prevents the onset of these symptoms.

Immunoglobulin -- A structural protein consisting of two pairs of polypeptide chains. Variations of these chains allow different types of antibodies to be formed by the body.

Maternal PKU -- A genetic condition in which the high levels of phenylalanine during pregnancy in women with PKU can put their newborns at an increased risk for mental retardation, low birth weight, and birth defects. Women with PKU who are planning pregnancy can reduce or eliminate these health problems in their babies by returning to a phenylalanine-restricted diet.

Metabolic -- Relating to metabolism (chemical changes occurring in the various tissues of the body).

Neural Tube Defect (NTD) -- A defect of the spine or head caused by the incomplete closure of the neural tube in prenatal development.

Organic Acid Disorders -- are a group of inherited metabolic conditions associated with a specific enzyme deficiency that causes the accumulation of organic acids in blood. The accumulated compound or their metabolites are toxic resulting clinical features of these disorders. Organic acid disorders are autosomal recessive and most of them cause neurological damages. See Also Fatty Acid disorders, or Amino Acid Disorders.

Phenylalanine -- A common essential amino acid found in protein-containing foods.

Phenylketonuria (PKU) -- An inherited metabolic disorder in which there is a deficiency or the absence of the enzyme phenylalanine hydroxylase. This enzyme deficiency leads to high levels of the amino acid phenylalanine and low levels of tyrosine, causing mental retardation and other health problems. Dietary restriction of phenylalanine can reduce or eliminate these problems.

Prenatal Diagnosis -- Procedures and tests which diagnose birth defects before the baby is born.

Quad Marker -- A prenatal genetic screening test which estimates the risk for neural tube defects, trisomy21 (Down syndrome), trisomy18 and SLOS.

Renal Agenesis -- Absence of one or both kidneys.

Rh Hemolytic Disease -- A disease affecting newborns that can occur when the Rh blood type in a woman's blood is negative and the baby's Rh is positive. If the mother has developed antibodies against the baby's blood (usually during a previous pregnancy), the fetus can have severe health problems including serious anemia, heart failure, damage to the brain, or death.

Screening Program -- A program in which a large population is tested for a particular disease or disorder in a cost-effective manner with the purpose of identifying those individuals at high enough risk to warrant follow-up diagnostic tests. (California's Newborn Screening Program tests all babies for four congenital disorders so that those with the condition can be identified and treated promptly, thereby preventing mental retardation or other serious disabilities.) Screening programs can identify most, but not all, individuals with any of the disorders for which they screen.

Sickle Cell -- A red blood cell that has undergone an irregular structural change, sometimes appearing like a sickle in shape. This can occur during physical and psychological stress in individuals who have a sickling hemoglobin disorder such as sickle cell anemia.

SLOS -- A very rare birth defect in which the fetus cannot make cholesterol normally.

Spina Bifida -- A birth defect in which the neural tube fails to close during fetal development (NTD) and a portion of the spinal cord and nerves fails to develop properly.

Tay-Sachs -- An inherited, fatal disease which causes nervous system destruction in infancy.

Thalassemia -- A condition caused by a defect that affects the amount of hemoglobin produced. It is characterized by a reduction in or absence of the alpha (alpha-thalassemia) and/or beta (beta-thalassemia) globin chains that make up the hemoglobin molecule.

Thyroxine (T4, Thyroxin) -- The major thyroid hormone found in the thyroid gland and blood. Produced and secreted by the thyroid gland.

Trait -- see Carrier.

Triple Marker -- A prenatal genetic screening test which estimates the risk for neural tube defects, trisomy21 (Down syndrome), trisomy18, and SLOS.

Trisomy 13 -- A congenital condition causing severe mental retardation and death before birth or in early infancy. Caused by an extra chromosome number 13.

Trisomy 18 -- A congenital condition causing severe mental retardation and often death before age 1. Caused by an extra chromosome number 18.

Trisomy 21 -- Same as Down syndrome.

TSH -- Thyroid Stimulating Hormone. It is secreted by the pituitary as a response to low T4 (thyroxine) levels in the blood.

Tyrosine -- An alpha-amino acid present in most proteins.

Ultrasound -- A diagnostic imaging technique utilizing reflected high-frequency sound waves to measure or examine the fetus.


Last modified on: 1/12/2009 4:03 PM