Amniocentesis: A genetic procedure in pregnancy in which amniotic fluid is collected from the amniotic sac. Amniocentesis is performed between 14 and 18 weeks of pregnancy.
Autosomal Recessive Disorder: A disorder caused by mutations in both copies of the same gene. Mutations resulting in an autosomal recessive disorder are inherited from both parents who are carriers.
Carriers: Individuals who have a genetic mutation in one copy of a gene. One gene is normal and the other copy is abnormal. They do not have symptoms because they still have one working normal gene, which is sufficient to keep them healthy.
Chorionic Villus Sampling (CVS): A procedure in which a piece of tissue is collected from the placenta. CVS is usually performed between 10-14 weeks of pregnancy.
Chromosomes: There are 23 pairs of chromosomes, which contain the genes. The first 22 pairs are the autosomal chromosomes and are assigned numbers 1-22. The 23rd pair are called the sex chromosomes (X and Y) because they determine whether an individual is male (XY) or female (XX).
Genes: Units of genetic material (DNA) that are passed down from parents and determine how a body functions and develops.
Genetic Mutation: A change in DNA.
In-vitroFertilization: Assisted reproductive technology in which an egg is fertilized outside a female's body.
Prenatal Diagnosis: Testing for the presence of a genetic condition, as well as other abnormalities, in the fetus during pregnancy.