Prenatal Genetic Testing
What is prenatal genetic testing?
Prenatal genetic testing gives parents-to-be information about whether their fetus has certain genetic disorders.
What are genetic disorders?
Genetic disorders are caused by changes in a person’s genes or chromosomes. Aneuploidy is a condition in which there are missing or extra chromosomes. In a trisomy, there is an extra chromosome. In a monosomy, a chromosome is missing. Inherited disorders are caused by changes in genes called mutations. Inherited disorders include sickle cell disease, cystic fibrosis, Tay-Sachs disease, and many others. In most cases, both parents must carry the same gene to have an affected child.
What are the two main types of prenatal genetic tests?
There are two types of prenatal tests for genetic disorders: Prenatal screening tests: These tests can tell you the chances that your fetus has an aneuploidy and a few other disorders. This FAQ focuses on these tests. Prenatal diagnostic tests: These tests can tell you whether your fetus actually has certain disorders. These tests are done on cells from the fetus or placenta obtained through amniocentesis or chorionic villis sampling (CVS).