Genetic Tests to Consider Before Getting Pregnant |
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 There are now tests to detect genetic carriers for dozens of hereditary conditions.The specific tests your doctor recommends for you before you get pregnant will depend on your own personal and family history. Here, Michael Watson, Ph.D., executive director of the American College of Medical Genetics and an adjunct professor of pediatrics at Washington University School of Medicine in St. Louis, lists some of the major genetic conditions your doctor or a genetic counselor may discuss with you at a preconception medical checkup. Canavan Disease What it is: Canavan disease appears in infancy and causes the brain to degenerate due to the imperfect development of the myelin sheath, which covers the brain’s nerve fibers. The condition may cause mental retardation and motor-skill impairment, among other problems. The test: A DNA test. Typically, cells are swabbed from the inside of the cheek for testing. Who may need the test: Those of eastern Ashkenazi (European Jewish) descent. Cystic Fibrosis What it is: A lung disorder in which a thick, sticky mucus clogs airways, leading to infections and possibly gastrointestinal problems. The test: A DNA test (see above). Who may need the test: Caucasians and Ashkenazi Jews. The American College of Medical Genetics and ACOG suggest that all Caucasians considering pregnancy ask their doctor about cystic fibrosis carrier screening. One in twenty-five American Caucasians are carriers and about 1 in 2,500 Caucasian babies are affected. Down Syndrome What it is: A form of mental retardation, linked to a chromosomal abnormality (most commonly an extra chromosome). The test: A chromosome analysis, ideally of a blood sample taken from an affected family member, which enables the lab to determine which type of chromosomal abnormality is responsible. Who may need the test: Those with a family history of Down syndrome or any form of mental retardation. If you have a family history of the most common form of Down’s, you have about a 1-2 percent chance of having a child with the condition, Watson says. With other varieties the chances may even be higher. Tay-Sachs What it is: People with Tay-Sachs disease are missing a chemical needed for brain functioning. The disease causes retardation, blindness, seizures and death (usually before age 7). The test: An enzyme analysis (blood test) or a DNA test (cheek swab); many doctors do both, which gives a better detection rate than either test alone. Who may need the test: Those of French Canadian or Ashkenazi descent. Thalassemia What it is: Thalassemia causes anemia, and can lead to liver and heart problems. People with thalassemia may become dependent on blood transfusions. The test: A blood test that evaluates hemoglobin and red blood cell size. Who may need the test: Those of Asian (alpha-thalassemia) or Mediterranean (beta-thalassemia) descent. A version of this article originally appeared in the Spring 2005 issue of Conceive Magazine. Related Topics: Boost Fertility; Fertility Health |
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