Genetic Carrier Screening (Cystic Fibrosis and Tay-Sachs)
Cystic fibrosis (CF) affects vital organs in the body, especially the lungs and digestive system, clogging them with a sticky mucus that makes it difficult to breathe and digest food.
The abnormal gene that causes cystic fibrosis was discovered in 1989. If both parents are carriers of this gene, there is a one-in-four chance with every pregnancy that their child will have cystic fibrosis. We are now able to determine whether the mother or father carries the gene for CF. Cystic fibrosis is more common in Caucasians, so offering carrier testing is becoming the standard of care in pregnancy for Caucasians and others with a family history of CF. Preconception testing is also available. A screening test for the genetic mutation responsible for Tay-Sachs disease has also been developed. This condition is more common in Jewish people of Eastern European and Russian (Ashkenazi) origin. (About 1 out of every 3,600 babies born to Ashkenazi Jewish couples will have the disease.) Tay-Sachs is also more common among certain French-Canadian and Cajun families.
Laboratory testing in pregnancy has become a critical part of prenatal care. Through this type of investigation, preexisting conditions and those related to the pregnancy can be revealed and managed. Health-care providers should inform their pregnant patients about recommended tests as well as the rationale for such testing, when the results will be available and, if any results are abnormal, what to expect in terms of follow-up. Don't hesitate to ask your doctor, midwife or nurse about the tests you can expect at each of your prenatal visits.