Genetic Counselors Can Help Hopeful Parents Have Healthy Children
Genetic Counseling and Healthy Pregnancy
By simply paying Pat Ward a visit before conception, couples hoping to get pregnant can save themselves and their future children a lot of unnecessary suffering.
Ward, a genetic counselor at Baylor College of Medicine in Houston, helps eager couples determine what potential diseases they may see in their offspring.
"We look at both family histories, as well as the results of genetics tests we can do here in the lab, to determine risk," she said. "I help them decide what the best course of action is for their particular case."
For example, one form of testing and counseling deals with cystic fibrosis.
Cystic fibrosis or CF is a genetic disease affecting approximately 30,000 children and adults in the United States. Ward and the BCM genetics lab can test for CF without drawing blood; all that is needed is a swab inside the cheek.
"It is painless and inexpensive, and when you compare it to what you could be avoiding, the test is a very smart choice," said Della Olvera of BCM Medical Genetics Laboratory.
More than 10 million Americans are unknowing carriers of the defective CF gene. An individual must inherit two defective CF genes - one from each parent - to have CF. Every time two carriers conceive, there is a 25 percent chance that their child will have CF; a 50 percent chance that the child will be a carrier of the CF gene; and a 25 percent chance that the child will be a non-carrier.
"Once we determine that risk, I can let them know their options," Ward said. "In some cases that might be using donated sperm, prenatal testing, or pre-implantation diagnosis," she said.
Pre-implantation diagnosis is commonly practiced by BCM assisted reproduction. "With this procedure, we can avoid cystic fibrosis by choosing the embryos that are unaffected by the defective gene, and implanting them in the uterus," said Dr. John Buster, director of the BCM Division of Reproductive Endocrinology and Infertility. "That is why it is imperative for couples to get tested. We can only help if we know about it in advance."
"Couples have the advantage of avoiding decisions about terminating pregnancy or destroying embryos," said Dr. Laurence McCullough, professor of medicine and medical ethics at BCM, who has published widely on ethics and obstetrics. "They will also reduce the need for subsequent invasive pre-natal testing. However, the success rate in producing a pregnancy in assisted reproduction may be lower than the natural pregnancy rate. These are all issues that the Baylor genetic counseling service routinely discusses with couples interested in pre-implantation genetic diagnosis."
In addition to CF testing, BCM geneticists offer prenatal testing for numerous syndromes that are not detectable by standard prenatal diagnostic methods, including Angelman Syndrome, Prader-Willi Syndrome and Williams Syndrome.