Mutation carrier and pregnancy

Question

I am 18 weeks pregnant (normal conception) and read about CF in the Internet. My gynecologist did not prescribe the relative test because he thought it was unnecessary. I did it, nonetheless, and the results were positive for 7t/7t and negative for the other 49 mutations. My gynecologist recommended that my husband should be tested as well, but he thought that the danger for the baby to have CF was improbable because my husband had to have the exact same mutation as I. We are expecting the results, but by reading the Ecorn site I realized that if both parents are carriers of a CF mutation then the baby may have CF, even if the mutations are not the same. If my husband is a carrier, do I have to do an amniocentesis?

Answer

Dear friend,
The mutation 7t has clinical importance when it coexists with the mutation R117H on the same chromosome and if the baby is a boy. In this case the person may present obstructive azoospermia (absence of sperm in the semen – sterility) with or without respiratory symptoms (Castellani, JCF 2008; Kiesewetter, Nat Genet 1993). If it is a girl she may present a mild form of the disease or none at all. (Always assumed that mutation R117H-7t is combined with another CF-causing mutation or is present on both chromosomes).
Whatever your husband may be (carrier of a CF mutation or not), the embryo will not have CF, unless you carry the mutation R117H, a possibility that I presume has been eliminated by the test for the other 49 mutations you have undergone.
Yours friendly,
Dr. Stavros Doudounakis

25.03.2013