ΔF 508

Question

Hello. After having an amniocentesis during my first pregnancy we discovered by chance that the fetus was a carrier of the DF508 CF mutation. We do not know which one of us is the carrier. I am pregnant now in my second child. My question is should we have testing for this mutation only, or for all the CF mutations? Thank you.

Answer

Dear friend,
During your last pregnancy you discovered that the fetus was a carrier of the ΔF508 CF mutation by checking for a large number of CF mutations. The child you gave birth to carries 50% of the genetic material of the father and 50% of that of the mother.
Today, you are pregnant again and you ask if you should be checked for all the mutations that can be checked, or only for the ΔF508. The fetus of your pregnancy carries as well 50% genetic material of the father and of the mother, but it could be the other 50% in relation to that of your first child. Consequently, this part of the genetic material might not have been checked the first time, thus you and your husband should be examined for all the CF mutations.
In case both of you turn out to be carriers for one CF mutation (we already know that one of you is carrier for deltaF508 mutation, the possibility has to be ruled out that the other partner also carries a CF mutation, either delta F508 or another one), there is the possibility then that your second child could have inherited both mutations (one from each parent) and therefore suffers from CF. If those mutations from you and your husband are known before birth, an amniocentesis can be done and it can be looked for the known mutations in the child in order to reveal if it has either none of them, is a carrier or suffers from CF.
If there is the lucky case that only one of you carries a CF mutation (namely delta F508), the second child can not suffer from CF, it can be only a carrier in the worst case.

Yours friendly,
Dr. Anna Katelari - Ioannidi

04.01.2010