Only mother is carrier, is CF now excluded?

Question

At the 20-weeks ultrasound echodense intestines were seen. Research has been done whether my partner or myself have the CF mutation. Yesterday, after 2 weeks of uncertainty, we had the reassuring call.

I indeed seem to be a carrier and my partner not. As I understand CF is now excluded, but they said by the phone that it happens rarely but that they still could find something in my partner. Now they are going to perform tests on his blood.

Can it really happen that they first say that my partner does not have the mutation and then it turns out that he actually is a carrier?

Tomorrow we have to go to the hospital for another ultrasound and then, of course, I will ask it. But it is still haunting in my head. Hopefully, I can already get some clarity about it.

Answer

Thank you for your question.

CF is caused by mutations in the CFTR gene. Each individual has 2 CFTR genes, one gene is inherited from the father, the other gene is inherited from the mother. Individuals who carry a mutation on only 1 CFTR gene are called CF carriers.

Your partner has been tested and the result does not show a CF mutation. However, routinely they only screen for the 35 most frequent mutations. It is indeed very costly and close to impossible to check all of the already 1900 different known CF mutations. It means that –with no abnormality found on the routine test - the chance that your partner is a carrier is small, but not impossible.

With kind regards
Prof. K. de Boeck

19.07.2015