CF test?

Question

As part of an infertility treatment it was found out by a gene test that my husband has a genetic disposition for cystic fibrosis. After ICSI (Intracytoplasmic sperm injection) we have a daughter. Besides a chronic recurring sinusitis with very viscous mucus she has no signs of a disease. I do not have a disposition for CF, therefore she can only have one disposition for it. Or should we have her tested anyway?

Answer

Hello,

You report that your husband has had an infertility treatment and that as part of it mutations (or only one mutation?) for CF were found. In your case a molecular genetic test was done as well but no mutations for CF were found. After an ICSI you have a daughter. She suffers from chronic sinusitis with very viscous mucus and you are asking yourself if it would be safer to have a diagnosis of exclusion done.
It would be necessary to have further information before an answer can be given. Was your husband diagnosed with two typical CF mutations or does he have the syndrom of obliterated Vas deferens? Furthermore, it would be important to know if in your case a complete sequencing of the CF gene was done or if only the about 39 most common mutations for CF were tested and excluded. Most probably your husband has a special form of CF with pancreatic sufficiency. Therefore, it would be theoretically possible that your daughter has CF – especially if in your case not a complete sequencing of the CF gene was done. Since a chronic sinusitis can be a first manifestation predictor of an atypical CF and since your are worried it does make sense to clarify this question.
In your family situation it would make the most sense to arrange at first a molecular genetic test and to look for the mutation or the two mutations which were diagnosed in your husband. Is none of these mutations found in your daughter, CF can be excluded with great reliability. If one of the mutations is found in your daughter, a complete sequencing of the CF gene should be done with the blood sample of your daughter if such a test was not done in your case.
Since the problem is very complex given your family situation it would be important to discuss this question with physicians from a CF center [a website with addresses was given in the original German question] so that the next steps with the human genetics can be planned.
At all events you should start the clarification quickly because you will otherwise be worried the whole time. We wish you and your family good luck.

All the best,
Dr. H.-G. Posselt

11.09.2013