Rare mutations of CF in pregnancy

Question

I am 18 weeks pregnant and carry the mutation.Arg31Cys (c.91>T), while my husband is carrier of the mutation p.Tyr301Cys. I am going to have an amniocentesis. Could you give me some information about these mutations? If the embryo inherits both of them is there any data about if and how will CF present?

Answer

Dear friend,
Both you and your husband are carriers of rare CF mutations. When these mutations on their own are combined with a typical CF mutation the result is the presentation of a mild or atypical form of CF, however data is not enough at this time point to predict the course of the disease. Besides, mutation analysis only gives a rough direction but it has to be clearly stated that the individual clinical course and especially the degree of lung involvement cannot be predicted according to the genotype, as many other genetic (modifier genes, etc.) and environmental factors play a role and the severity of disease differs substantially even between patients with the exact same mutations.
If the embryo carries both these mild mutations, probably it will present an atypical form of CF, where the most probable symptom may be, if is a boy, obstructive azoospermia (absence of sperm in the semen – sterility).
I cannot predict if, at what age and with what symptoms the disease will present itself.
Yours friendly,
Dr. Stavros Doudounakis

25.03.2013