Possibility of CF

Question

I am 10 weeks pregnant. After checking for 100% of CF mutations I was found to carry the DF508 mutation, while my husband carries the (c.31G>A) rs 1800072 mutation. What are the chances for CF?

Answer

Dear friend,
You are 10 weeks pregnant and you were found to carry the CF mutation DF508, while your husband carries the c.31G>A rs1800072. After getting an trophoblast sample it will be clarified which CF mutations from the above the fetus may carry.
The chances are:
25% to carry the mutation DF508
25% to carry the mutation c.31G>A rs1800072
25% to carry none of the above mutations
25% πιθανότητα to carry both DF508 and c.31G>A rs1800072 mutations.

The CF gene is a large gene, which is located in the long leg of chromosome 7. It produces a protein, the CFTR protein, which is comprised of 1480 aminoacids and which can be found on the surface of the epithelial glands of exocrine glands. Its basic function is the normal functioning of chloride channels.
Up till now there have been more than 2000 CF mutations detected, the majority of which are pathological. This means that the production, or the function of the CFTR protein is affected. In the Greek population the most common mutation is the DF508, with a rate of 53,4%. 64 mutations have been found at a rate over 0.1%, and another 64 have been detected at a rate less than 0.1%, namely in one person.
For this reason a global database, the CFTR2, has been established. It collects data from national registries and CF centers from all over the world for the clinical significance of the common CF mutations from 89052 patients. After the last data collection at 8/12/2017 the clinical importance of 374 mutation has been established.
312 mutations cause CF
36 mutations have variable clinical manifestations
13 mutations do not cause CF
13 mutations are of unknown clinical significance.

The is no reference in this database about the c.31G>A mutation, nor any kind of reference in the international scientific literature. Unfortunately, there are not data, on which to base an opinion about the probable clinical manifestations, in case the fetus carries both mutations (25% chance). If it carries none, or only one, of these mutations, it will not suffer from CF.
Yours friendly,
Dr. Stavros Doudounakis

09.09.2018