Mutation DF508 / R117H 7T

Question

Hello,
I am 20 weeks pregnant and we just learned that our baby has inherited by our mutations.
My husband is a carrier of the DF508 mutation and myself the R117H 7T.
Can you tell us about the symptoms that our child could have, how does this will lead in his daylife?
Thank you in advance for your answer.

Answer

Hello,
If I have well understood your question, you have just learned that the prenatal examination performed on a sample of placenta on the side of the embryo showed that it was carrying the two mutations, one inherited from you ( R117H 7T) and the other from the father (F508del).
The F508del mutation is causing cystic fibrosis when associated with another mutation also known as CF causing.
The R117H mutation is unique insofar whether it causes or not CF depends on the structure of another region of the gene called poly-T variant. This variant may have the form 5T, 7T or 9T. On the gene you transmitted the R117H mutation is associated with 7T variant. Information extracted from the CFTR2 database indicate that it is unlikely that the F508del and R117H 7T association results in CF: however, it may sometimes be the cause of infertility in man and in both genders, symptoms similar to those observed in CF but mild.
I add that the R117H-7T association was recently withdrawn in France from the kit of 30 mutations used for CF newborn screening because most individuals who were carriers in combination with a CF causing mutation (F508del or other) had no particular symptoms after several years of follow-up.
If you want further details, I suggest you to contact the molecular biology laboratory that performed the prenatal examination and seek for medical genetics consultation.
Hope this response is helpful.
Best Regards.
Gilles RAULT,MD, CF Center Roscoff

08.03.2015