To have children - CF in the family

Question

Hello,
the good brother of my husband has a child with CF. Now my husband and I think about family planning and we are asking us the question, if we were carriers. Can we have a test done for free? According to our general practitioner, we have to pay the test ourselves (7000 Euros). Can the diagnose CF of the child be made during pregnancy?

Answer

Deart questioner,
in modern times of family planning I have to ask first for kinship:
is the good brother of your husband married to the sister of your husband? And has your nephew with CF been born from this relationship?
If yes, you can make the conclusion right that there is a CF causing mutation in the CFTR gene in the family of your husband. And yes, one can test for genetic carriership.
However I think your general practitioner is not well informed; if the diganosis of CF is for sure, a genetic testing has alreday been done, so that the human geneticist knows exactly, for which mutation he has to look for (prerequisite: 1. both of the illness causing CFTR mutations of your nephew have been found and 2. the people involved agree to share the information with you).
Furthermore, I would recommend to contact a gynecologist, to my knowledge it is routine, to contact a qualified laboratory for human genetics for getting a risk calculation in case of the wish to have children. An index case in kinship of one of the partners is as a suspected case indeed sufficient, in order to justify the costs.
To your last question: yes, in case of a known mutation in the CF-causing CFTR-gene, that causes without doubt the illness of CF, also in pregnancy the diagnosis can be made via gene testing. The method is however not free of risks (there is an ambulatory intervention necessary for getting the material for the genetic testing, for this, please talk also to your gynecologist).
Best regards,
Frauke Stanke

20.01.2017