Siblings of children with CF

Question

My firstborn child is 16 and visits the doctor just for vaccinations, as does my second born who is 10 years old. Their little brother is 3 years old and has CF. Do they need to be tested? The truth is that just the idea of testing makes me very anxious. The oldest one is in her last year at school, and I do not know if I must burden her with the testing. What should I do?

Answer

Dear friend,
I do not know the symptoms which motivated your doctor to ask for a sweat test for your three year old child in order to verify that the child has CF.
What you should know is that the rule for the siblings of a child, who has a positive diagnosis for CF, is that they must be checked for CF, irrespective of them presenting the symptoms of the disease or not.
The siblings of a child, who has a diagnosis of CF, have considerable chances to suffer from CF, since it is a hereditary disease, that means that there is a 25% chance for the presentation of the disease for each birth.
In your case the sweat test is performed not to confirm that your other children suffer from CF, but to confirm that they do not suffer from it.
Personally I think that your older children do not suffer from CF, because they do not present any of the symptoms of the disease, but still they must have the sweat test, in order to officially confirm that they do not suffer from the disease.
Yours friendly,
Dr. Stavros Doudounakis

12.06.2013