Diagnostics_2

Question

I am a carrier of the CF gene. During my pregnancy my husband underwent genetics testing in Olomouc and we were told that he wasn't a carrier. We have two boys. One of them is five years old and he has been suffering from a prolonged rhinitis since birth. The rhinitis doesn´t cease during the year. His nose is always runny and the mucus is green or yellow in colour and thick in texture. My son has constant trouble breathing, he has a nasal voice and snores at night. I frequently take him to an ENT (ear, nose and throat) specialist, but his doctor has stated that he doesn´t understand why he is filled up with mucus. My son suffers only from chronic rhinitis, otherwise he doesn´t tend to be very ill. I would like to know if he might have CF, even though my husband presumably isn´t a CF carrier. In Olomouc, the 30 most common mutations are tested.

Answer

If your child's father has been tested for the 30 most frequent mutations, there remains still a small risk, that he might be carrier of a rare mutation, that has not been detected by the test. If this should be the case and if he probably has inherited this undetected mutation to your son, this could have clinical consequences for him. From your question it does not sound as if your son shows the typical CF-symptoms, however, there are also mutations that lead not to the "classical" picture but to a milder form of the disease with an "atypical" course. Therefore, a sweat test at a specialized center measuring the chloride-concentration in the sweat by pilocarpine-ionotophoresis can help to clarify the situation; if such a test is not conclusively positive or negative, other investigations (extended genetic testing, elastase in the stool, lung function test, x-ray, nasal potential difference measuring) could help further. Consultation with and decision upon by a CF specialist operating in one of the CF centres in the Czech Republic seems reasonable.
If it can be clarified that you son is indeed only a carrier of one "CF-mutation", it has to be mentioned, that based on current knowledge, carriers are generally well and deserve their name of "healthy carriers" even if the functioning of their CFTR protein is reduced. They are not at risk of developing severe respiratory impairment. However, slight respiratory or ENT symptoms might be a little more frequent.
I suppose that he has been thoroughly tested at ENT, allergology, immunology and at a respiratory unit to rule out other possible causes of the above mentioned problems.
Dr. J. Brázova and Dr. D. d'Alquen

13.12.2011