Diagnosis

Question

Hello,
how high is the risk, in spite of negative tests after birth (those test had been done because the sister of the mother suffers from CF), that the child has still CF? The digestion seems to be o.k., a nearly permanent cough is striking. The child is 2 years old and is in contact with many other children, so that also constant infections could be underlying.

Answer

Hello,
you ask, if it is possible, that a child suffers from CF, in spite of the fact that after birth test had been done because the sister of the mother suffers from CF. You ask this question, because the child had since birth constant cough. Here it has at first to be clarified, which tests had been done and in which laboratories. If there are results of the molecular genetic investigation of the CF patient, that show the two CF mutations and a molecular genetic investiagtion had also been done to the child in question and the result could not find the known mutations, the illness of CF is extremely improbable however not totally excluded. Furthermore it has to be questioned, if the child got a sweat test with pilocarpin ionotophoresis in a certified CF center. If this was the case and the result was absolutely normal, one can assume that CF can be excluded with security.
If the above mentioned investigations could not show the mentioned results (e.g. clarity could not be achieved via the molecular genetic investigaton of the CF patient and the child), then the child should again undergo the diagnostics.

Best regards,
Dr. H.-G. Posselt

14.03.2016