Testing of eldest child

Question

My second child has CF. Is there a chance that my eldest child has it too? It is 10 years old now and we visit the pediatrician just for vaccinations. Up to what age may CF be manifested? Should I do a sweat test to my eldest child? If it is a carrier, can I find this out easily? Is there a chance that frequent headaches are related to CF?

Answer

Dear friend,
It seems that your eldest child, 10 years old, does not have CF, since it does not present the related symptoms. In general, concerning the frequent "classical picture" of CF, symptoms (of lung involvment, malabsorption with fatty stools and failure to thrive, for example) generally occur early in childhood. However, in some cases, there are "atypical courses" of CF, with milder symptoms or only some few organs involved and in those cases the symptoms might occur late, sometimes only in adulthood.
However, a sweat test must be performed to all siblings of children with CF. If the sweat test will be negative and your child is clinically healthy, it has either inherited no CF-mutation from the parents or it has inherited only one CF-mutation and is a healthy carrier. In this case, the genetic investigation in order to find out the possible carrier state of your healthy child should be performed at an age of the child, when it is old enough to understand the issue and requests the test in person. The possible carrierstate of your child becomes relevant, if it wants to have children itself and wants to know about the risk of getting children with CF.
Frequent headaches are not related to CF.
Yours friendly,
Dr. Stavros Doudounakis and Dr. Daniela d'Alquen

31.10.2011