We have one son who was PTN11 Noonan Syndrome and another son who has a clinical diagnosis. Last year, the son with the clinical diagnosis was retested for Noonan Syndrome and was found to have a chromosome sex duplication. Should we have our other son retested? Is it possible for a Noonan’s child to carry another duplication?

This is a possibility as just because you have a particular gene test result for Noonan Syndrome doesn’t mean there wouldn’t be other things. That can sound worrying but actually differences in genetic material are really common and if we look closely enough we’ve all got them. Larger differences that can have an effect are a bit less common but it would be wise to get it checked out.