Risk of Noonans

My husband’s uncle who is 49 has Noonans syndrome. We are about to start trying for a baby and I don’t know how likely it is that my husband will carry the gene. I am also wondering if anyone knows if he can be tested for this. Is there a predominance of the gene being passed from fathers or mothers? Hope someone can help me as I’ve trawled the net and can’t seem to find this info. Thanks!!

If your husband has Noonan Syndrome, then a child of his has a 50% chance of having N.S.

If he doesn’t have Noonan Syndrome, then the chance is the same as any other person who does not have N.S. - sporadic mutations are not common.

It is possible that your husband has N.S. but does not know it (sometimes physical characteristics are subtle and medical issues are not severe). If your husband’s uncle has tested positive for one of the four mutations known to cause N.S. , then a geneticist could have your husband’s blood tested for this mutation. If your husband’s uncle has a clinical diagnosis, then a geneticist would need to use medical history, family history, photographs, . . . to determine if your husband may also have it.