My brother has Noonan Syndrome and as I’m currently pregnant, I’m concerned about the likelihood of me or my unborn child carrying the faulty gene. What’s the chance of my brother’s siblings carrying the Noonan gene and passing it to their children?
Noonan Syndrome is a genetic condition, but most cases arise because of a chance change in the gene in the egg or sperm going to form them. If you have none of the features of Noonan Syndrome, then it is unlikely that you have inherited it. The best way to resolve this would be for your brother to be tested, and when the genetic change is identified in him you could be tested for this—if you have not inherited it, then you would not pass it on in the pregnancy.
I don’t know what stage you are at in the pregnancy, but the local genetic service would see you as an emergency and sort his testing out for you. You could get a referral to the local genetic service, either through your GP or your midwife. It is important they know you are pregnant if they are going to see you quickly.