Is a dilated aorta found in utero a manifestation of Marfans Syndrome?

I am 36 years old and 27 weeks pregnant. My baby was diagnosed with a dilated ascending aorta at 22 weeks gestation. Only the ascending aorta is dilated, the valves, root and walls of the aorta are normal. So is the blood flow. The z score was 2.3 at 22 weeks. (5.3mm).  The widest point of the aorta had grown from 5.3mm to 6.2mm in 5 days.   My partner and I have no sign or immediate history of a connective tissue disorder or BAV. The baby does not have a bicuspid vavle either.  Has anyone evercome across anything like this? My cardiologist said this is very rare to see in utero.  I have another scan next week to see how much it has grown.  My first baby has Down Syndrome and a hole in her heart, I have been told that this is no way connected and is most likey a connective tissue disorder of some kind.  we are having a test done on the baby for Marfans Syndrome but this will take a month for the results and could be inconclusive.  Could this be anything BUT a connective tissue disorder? I am so worried and would appreciate any information or knowledge anyone has. Thank you

[grendslori]

Hello and welcome to our site. I'm sorry I cannot answer your question directly, except to say that test results can be very misleading because of the expertise of the tech running the tests. Fluid can alter a lot of things and with this baby still in utero, could that be a possibility for the rapid growth? I would certainly be asking the doctor if that could be a factor. Your baby with Downs, having a hole in the heart really does not have anything to do with this present baby's issue. All babies are born with a hole in the heart and have a Functional heart murmur as a result. Usually the hole closes within the first year; for some it closes later and still, for some, it never does. Let us know how things are going for you. Take care