TW for death.

I'm wondering if anyone can help me with the possible name of this condition. I had an uncle who lost two baby girls to a genetic condition both he and his wife were carriers for. It only affected girls, and a very early death was a guarantee for it. I don't know anything else about it, this all happened before I was even born. All of their boys were fine. Unfortunately, all of the family I can ask about this either doesn't know more, I'm not in contact with, or has passed away. With my husband and I trying to conceive, I'd like to try to get a specific name for it before we do testing, in case it's so uncommon that they wouldn't look for it.

Thanks in advance for any help you can offer.