I'm looking for a genetic disease/disorder. I've done some googling and some reading on wiki & some medical sites but there's SO much around and I really don't know where to begin. What I need is for a woman to be suffering & eventually die - young, in her late 20s-early to mid 30s, and to pass some form of affliction to her young daughter who will die during (young) childhood. Her (older) son is unaffected (medically).
Obviously whatever this condition is, she needs to be able to concieve, carry and give birth to two children, one of whom (a son) is healthy, and the other, a daughter, is not. If possible, there needs to be quite substantial deterioration of the conditions of both mother & daughter, enough to have a lasting emotional effect on the boy, who essentially watches his mother and sister suffer and die. (If this isn't possible, the girl dying at/shortly after birth would also work.)
If anyone can suggest something I can read more about, I would be so, so grateful. I've searched genetic disease, genetic disorder, female genetic disease/disorder & looked at various pages about conditions including Tay-Sachs and Huntington's disease (which in many ways would work).
My story is set in this universe, present-day, so making something up wouldn't really work (especially as it's a fanfic for a medical show!).
Thank you SO SO much to anyone who can help!