ZOMG UPDATE!!!
I just talked to my Mom today for quite a long time on the phone. Another moment of "Why didn't you tell me this before Mom?!".
Anyways, my mother has Lupus. I'm not kidding you. Her doctor said it's only affecting her 1 foot. But she did indeed test positive for Lupus, several years ago.
Ah HA. So a definite AI link in my mother's side of the family.