I always wondered about Lupus. An ex-boss of mine was insanely into health. Had a yoga studio for years and only ate the healthiest food. He got Lupis at 55. The other interesting thing is that his dad lived until he was 110.
A partner of mine was diagnosed with it when she was only 24 back in the mid 1990's. Back then it was often misdiagnosed, since symptoms overlapped with other illnesses, in her case rheumatoid arthritis. The first we knew if it was when she had a stroke.