My Mum killed herself when she was fortythree, and I think was undiagnosed aspie. She was a late speaker, but published author, self taught linguist (Latin, Russian, Hindi, Urdu, Bengali) and self taught pianist. In fact, she had to teach herself to read and write when she was twelve, because nobody had bothered up to that time.
My Grandma also had many aspie traits, insanely talented musician, though she'd never received any instruction, photographic memory.
Her Dad... by all accounts a very strange, driven, single minded man, so possibly, but I don't know so much about him.
My maternal grandfather, polyglot, despite no formal education, musically self taught, ambidextrous... seemed to be NT though.
My Dad has an official IQ of 168, and you'd think he'd be aspie, but he's as NT as they come. One of his uncles on the other hand was a polymath genius and chess correspondent, who must have been autie from all that is said of him.
My son is diagnosed aspie, dyspraxic. I'm diagnosed autie, dyspraxic, dyscalculic. My son's IQ is over 160, mine is over 150.
My son's father is diagnosed aspie. His IQ is in the 160s. (He was tested twice, once he got 172, but he swears it was a glitch.) He's a tone deaf polymath, whereas I'm just a musical polyglot. My son appears to have inherited the best of both of us, perfect pitch, and annoyingly brilliant at everything.
My son's paternal grandmother is also aspie, as was her Dad.
So, in other words... I think it's more like figuring out who in my family isn't on the spectrum. So far, I'd say my Dad isn't. Either that or he's brilliant enough that he just learned to fake it.