There's an interesting NPR interview Questlove did recently, he and Terry Gross discuss things like his characteristic "nonchalance," obsessive memory and developmental concerns his parents had. When asked if he could have been diagnosed with something as a child, he replies "I think there are different degrees of autism," and while he didn't fit any known criterion then, his parents were concerned enough about things like his obsession with spinning objects (could watch a record player for hours) to take him to "find out if something was wrong."
He talks about finding things easy that others find hard, like writing long compositions with multiple parts and time changes, but not having the "pop sensibility" to write anything simple. Also responds that if quizzed about it, he'd "without a doubt" know the BPM of most of the 70,000 songs on a harddrive he DJs with. There are some other developmental things, like early technical interests, and obsessions with minutiae such as the instances a green & yellow color scheme was used on Soul Train (Would link to it but for WP's algorithmic spammer defenses). He seems a true craftsman, and I can say from experience he's a humble yet riveting stage presence.