People with AS diagnoses develop language normally, but often have difficulty with social interactions, fine and gross motor coordination, and eye contact. They may be extremely passionate about just one or two topics, with little patience for small talk. They also may struggle to handle normal daily activities, such as organizing time, managing conflict, or even facing the sensory overload presented by malls and grocery stores.
Adults with AS may appear painfully shy, or they may be extremely outgoing - sometimes to the point of being "in your face." That's because people with AS often misinterpret social interaction. Questions they may ask themselves might include: How far away do I stand from another person? How long can I talk about my favorite subject? What's the right answer to "how are you?"
... and body language is a mystery.
In his autobiography, The Art of the Deal, Trump talked about what a good thing it is to be able to fixate on certain issues until you figure out a way of getting them done successfully. In another of his books (Think Big maybe or perhaps Think Like a Champion?), he talked about barely being able to sleep because he is so excited to get back to his business dealings. Obsessing over specific topics sounds a lot like Aspie special interests. All his pacing, awkward gestures, and repeative movements (on full display during the second debate) could also be Aspie stimming.
In Surviving at the Top, he wrote about how passionately he loathes small talk and how he saw Ivana dragging him off to non-business related social functions as one of the key reasons their marriage failed. His Aspie-level frankness has gotten him into trouble many times too. I think it would be extreme to consider him actually autistic, but since autism is now considered a spectrum of various traits, it might not be too far-fetched to claim he might have some high-functioning austistic/Aspie traits (there have also been certain rumors for a while in this regard about his youngest son, Barronand remember autism is very heritable). Fortunately, these sort of neurological differences often correlate with a high IQ and great success (think Einstein and Bill Gates).