Well it is hard to answer this question, I suspect that some parts of the "mental health industry" would like to label our every thought, word and deed as a symptom of autism.
This is plainly wrong, but I am sure that people with an ASD tend to be more likely to have a topic which they have as a special interest than the typical NT. I will have to consider the question at length to get a better answer for you.
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Health is a state of physical, mental and social wellbeing and not merely the absence of disease or infirmity

I am not a jigsaw, I am a free man !
Diagnosed under the DSM5 rules with autism spectrum disorder, under DSM4 psychologist said would have been AS (299.80) but I suspect that I am somewhere between 299.80 and 299.00 (Autism) under DSM4.