I think this is an interesting question. I work in healthcare so I literally have to classify diseases into categories for a living. And other than Autism Spectrum Disorder, the only other use of the word disorder that I can think of that is commonly used is mental disorders. We may refer to things as mental disorders or medical disorders, but I can't think of any other condition that uses the word disorder. Maybe there are some, but I can't think of one off the top of my head to save my life.
But, and I am by no means an expert on autism, I really don't see how someone diagnosed with profound autism (think Rain Man) and very high functioning people like Elon Musk can be categorized under the same umbrella. I understand that the underlying issue is an inability to understand things like social interaction, social cues, and communication, but the difference between someone with profound versus extremely mild autism are so great, and there are so many dissimilarities, that I'm actually surprised they haven't divided them up into different conditions. I mean, I genuinely don't think that everyone diagnosed with autism has the same condition. And whenever we find out what actually causes it, I won't be surprised if the differences have different causes.
I've known people for 30 years, who were diagnosed with autism at 50, and I absolutely never would've thought that that was the case. I dated a guy for two years (30 years ago!) who now says he is autistic. And we're still friends, but I absolutely don't see the signs of being unable to read social cues or misunderstanding communications in him.
So, as the numbers of autism have increased dramatically over the years, I've always thought "no. There's something not right here. These folks have something, but they have to be different conditions and they're just being lumped together".
And my mother was a special education teacher that worked with students in a high school with autism and down syndrome, and possibly some behavioral disorders. And just hearing stories from her about how some of the smartest kids in the school ended up in her class with others that were profoundly autistic was stunning. Because part of her job was teaching job skills in the community. She took classrooms of kids to stores and restaurants where they learned to stock shelves and wash dishes, and while they were in the field, they would eat lunch at a fast food restaurant, and the kids had to be able to order and pay for their meals themselves (they gave them money to buy lunch, it was just to teach them how to count money and understand that they had to buy things that didn't cost more than the money they had). So some genius level kid in her class is out learning how to wash dishes and buy lunch when he can already do calculus. I just never understood what the hell.
But my mom, ever the comedian, would tell people when they asked her what she did for a living, "Oh, I stock shelves at Big Lots." 🙄