Is there any other condition besides autism that can cause trouble under standing social rules?

Many years ago autism was defined within limits to include social interaction issues among others. In the 90's,along came the educators & funding plans for school special services and the world changed. A new umbrella term autism spectrum grouped kids that were just mentally deficient, Asperger syndrome and the autistic as one entity. This blurs the definition but all may have such problems.

ADHD combined type and ODD can both produce social interaction difficulties.