Autism with intellectual disability is less heritable than autism alone, according to a new study of how the conditions run in extended families.
About a third of autistic people have intellectual disability (ID) — an intelligence quotient (IQ) of 70 or less. Autistic people with lower IQs are more likely to have spontaneous, or de novo, gene mutations than autistic people with higher IQs, studies show, suggesting that the genetic underpinnings of autism with ID differ from those of autism alone.
