Genes linked with a greater risk of developing autism may also be associated with higher intelligence, a new study has found.
The study found new evidence linking genetic factors associated with autism to better cognitive ability in people who do not have the condition.
Although up to 70 per cent of individuals with autism have an intellectual disability, some people with the disorder have relatively well-preserved, or even higher than average, non-verbal intelligence, the researchers said.
Autism is a developmental disability that can cause significant language and speech difficulties. Non-verbal intelligence enables people to solve complex problems using visual and hands-on reasoning skills requiring little or no use of language.
Researchers at the Universities of Edinburgh and Queensland analysed almost 10,000 people recruited from the general population of Scotland. Individuals were tested for general cognitive ability and had their DNA analysed.
The team found that among people who never develop autism, carrying genetic traits associated with the disorder is, on average, linked to scoring slightly better on cognitive tests.
Researchers found further evidence of a link between autism-associated genes and intelligence when they carried out the same tests on 921 adolescents who were part of the Brisbane Adolescent Twin Study.
"Our findings show that genetic variation which increases risk for autism is associated with better cognitive ability in non-autistic individuals," said Dr Toni-Kim Clarke, of the University of Edinburgh's Division of Psychiatry, who led the study.
The study is published in the journal Molecular Psychiatry.
