After analyzing almost 10,000 individuals in the U.K., scientists have found a relationship between genetic risk factors for autism and intelligence. According to the results, genes that are associated with the development of autism spectrum disorders are also linked with better cognitive ability in members of the general population who do not have these conditions. The findings have been published in Molecular Psychiatry.
Autism Spectrum Disorder (ASD) is an umbrella term used to describe a number of neurodevelopmental disorders, including autism and Asperger’s syndrome, characterized by communication difficulties, social deficits, repetitive behaviors and obsessive interests.
There is also a significant overlap between ASD and intellectual disability with up to 75% of autistic individuals having a non-verbal IQ below 70. However, ASD can also occur in those with normal or even superior non-verbal intelligence, which is what enables us to solve problems using reasoning skills but little use of language. Despite these observations, very few studies have sought to investigate the genetic overlap between intelligence and ASD.
To address this gap in our knowledge, scientists from the University of Edinburgh, Scotland, and the Queensland Institute for Medical Research investigated close to 10,000 individuals recruited from the general Scottish population. They performed both DNA analyses on the participants and also asked them to complete a variety of tests that examine cognitive ability.
The researchers found that possessing genetic risk factors for ASD was positively correlated with general cognitive ability, logical memory and verbal intelligence. This means that non-autistic individuals who possess genes associated with autism tended to perform slightly better in cognitive tests. The researchers then extended the study by performing the same experiments on 921 individuals who had been recruited into the Brisbane Adolescent Twin Study. Once again, they observed a relationship between genes associated with ASD and intelligence.
“This study suggests genes for autism may actually confer, on average, a small intellectual advantage in those who carry them, provided they are not affected by autism,” study author Professor Nick Martin explained in a news release.
“As we begin to understand how genetic variants associated with autism impact brain function, we may begin to further understand the nature of autistic intelligence,” lead researcher Dr. Tony-Kim Clarke said in a statement.