According to a study published in the journal Nature Neuroscience, people with autism spectrum disorder can be classified into four distinct subtypes based on their brain activity and behaviour. In the study, the researchers from Cornell University analysed the data from 299 people with autism and 907 people who were not autistic.

They observed patterns of brain connections linked to behavioural characteristics in autistic individuals, including language ability, social effect, and repetitive or stereotypical behaviours. They established that the four subgroups of autism could be duplicated in a different dataset and proved that variations in regional gene expression exist. They also added that protein-protein interactions are responsible for the variations in the brain and behaviour.

Senior author Dr. Conor Liston, an associate professor of psychiatry and neuroscience in the Feil Family Brain and Mind Research Institute at Weill Cornell Medicine, explained that, like many neuropsychiatric diagnoses, individuals with autism spectrum disorder experience many different types of difficulties with social interaction, communication, and repetitive behaviours.

He added that the findings of the study can help in finding new approaches to discovering subtypes of autism, which can one day lead to new approaches for diagnosis and treatment. The findings of the study showed that there are four clinically distinct types of autistic people. Two of the groups showed verbal aptitudes that were above average. One group also had severe deficits in social communication but less repetitive behaviours, while the other had more repetitive behaviours and less social impairment.

The subgroup with more social impairment had more hyperactive connections between the areas of the brain that process visual information and aid in identifying the most important incoming information. In the group with more recurrent activities, these same connections exhibited weaker behaviour.

The team also analyzed gene expression that explained the atypical brain connections present in each subgroup to better understand what was causing the differences and found many were genes previously linked with autism. Additionally, they found that oxytocin, a protein previously linked with positive social interactions, was a hub protein in the subgroup of individuals with more social impairment but relatively limited repetitive behaviours. 

(Source: https://theprint.in/health/study-discovers-four-different-autism-subtypes-based-on-peoples-brain-behaviour/1508621/ )