Children with autism and their siblings share similar patterns of reduced activity in brain regions linked to empathy, according to new research carried out at the University of Cambridge, UK. The researchers believe these findings could lead to a greater understanding of the role of genes in autism and the development of techniques for predicting the risk of developing autism in the future.
The study, which was carried out by a team of researchers led by Dr Michael Spencer with the backing of the Medical Research Council's Cognition and Brain Sciences Unit, used functional Magnetic Resonance Imaging (fMRI) to detect active areas of the brain in response to images of different human expressions.
The researchers initially compared the brains of autistic children to children with no family history of autism and found those with autism displayed reduced brain activity in regions involved in responding to other people's emotions. This is not a new finding – a known feature of autism is a difficulty in detecting emotional signals such as body language and facial expressions. However, when the researchers went on to look at the unaffected siblings of the children with autism, they found a very similar pattern of reduced activity in the same brain regions.
Dr Spencer said: 'We were struck by how similar the activity was in unaffected brothers and sisters compared to their sibling with autism. [This] seems to suggest that this is a shared pattern of activity due to inherited genes that may make family members at increased risk of autism'.
Previous research has demonstrated there is a genetic basis for autism – children with an older sibling with autism are twenty times more likely to be autistic than the general population. What remains unclear, however, is why this is the case, and which genes are associated with the increased risk of developing autism. This new study, published in the journal Translational Psychiatry, is the first to link the ability to recognise facial emotion in siblings with and without autism.
Dr Spencer added: 'The brain's response to facial emotion could be a fundamental building block in causing autism and its associated difficulties. It is likely that in the sibling who develops autism, additional, as yet unknown steps – such as further genetic, brain structure or function differences – take place to cause autism'.
While the authors of the study are hopeful that the research could lead to improved screening or even treatment for autism in the future, they believe that these findings are likely to just be the beginning of understanding the many factors that drive the development of autism.