MRI connects genetic autism, structural abnormalities in brain

The duplication or deletion of a small piece of chromosome is one of the most common causes of genetic autism spectrum disorder. Researchers used MRI to examine 331 individuals to identify structural abnormalities in such brains.

The research—led by Julia Owen, PhD, a brain researcher at the University of Washington in Seattle, working at the University of California, San Francisco—was published online Aug. 8 in Radiology.

"People with deletions tend to have brain overgrowth, developmental delays and a higher risk of obesity," said Owen et al. wrote. "Those with duplications are born with smaller brains and tend to have lower body weight and developmental delays."

The study featured 79 deletions carriers, 79 duplication carriers, 64 unaffected family members and a control group of 109 participants. MRIs showed significant differences in those with and without genetic disorders.

MRI showed a thicker corpus callosum, associated with deletion, was associated with difficulty in daily living and communication. Duplication carriers with decreased white matter and corpus callosum volume was connected with decreased verbal IQ scores, compared to duplication carriers without such structural abnormalities.

"Often studies like this focus on high-functioning individuals, but this was an 'all-comers' group," wrote Elliott Sherr, MD, PhD, head of the Brain Development Research Program at UCSF. "We didn't do mathematical algorithms but rather used the trained eyes of neuroradiologists to evaluate the scans of a full range of individuals. When you look at a broad range of people like this, from developmentally normal to more significantly challenged, you're better able to find these correlations."