Discovery of Gene Variant may Explain Increased Risk of Autism in Boys

A variant of a particular gene may provide evidence for the higher risk that some children have, especially boys, for developing autism, a new study has found.

Researchers at the University of California, Los Angeles (UCLA), traced the genetic markers of the CACNA1G gene, which showed that a specific variant was present more frequently in families where two or more sons, but none of the daughters, have some form of autism.

Dr. Stanley Nelson, lead investigator and professor of human genetics at the David Geffen School of Medicine at UCLA, and fellow researchers studied a specific region of chromosome 17 that has been previously tied to autism. Variants of the genetic marker were then tied to CACNA1G, which helps calcium travel between cells.

"This alternate form of CACNA1G consistently increased the correlation to autism spectrum disorders, suggesting that inheriting the gene may heighten a child's risk of developing autism," Nelson said.

The researchers used tools from the Human Genome Project “to scan thousands of variants across all genes in the suspicious region of the chromosome and to pluck out the most common forms.”

The fact that the same genetic markers appeared over and over in the area of chromosome 17 told the researchers that they had discovered something important, Nelson said, though it is still not clear how the gene contributes to a higher risk of autism.

"This variant is a single piece of the puzzle," he added. "We need a larger sample size to identify all of the genes involved in autism and to solve the whole puzzle of this disease.”

According to the researchers, the next step in the process is to sequence the gene in people with the different variant to look at the specific changes correlated with an increased autism risk.

The study findings were published in the May 19 online version of Molecular Psychiatry.