Gene may explain why more boys have autism

LOS ANGELES, May 20 (UPI) -- A variant of a gene called CACNA1G may increase a child's risk of developing autism, particularly in boys, U.S. researchers suggest.

Researchers at the University of California in Los Angeles say classic autism strikes boys four times more often than girls. However, if including the entire spectrum of autism disorders, such as the milder Asperger syndrome, boys are diagnosed 10 times more often than girls.

Dr. Stanley Nelson of the David Geffen School of Medicine at UCLA and colleagues zeroed in on a region of Chromosome 17 that previous studies have tied to autism. The research team scoured the DNA of 1,046 members of families with at least two sons affected by autism for common gene variants, Nelson says.

The researchers used tools of the Human Genome Project to scan thousands of variants across all genes in the suspicious region of the chromosome for common forms.

The study, published in the journal Molecular Psychiatry, traced the genetic markers to CACNA1G, which helps move calcium between the cells. The study said the gene has a common variant that appears in the DNA of nearly 40 percent of the population.

"This is a strong finding," Nelson said in a statement. "We found that a common form of the gene occurs more frequently in the DNA of families that have two or more sons affected by autism, but no affected daughters."