US researchers have identified a variant in a gene dubbed CACNA1G that confers susceptibility to autism, especially in boys.
"This is a strong finding," Dr. Stanley F. Nelson, from the University of California, Los Angeles, said in a statement. "No one has scrutinized the role that CACNA1G plays in autism."
He added, "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. Our study may explain why boys are more susceptible to the disorder than girls."
According to the report in the journal Molecular Psychiatry, previous research has identified a region on chromosome 17 as a likely susceptibility region for autism. With this knowledge, Nelson's team looked for recurring genetic markers on the chromosome in 1046 members of families with at least two autism-affected sons.
Many markers were found around CACNA1G, which encodes a protein involved in transporting calcium between cells. A common variant of the gene was present in 40 percent of family members.
The findings suggest that inheriting the gene variant "may heighten a child's risk of developing autism," Nelson said.
The next step for the researchers is to sequence CACNA1G to determine the exact genetic change responsible for the elevated autism risk.
SOURCE: Molecular Psychiatry, online May 19th, 2009. - (Reuters Health, June 2009)