Autism is nearly five times more common in boys than girls. Now, new research suggests that gender differences could be key to understanding how to treat the disorder.

An international team of scientists analyzing the genetic makeup of more than 1,600 people with autism has identified a gene known as SHANK1 that when mutated, may be responsible for triggering some cases of autism.

Most significantly, however, they found a single family where six individuals carried the gene alteration. The four male family members with the variance all had autism, while two women were unaffected by the developmental disorder despite having the mutation.

The findings reported online Thursday in The American Journal of Human Genetics may help explain why autism is more common in males than females and lead to treatment options, the researchers said.

“This study indicates that there may be a protective factor preventing these female carriers from developing ASD,” said Stephen Scherer of The Hospital for Sick Children in Toronto who was one of the study authors. “(This) protective factor may one day be used to prevent or treat the disorder.”