Why is autism more common in boys?
“Got Questions?” is a new weekly feature on our blog to address the desire for scientific understanding in our community. We received over 3000 responses when we asked what science questions were on your mind. We answered a few here and the Autism Speaks Science staff will address the other themes we received in this weekly post.
In 2009, researchers discovered an autism risk gene on chromosome 17 called CACNA1G that is more common in boys than girls. The gene is partially responsible for regulating the flow of calcium in brain cells. Calcium is very important in transmitting information and having too much of the mineral may cause the overexcitability of neural circuits that we have seen in autism. This is a promising finding, though there have been other suggestions. Some researchers have suggested that females are less vulnerable to developmental disorders because of their neurochemistry. Also, autism risk genes have been found on the X chromosome. Since girls carry two X chromosomes, they have two copies of these genes, and one of the genes may not carry the mutation. This may help to protect them against the effects of an X-linked mutation. Although we don’t have a firm answer yet, the gender imbalance in autism diagnoses is a clue that researchers are pursuing actively.