One Gene, One Subtype

Jessica Wright writes at Scientific American:

CHD8, a gene that regulates the structure of DNA, is the closest thing so far to an ‘autism gene,’ suggests a study published today in Cell.

People with mutations in this gene all have the same cluster of symptoms, including a large head, constipation and characteristic facial features; nearly all also have have autism.

Autism is notoriously heterogeneous, perhaps involving mutations in any of hundreds of genes. Typically, researchers begin by studying people with similar symptoms and working backward to identify what causes those symptoms. But that approach has not been particularly productive.

“We’ve tried for so long to identify subtypes of autism based on behavior alone and we’ve done abysmally at that,” says lead researcher Raphael Bernier, associate professor of psychiatry at the University of Washington in Seattle.

The reverse approach — that is, beginning with people who all have mutations in the same gene and characterizing their symptoms — may prove to be more useful for simplifying autism’s complexity.