Autism Gene Found in Chromosome 11

A Canadian-led international research team has pinpointed a new region of DNA thought to cause some cases of autism in children.

The consortium of scientists – 137 from 50 centres worldwide that make up the Autism Genome Project – analyzed DNA from about 1,600 families with autistic children to try to zero in on a specific group of brain cells and the genes that affect their development and function.

Their analysis led them in part to a region on chromosome 11, as well as to a gene known as neurexin 1, part of a family of genes believed to be important in communication between neurons, particularly during the brain's development. Autism has always been more so of a mystery, with more cases popping up everywhere affecting 1 in 165 children. Children with autism have difficulty interacting and communicating with others and exhibit repetitive behaviours. The cause, however, has never been fully understood. Scientists found that a person's DNA does not contain just two sets of genes, one from each parent, but also on occasion multiple copies of one or more genes and some that are missing altogether called "copy number variations," or CNVs. "Not only have we found which haystack the needle is in, we now know where in the haystack that needle is located," (The human genome is made up of about 30,000 genes, each containing 100,000 "letters," or chemical base-pairs called nucleotides.)

"This is a major breakthrough in our efforts to better understand the disorder and improve diagnosis and treatment for patients and their families," he said. Isolating those areas could one day allow for a test that would confirm the autism diagnosis in children exhibiting symptoms and tell family members whether they, too, carry the combination of genetic defects that could be passed on to their children.