Study: Different Genes May Cause Autism in Boys and Girls

News from Science Daily on a study from a team at the University of Washington, headed by Gerard Schellenberg:
" "It is highly unlikely that there is only one gene responsible for autism," said Schellenberg. "There may be four to six major genes and 20 to 30 others that might contribute to autism to a lesser degree.
"If an individual only gets three high-risk variants of these genes, it could mean a less-severe form of autism. And because autism is rarer in females, it may take more risk genes for a female to have autism. There also is the possibility that there might be a biological difference in autism for females versus males," he said.
"What is meaningful is that we have found evidence for two genetic subtypes of autism, male versus female and early versus late onset," added Geraldine Dawson, a professor of psychology. "This is a critical piece of information. With Alzheimer's disease research, one big breakthrough was segregating the late and early onset forms of the disease, and this led to important genetic discoveries."
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The search for autism genes is part of a long-term Autism Center effort to uncover the genetic and neurobiological causes of autism. To find regions of the human genome that contain autism genes, the researchers scanned the DNA of 169 families that had at least two siblings who met the strict criteria for autism. They also scanned the DNA of another 54 families that, in addition to having individuals with strictly defined autism, also included members who had less severe forms of the disorder, such as Asperger syndrome.
"We have been working almost 10 years to get to this point," said Schellenberg. "If we can find and confirm that a particular gene is involved in autism the field will explode. We have to find a gene so that molecular biology can be defined and we can understand what's inside autism. Until that happens, we are dancing on the outside." "

Please also note the following:
The research is part of the National Institute of Child Health and Human Development Collaborative Program of Excellence in Autism. The research is ongoing and families who have more than one child of any age with an autism spectrum disorder who are interested in participating in the UW genetics study can call toll free 1-800-994-9701.