"The biggest challenge to finding the genes that contribute to autism is having a large and well studied group of patients and their family members, both for primary discovery of genes and to test and verify the discovery candidates," said Aravinda Chakravarti, professor of medicine, pediatrics and molecular biology and genetics at the McKusick-Nathans Institute of Genetic Medicine at Johns Hopkins, and one of the study's senior authors. "This latest finding would not have been possible without these many research groups and consortia pooling together their patient resources. Of course, they would not have been possible without the genomic scanning technologies either."

Still doesn't seem like it's touching on why there is the sudden spike in autism...