Three groups of researchers from Yale University, the University of California, Los Angeles and the Johns Hopkins University have replicated the results of a previous study, implicating a gene called CNTNAP2 in the development of the newly defined Type 1 autism.
Dr. Dietrich Stephan, Director of the Neurogenomics Division at the Translational Genomics Research Institute's (TGen), had found in 2006 that a mutation in this gene indicated a predisposition to autism in a specific population of Old Order Amish children from Pennsylvania.
"Our previous finding of association between loss of CNTNAP2 function and autistic behaviour has been validated in the general population. This is a very exciting step for autism research. It also highlights the enormous potential of the 'small science' approach," said Dr. Erik Puffenberger, Laboratory Director of the Clinic for Special Children, who was Dr. Stephan's collaborator in the previous study.
"Our initial work used only four affected Amish children. Careful study of these four patients uncovered the association between CNTNAP2 and autistic behaviours. From that small beginning, CNTNAP2 has now been implicated as a significant risk factor for autism," he added.
The three studies attain significance as replication is considered to be one of the most important principles in science.
"The field of genetics is replete with examples where researchers are unable to reproduce results. Here we have independent confirmation in multiple groups using large samples sizes," said Dr. Stephan.
"Now that the results of the initial CNTNAP2 gene finding have been replicated, it strongly supports the notion that the 'broken version' of CNTNAP2 is recognized as a cause of autism in the general population," he added.
Researchers at TGen are now collaborating with a nonprofit community-based organization to apply these research findings to children in Arizona who have been diagnosed with ASD.
Dr. Stephan says that the next step of his team is to develop a diagnostic to test for the CNTNAP2 mutation.
According to him, children with autism might have a better chance of developing normally, if behavioural interventions could be implemented early enough.
The research has been reported in the American Journal of Human Genetics.