An international team of scientists led by Emory University has identified the deletion of a genomic region on chromosome 17 as a significant risk factor for autism spectrum disorders (ASD) and schizophrenia.
A mutation of one of the genes in the deleted interval already is a known cause of renal cysts and diabetes syndrome (RCAD).
Scientists have known that autism and schizophrenia are strongly influenced by genetic mutations. Although they have shown that rare copy number variations -- insertions or deletions of genomic material -- play a common and overlapping role in the two disorders, they had not previously identified this specific copy number variation (CNV), which confers very high risk.
The research team performed cytogenetic array analysis in patients with neurodevelopmental disorders referred for clinical testing.
They detected a recurrent deletion at 17q12 in 24 patients out of more than 23,000 patients with ASD, developmental delay, intellectual disability, or schizophrenia. This deletion was not present in any of 52,448 control individuals.
The deleted 17q12 region contains 15 genes, including HNF1B, the gene associated with RCAD. A number of the ASD patients in the study were found to have kidney disease and/or diabetes as well. RCAD patients, as opposed to what was initially believed, also often have neurodevelopment disorders.
Autism, which is characterized by impairments in social interaction, communication deficits, and repetitive patterns of behaviour, is the most severe manifestation of the neurodevelopment disorders known as autism spectrum disorders (ASD). The research will be published in the American Journal of Human Genetics.