(November 5, 2010 - Insidermedicine)

A genetic deletion on chromosome 17 has been linked with an increased risk for autism spectrum disorder and schizophrenia in research published in the American Journal of Human Genetics.

Here are some recommendations regarding metabolic genetic investigations in children with global developmental delay, from the American Academy of Neurology and the Child Neurology Society:

•    Routine cytogenetic testing (yield of 3.7%) is indicated in the evaluation of the child with developmental delay, even in the absence of dysmorphic features or clinical features suggestive of a specific syndrome

•    The diagnosis of Rett syndrome should be considered in females with unexplained moderate to severe mental retardation. If clinically indicated, testing for the MECP2 gene deletion may be obtained

•    In children with unexplained moderate or severe developmental delay, additional testing using newer molecular techniques (e.g., fluorescence in situ hybridization [FISH], microsatellite markers) to assess for subtelomeric chromosomal rearrangements (6.6%) may be considered

Researchers out of Emory University in Atlanta performed cytogenetic array analysis in patients with neurodevelopmental disorders who were referred for clinical testing. Overall, they tested over 23,000 individuals with autism spectrum disorder, developmental delay, intellectual disability, or schizophrenia as well as 52,448 controls.

The investigators detected a recurrent deletion at 17q12 in 24 affected patients that was not present in any of the controls. This deleted region contains 15 genes, including HNF1B, which has been linked with renal cysts and diabetes syndrome (RCAD). A number of patients with autism spectrum disorder also suffered from kidney disease and/or diabetes. In addition, the 17q12 deletion is among the 10 most frequent pathogenic recurrent genomic deletions identified in children with unexplained neurodevelopment impairments. The researchers calculated that a carrier of this deletion would be 13.58 times more likely to develop autism spectrum disorder or schizophrenia than noncarriers.

Today’s research helps further elucidate the genetic predictors of autism spectrum disorder and schizophrenia.