Researchers Demonstrate First Common Genetic Risk Factors For Autism

Main Category: Autism
Also Included In: Genetics
Article Date: 29 Apr 2009 - 3:00 PDT

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Researchers have made an important step forward in understanding the complex genetic structure of autism spectrum disorders. A researcher collaboration, including geneticists from the University of Pennsylvania School of Medicine and The Children's Hospital of Philadelphia (CHOP), have detected variations along a genetic pathway that is responsible for neurological development, learning and memory, which appears to play a significant role in the genetic risk of autism. Their findings will be published online in the journal Nature on April 28.

Evidence suggests there is a strong genetic component increasing the likelihood of an autism diagnosis, estimated to impact 1 in 150 children in the United States. The study findings suggest that a particular genetic variation, found on a cluster between CDH10 and CDH9, is commonly found in children with autism, according to co-senior author Gerard Schellenberg, PhD, professor of pathology and laboratory medicine at the University of Pennsylvania School of Medicine.

"We studied more than 10, 000 children of whom more than 4, 500 had been diagnosed with an autism spectrum disorder and found a common genetic variation that increases the risk of a child developing autism, along with a rarer genetic change that contributes to some cases of autism," Schellenberg said. "This work yields important clues on what goes awry during development in children with autism and will help us focus on what is the cause of autism at a molecular level."

"It is very compelling to find evidence that mutations in genes involved in brain interconnections increase a child's risk of autism, because other autism researchers have made intriguing suggestions that autism arises from abnormal connections among brain cells during early development," said study leader Hakon Hakonarson, MD, PhD, director of the Center for Applied Genomics at The Children's Hospital of Philadelphia and associate professor of Pediatrics at the University of Pennsylvania School of Medicine.

In a second study, researchers found deleted or duplicated genes along two major central nervous system gene networks in children with autism spectrum disorders. The changes were on the ubiquitin pathway, which is responsible for regulating synaptic operations and nervous system development. One ubiquitin-related gene studied, UBE3A, was previously thought to be connected to autism, while another, PARK2, was previously found to mutate and lead to juvenile Parkinson's disease. Future research will test the effects of the missing or extra genetic copies.

The first study was supported in part by grants from the Department of Veterans Affairs, National Institutes of Health, and the Autism Genome Project Consortium funded by Autism Speaks. The Children's Hospital of Philadelphia, Autism Speaks and the National Institute of Child Health and Human Development funded the second study.

PENN Medicine is a $3.6 billion enterprise dedicated to the related missions of medical education, biomedical research, and excellence in patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System.

Penn's School of Medicine is currently ranked #3 in the nation in U.S.News & World Report's survey of top research-oriented medical schools; and, according to the National Institutes of Health, received over $366 million in NIH grants (excluding contracts) in the 2008 fiscal year. Supporting 1,700 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.

The University of Pennsylvania Health System (UPHS) includes its flagship hospital, the Hospital of the University of Pennsylvania, rated one of the nation's top ten "Honor Roll" hospitals by U.S.News & World Report; Pennsylvania Hospital, the nation's first hospital; and Penn Presbyterian Medical Center. In addition UPHS includes a primary-care provider network; a faculty practice plan; home care, hospice, and nursing home; three multispecialty satellite facilities; as well as the Penn Medicine at Rittenhouse campus, which offers comprehensive inpatient rehabilitation facilities and outpatient services in multiple specialties.

Source: University of Pennsylvania School of Medicine