PALO ALTO, Calif. -- An international consortium of researchers working under the auspices of Autism Speaks, the world’s largest autism science and advocacy organization, has announced new genetic discoveries from the second phase of its collaborative study: the Autism Genome Project. The results were published today in the journal Nature, one of the world’s most respected peer-reviewed scientific publications.
The Autism Genome Project (AGP) (www.autismgenome.org) consists of 120 scientists from more than 60 institutions representing 11 countries, including two members of the Stanford Autism Center at Packard Children’s Hospital: Linda Lotspeich, M.D., clinical professor of Psychiatry and Behavioral Science, and Joachim Hallmayer, M.D., associate professor of Psychiatry and Behavioral Science. Hallmayer, who chaired the consortium, noted the importance of the findings.
“In essence, we have identified specific genes that give rise to autism,” Hallmayer said. “Recognizing the genetic factors that cause this complex disorder is a critical first step to better understanding and treating its different manifestations.”
Based on analysis of high-density genotyping data collected from 1,000 individuals with autism spectrum disorder (ASD) and 1,300 without ASD, the AGP reported that individuals with autism tend to carry more submicroscopic insertions and deletions called copy number variants (CNV) in their genome than controls. Some of these CNV appeared to be inherited, while others are considered de novo, or new, because they are found only in affected offspring and not in the parents. Taken together, more of the CNVs disrupt genes, previously reported to be implicated in intellectual disability without autism or in autism, than expected by chance.
The new AGP study also identified new autism susceptibility genes including SHANK2, SYNGAP1, DLGAP2 and the X-linked DDX53-PTCHD1 locus. Some of these genes belong to synapse-related pathways, while others are involved in cellular proliferation, projection and motility, and intracellular signaling, functional targets that may lead to the development of new treatment approaches.
These findings further support an emerging consensus within the scientific community that autism is caused in part by many “rare variants” or genetic changes found in less than one percent of the population. While each of these variants may account for only a small fraction of the cases, collectively they are starting to account for a greater percentage of individuals in the autism community, as well as providing insights into possible common pathogenic mechanisms. The overlap between autism susceptibility genes and genes previously implicated in intellectual disabilities further supports the hypothesis that at least some genetic risk factors are shared by different psychiatric developmental disabilities. Finally, identification of these biological pathways points to new avenues of scientific investigation, as well as potential targets for the development of novel treatments.
“Piece by piece, we are discovering genetic mutations that can cause autism. These findings will provide answers for families about what contributed to their autism,” said Andy Shih, Ph.D., Autism Speaks vice president for scientific affairs. “Furthermore, as we have learned from examples involving other genetic risk factors of autism (e.g., Fragile X, Rett, TSC), these genetic findings help us understand the underlying biology of autism, which can lead to the development of novel treatments.”
The Autism Genome Project (AGP) is an international autism genetics research consortium co-funded by Autism Speaks, the Medical Research Council, Canadian Institutes of Health Research, Health Research Board (Ireland), Genome Canada, and the Hilibrand Foundation. Additional support for Phase 2 of the AGP was provided by the National Institutes of Health.
About Stanford Children’s Health and Lucile Packard Children’s Hospital Stanford
Stanford Children’s Health, with Lucile Packard Children’s Hospital Stanford at its core, is an internationally recognized leader in world-class, nurturing care and extraordinary outcomes in every pediatric and obstetric specialty from the routine to rare, for every child and pregnant woman. Together with our Stanford Medicine physicians, nurses, and staff, we deliver this innovative care and research through partnerships, collaborations, outreach, specialty clinics and primary care practices at more than 100 locations in the U.S. western region. As a non-profit, we are committed to supporting our community – from caring for uninsured or underinsured kids, homeless teens and pregnant moms, to helping re-establish school nurse positions in local schools. Learn more about our full range of preeminent programs and network of care at stanfordchildrens.org, and on our Healthier, Happy Lives blog. Join us on Facebook, Twitter, LinkedIn, and YouTube.
Lucile Packard Children’s Hospital Stanford is the heart of Stanford Children’s Health, and is one of the nation’s top hospitals for the care of children and expectant mothers. For a decade, we have received the highest specialty rankings of any Northern California children’s hospital, according to U.S. News & World Report’s 2014-15 Best Children’s Hospitals survey, and are the only hospital in Northern California to receive the national 2013 Leapfrog Group Top Children’s Hospital award for quality and patient care safety. Discover more at stanfordchildrens.org.
About Autism Speaks
Autism Speaks is North America’s largest autism science and advocacy organization. Since its inception in 2005, Autism Speaks has made enormous strides, committing over $142.5 million to research through 2014 and developing innovative new resources for families. The organization is dedicated to funding research into the causes, prevention, treatments and a cure for autism; increasing awareness of autism spectrum disorders; and advocating for the needs of individuals with autism and their families. In addition to funding research, Autism Speaks also supports the Autism Treatment Network, Autism Genetic Resource Exchange and several other scientific and clinical programs. Notable awareness initiatives include the establishment of the annual United Nations-sanctioned World Autism Awareness Day on April 2 and an award-winning “Learn the Signs” campaign with the Ad Council which has received over $210 million in donated media. Autism Speaks’ family resources include the Autism Video Glossary, a 100 Day Kit for newly diagnosed families, a School Community Tool Kit and a community grant program. Autism Speaks has played a critical role in securing federal legislation to advance the government’s response to autism, and has successfully advocated for insurance reform to cover behavioral treatments. Each year Walk Now for Autism Speaks events are held in more than 80 cities across North America. To learn more about Autism Speaks, please visit www.autismspeaks.org.