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Study Finds Risk of Autism among Younger Siblings of a Child with Autism Much Greater Than Previously Reported

Risk for Boys is Greater than for Girls, and Risk is Over 32 Percent if the Infant has More Than One Sibling with Autism

NEW YORK, N.Y. (August 15, 2011) – Autism Speaks, the world’s largest autism science and advocacy organization, joined in announcing significant findings from the largest known study of younger siblings of children who had a verified diagnosis of autism spectrum disorder (ASD). This study, based on data from the Autism Speaks High Risk Baby Siblings Research Consortium (BSRC) and led by investigators from the UC Davis MIND Institute, was published online today in the journal Pediatrics and will appear in the September issue.

The “Recurrence Risk for Autism Spectrum Disorders: A Baby Siblings Research Consortium Study” found that 19 percent of younger siblings of children with ASD developed autism, a rate significantly higher than the general population. If there were two children with ASD in the family, the risk of the third sibling developing ASD increased to more than 32 percent. The study found that the risk of an ASD diagnosis for male infants who had an older sibling with ASD was almost three times greater than the risk for female infants (26 percent compared to 9 percent). The study did not find any increase in risk associated with the gender of the older sibling, severity of the older sibling’s symptoms, or other parent characteristics such as parental age, socio-economic status or race/ethnicity.

“By pulling together data from many investigators who are studying infant siblings of children with autism, these results offer a more accurate estimate of the recurrence rate for autism in siblings,” says Autism Speaks Chief Science Officer Geraldine Dawson, Ph.D.“Surprisingly, the rate is much higher than previous estimates. This points to the important need for closely monitoring and screening siblings so that they can be offered intervention as early as possible to ensure the best possible outcome.” 

The study involved 664 infants from 12 U.S. and Canadian sites, evaluated as early as 6 months of age and followed until age 36 months. This study used gold standard diagnostic methods and comprehensive assessments by expert researchers, compared to prior studies based on more narrow diagnostic criteria. 

“It has been well established that siblings of children with ASD are at higher risk for developing the disorder, but our estimates of the recurrence rate had been based on much smaller samples,” explained Autism Speaks Director of Research for Environmental Sciences Alycia Halladay, Ph.D. who oversees the BSRC. “These findings emphasize the importance of family history as an autism risk factor that requires attention by parents and clinicians in tracking these infants from an early age to determine if the younger sibling develops ASD or a development disorder.”

“It's important to recognize that these are estimates that are averaged across all of the families. So, for some families, the risk will be greater than 18.7 percent, and for other families it would be less than 18.7 percent,” said Sally Ozonoff, Ph.D., professor of psychiatry and behavioral sciences at the MIND Institute and the study's lead author. “At the present time, unfortunately, we do not know how to estimate an individual family's actual risk.”

The High Risk Baby Siblings Research Consortium, now engaging 25 scientists at 21 institutions in the U.S., Canada, Israel and the UK, is a partnership between Autism Speaks and the National Institutes of Health, led by the National Institute of Child Health & Human Development. Autism Speaks began funding baby sibling research in 1997 and has since committed over $7 million to this project, both in scientific research and programmatic activities. Autism Speaks also provided funding to authors Ozonoff and Young for this study.

Families who have concerns about their infant’s development, who also has one or more older children with autism can contact their nearest Baby Siblings Research Consortium researcher about participating in continuing research efforts. The list of BSRC researchers can be found at http://www.autismspeaks.org/science/initiatives/high-risk-baby-sibs/consortium-researchers.

About Autism
Autism is a complex neurobiological disorder that inhibits a person's ability to communicate and develop social relationships, and is often accompanied by behavioral challenges. Autism spectrum disorders are diagnosed in one in 110 children in the United States, and one in 70 boys. The prevalence of autism has increased 600 percent in the past two decades. The Centers for Disease Control and Prevention have called autism a national public health crisis whose cause and cure remain unknown.

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 $160 million to research 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 has created resources and programs including the Autism Speaks Autism Treatment Network, Autism Speaks 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, which Autism Speaks celebrates through its Light It Up Blue initiative. Also, Autism Speaks’ award-winning “Learn the Signs” campaign with the Ad Council has received over $272 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 in 27 states thus far, with bills pending in an additional 12 states. 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.

About the Co-Founders
Autism Speaks was founded in February 2005 by Suzanne and Bob Wright, the grandparents of a child with autism. Bob Wright is Senior Advisor at Lee Equity Partners and Chairman and CEO of the Palm Beach Civic Association. He served as Vice Chairman of General Electric; and as the Chief Executive Officer of NBC and NBC Universal for more than twenty years. He also serves on the boards of the Polo Ralph Lauren Corporation, Mission Product, LLC, EMI Group Global Ltd and the New York Presbyterian Hospital. Suzanne Wright is a Trustee Emeritus of Sarah Lawrence College, her alma mater. Suzanne has received numerous awards, the Women of Distinction Award from Palm Beach Atlantic University, the CHILD Magazine Children’s Champions Award, Luella Bennack Volunteer Award, Spirit of Achievement award by the Albert Einstein College of Medicine's National Women’s Division and The Women of Vision Award from the Weizmann Institute of Science. In 2008, the Wrights were named to the Time 100 Heroes and Pioneers category, a list of the most influential people in the world, for their commitment to global autism advocacy. They have also received the first ever Double Helix Award for Corporate Leadership, the NYU Child Advocacy Award, the Castle Connolly National Health Leadership Award and the American Ireland Fund Humanitarian Award. In the past couple of years the Wrights have received honorary doctorate degrees from St. John’s University, St. Joseph’s University and UMass Medical School– they delivered respective commencement addresses at the first two of these schools. The Wrights are the first married couple to be bestowed such an honor in St. John’s history.