NEW YORK, N.Y. (December 1, 2010) - A new study published in the Journal of the American Medical Association (JAMA) and partially funded by Autism Speaks, found that children with autism have more trouble fueling the energy demands of their cells due to dysfunctional mitochondria. These new findings from UC Davis reveal several different types of mitochondrial dysfunction and suggest a novel way of screening for these deficits using blood samples.
Mitochondria, the "powerhouses" of cells, provide energy for cell functions through a cascade of enzyme complexes. Together, those enzyme complexes create energy through a process called oxidative phosphorylation. Previous studies have shown that mitochondrial dysfunction can lead to a host of disorders particularly affecting brain cells which are characterized by high energy demands. Although mitochondrial dysfunction has previously been suspected in some individuals with autism spectrum disorders, the evaluation was difficult, and typically required a sample from muscle cells.
For the study, blood samples were taken from ten children with autism and ten unrelated typically developing children, all aged 2-5 years. The researchers analyzed mitochondria in children's white blood cells. Mitochondria in the samples from children with autism were less efficient at creating energy through oxidative phosphorylation. In some, there was a genetic mutation that affected mitochondrial function. In others, the researchers observed that one or more enzyme complexes were dysfunctional. In most of the children with autism, there were many extra copies of mitochondria, which may partially compensate for each one not working optimally.
"It is remarkable that evidence of mitochondrial dysfunction and changes in mitochondrial DNA were detected in the blood of these young children with autism," said Geraldine Dawson, Ph.D., Autism Speaks chief science officer. "We look forward to seeing other groups replicate these findings. We need to understand why these differences exist. One of the challenges has been that it has been difficult to diagnose mitochondrial dysfunction because it usually requires a muscle biopsy. If we could screen for these metabolic problems with a blood test it would be a big step forward."
Cecilia Giulivi, the study's lead author, is a biochemist in the Department of Molecular Biosciences in the School of Veterinary Medicine at UC Davis and is a recipient of an Autism Speaks Pilot Award. Isaac Pessah, director of the Center for Children's Environmental Health and Disease Prevention at UC Davis MIND Institute, a recipient of an Autism Speaks Environmental Innovator Award, is a co-author. Other study authors include Yi-Fan Zhang, Alicja Omanska-Klusek, Catherine Ross-Inta, Sarah Wong, Irva Hertz-Picciotto and Flora Tassone of UC Davis.
"The real challenge now is to try and understand the role of mitochondrial dysfunction in children with autism," said Pessah. "For instance, many environmental stressors can cause mitochondrial damage. Depending on when a child was exposed, maternally or neonatally, and how severe that exposure was, it might explain the range of the symptoms of autism."
Funding for the study was provided by a UC Davis MIND Institute Pilot Research Grant, the National Institute of Environmental Health Sciences (NIEHS), the U.S. Environmental Protection Agency and Autism Speaks.
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, affecting four times as many boys as girls. The prevalence of autism increased 57 percent from 2002 to 2006. 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 $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 $235 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.
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, Chairman and CEO of the Palm Beach Civic Association and served as vice chairman, General Electric, and 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, RAND Corporation and the New York Presbyterian Hospital. Suzanne Wright has an extensive history of active involvement in community and philanthropic endeavors, mostly directed toward helping children. She serves on the boards of several non-profit organizations and is also Trustee Emeritus of Sarah Lawrence College, her alma mater. Suzanne has received numerous awards such as 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 Weizmann Institute of Science. In 2008, the Wrights were named to the Time 100 list of the most influential people in the world for their commitment to global autism advocacy.