New study results from the largest ever twin study that confirm the role genetics plays in autism spectrum disorders (ASDs) have been announced by the Kennedy Krieger Institute. The study also suggest that environmental factors play a role.
Published in the October issue of Archives of Pediatrics and Adolescent Medicine
, the study examined concordance rates between identical and fraternal twins, or the likelihood that if one twin has a certain genetic characteristic, the other twin will possess the same characteristic. Utilizing data obtained from the Interactive Autism Network (IAN) Project, the largest pool of autism data in the world, the study builds upon nationwide research contributions made by the IAN Project.
By registering with the IAN Project, individuals affected by ASDs and their families provide valuable data to researchers in a secure online setting from the comfort of their home or office. Furthermore, the IAN Project connects individuals with ASDs to researchers by matching them with local and national research studies for which they qualify in order to speed recruitment. The online autism registry was specially designed to lead researchers to study twin sets, as twin studies can determine possible genetic and environmental contributions to autism, which is widely thought to be the neuro-psychiatric disorder most influenced by genetics.
''Within just two years of launch the IAN Project has collected the largest group of autism twin sets in the world, which is a tremendous step forward for autism research,'' said Dr. Paul Law, Director of the Interactive Autism Network Project at the Kennedy Krieger Institute in Baltimore, Maryland and lead author of the study. ''Twin studies are a leading contributor to our understanding of autism, and the findings from this particular study show us that both genetic and environmental factors play a role in the disorder.''
About the study
Conducted over the course of two years, the study confirmed previous findings that identical twins are more concordant than fraternal twins for an ASD. However, the concordance rate for fraternal twins was higher than in previous twin studies and much higher than in previous sibling studies, suggesting that environment may be playing a more important role. The data also showed that identical twin girls had a higher concordance rate than identical twin boys (100 percent vs. 86 percent, respectively). This new finding adds to growing evidence that gender plays an important role in the genetics of ASD.
In addition, the study results suggest that concordant fraternal twins are more likely to have different diagnoses on the autism spectrum when compared to concordant identical twins. Likewise, there is a longer gap between the diagnosis of fraternal twins than identical twins. The average gap in timing of diagnosis for fraternal twins is 5 months while the average gap for identical twins is only 2 months. These findings show that even when fraternal twins both have an ASD, the severity, type and course of autism is more likely to be different.
''These novel findings are made possible only by the large number of twins participating in the IAN Project. Further research is needed to confirm our results,'' said Dr. Law. ''The goal is for more and more researchers to start utilizing the IAN Project to aid in their autism research so we can speed our search for answers.''
Changing the Face of Autism Research
Each year, many autism studies face significant delays or are not able to be completed because researchers can not find enough qualified participants. In 2007, the Kennedy Krieger Institute addressed this need by launching the IAN Project, the first national autism registry that has met significant milestones in just two years with over 30,000 individuals registered and representation of all 50 states. Through IAN Research researchers are able to submit applications to utilize the registry data in their research as well as work with IAN Project staff to notify qualified individuals with ASDs and their families of studies. To date, over 200 studies have utilized data from the IAN Project.
The IAN Project is supported by Autism Speaks, a non-profit organization dedicated to increasing awareness about the growing autism health crisis and raising funds for critical autism research.
Autism spectrum disorders (ASD) is the nation''s fastest growing developmental disorder, with current incidence rates estimated at 1 in 150 children. This year more children will be diagnosed with autism than AIDS, diabetes and cancer combined, yet profound gaps remain in our understanding of both the causes and cures of the disorder. Continued research and education about developmental disruptions in individuals with ASD is crucial, as early detection and intervention can lead to improved outcomes in individuals with ASD.
About the Kennedy Krieger Institute
Internationally recognized for improving the lives of children and adolescents with disorders and injuries of the brain and spinal cord, the Kennedy Krieger Institute in Baltimore, MD serves more than 13,000 individuals each year through inpatient and outpatient clinics, home and community services and school-based programs. Kennedy Krieger provides a wide range of services for children with developmental concerns mild to severe, and is home to a team of investigators who are contributing to the understanding of how disorders develop while pioneering new interventions and earlier diagnosis. For more information on Kennedy Krieger Institute, visit www.kennedykrieger.org