The largest study to date conducted on siblings of children with autism found that there is a higher chance of being diagnosed with the disorder than previously thought. On average, 1 in 110 children born today may have ASD reports The U.S. Centers for Disease Control and Prevention (CDC).

The study advises Pediatricians to be vigilant in monitoring younger siblings of children with autism spectrum disorder (ASD) in order to better treat and support it if the diagnosis have been missed.

Autism Spectrum Disorder (ASD) is a group of developmental disabilities that affects the child's ability to communicate, and have behavioral challenges that affect learning and social interactions with others.

"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.

Using the gold standard diagnostic methods and comprehensive assessment by expert researchers, the study evaluated 664 sibling infants from 12 U.S sites and 12 Canadian sites. They evaluated children as early as 6 months of age, before they showed any symptoms and monitored them until the age of 36 months. At the end of around 36 months, doctors tested each of the kids for signs of autism. Of the 132 siblings, or roughly 20 percent, had developed autism spectrum disorder (ASD), reported the Journal Pediatrics.

"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," said Dawson.

There is strong evidence that genetic factors play a critical role in vulnerability for developing autism.

"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."