Washington, August 15: Younger siblings of children with autism have a 19 percent chance of developing the disorder, a new study has found.
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 researchers said.
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.
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.
“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.
The study was recently published in the journal Pediatrics. (ANI)