Study: Autism Risk for Siblings Higher than Previous Estimates
For families who have one child with an autism spectrum disorder (ASD), the risk of a sibling also having an ASD is substantially higher than previously thought, according to a study to be published in the September 2011 issue of Pediatrics.
About 1 in 110 U.S. children have been diagnosed with an autism spectrum disorder (ASD). In the new study, “Recurrence Risk for Autism Spectrum Disorders: A Baby Siblings Research Consortium Study,” researchers monitored 664 infants with an older biological brother or sister with ASD from early in life to 36 months. Past studies estimated the ASD recurrence risk between 3 percent and 10 percent,but this study found that the overall risk was 18.7 percent and even higher in families with more than one affected sibling, approximately 32 percent.
Male infants experienced nearly three times the risk of female infants, 26 versus 9 percent. Neither parental age, gender of the sibling, functioning level of the sibling, or birth order, was a significant predictor of ASD outcome. Study authors suggested that this knowledge can impact future genetic screening and family planning decisions