Siblings of autistic children have 20 times greater risk of autism

New research shows that younger siblings of autistic children have a much higher risk for being diagnosed with autism than the general population. It's long been known that autism runs in families, but to what degree was questionable. However, this new study, the largest of its kind to date, reveals that younger siblings of autistic child are 20 times more likely to have autism. If parents already have more than one autistic child the risk increases. In this case, around 1/3 of younger siblings are at risk for the condition. Key facts from the study:

• About 80% of autistic kids are boys, and the same held true in this study. The risk of autism was nearly three times greater in younger brothers than in younger sisters.
• Researchers still cannot figure out why this happens. They can't narrow down whether it's genes or environment, or which may play a bigger role.

As always, experts, including the ones in this study suggest that early diagnoses can help provide the best treatment for children with autism. In the case of this study, if parents already have one autistic child, it shows that it may pay off to watch carefully for autism symptoms in younger siblings. Related issues:

• Autism more common in high-tech cities
• Prenatal vitamins may help prevent autism
• Freeways may increase risk of autism

+ Recurrence Risk for Autism Spectrum Disorders: A Baby Siblings Research Consortium Study