Younger siblings of those with an autistic spectrum disorder (ASD) may be at a significantly greater risk of autism than previously thought, according to a new US study.
While earlier estimates have put the risk at less than ten per cent, researchers at the University of California say that it could be as high as 19 per cent for those with one or more older brother or sister with autism. In some cases, this figure could even be as high as 26 per cent.
The study assessed 664 infants from across North America with older siblings with autism, of whom 54 were diagnosed with autism and 78 were described as having a milder form of the condition.
Incidence of autism was also found to be much higher amongst male children in the survey, with roughly 26 per cent of males compared to only nine per cent of females being diagnosed with autism.
