What is the recurrence rate of autism spectrum disorder (ASD) in siblings of children with ASD?
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Studies of sibling recurrence done in the past decades usually reported between 2-6% of younger siblings of children with autism were eventually diagnosed with autism. However, it was thought that these numbers may be an underestimate, because they included low numbers of families and looked at just autism in the child and the younger sibling.
Because of the elevated risk of autism in younger siblings, new research designs have allowed for prospective, longitudinal research of individuals “at risk” for autism – that is they have an older sibling with an autism diagnosis. Autism Speaks supports a consortium of these researchers known as the High Risk Baby Siblings Research Consortium or BSRC. Using this design, the recurrence of autism as well as other disorders, including language problems, can be ascertained. Recent reports have indicated that about 10-15% of younger siblings of children with autism are diagnosed with an ASD. In addition,, a recently published study by a BSRC investigator working together with the Interactive Autism Network (IAN) found that 20% of siblings (without ASD) had delayed language development. Together, this adds to evidence that autism and related developmental delays in language have a genetic component. It is important to keep in mind that the information about ASD recurrence risk rates cited in this article are based on population-based statistics. The ASD recurrence risk rates for individual families vary.
Parents with who have a child with ASD who are concerned that a sibling may be showing symptoms of ASD should bring their concerns to their pediatrician or primary health care provider. Other resources include the following:
- Visit the Autism Speaks website more information about early signs of autism http://www.autismspeaks.org/whatisit/learnsigns.php
- Participate in a research study that provides early screening and diagnosis of autism will allow you to work with clinicians trained to provide identification and intervention of autism for as young as 12 months of age. Such research projects include the EARLI study: www.earlistudy.com and the IBIS network www.ibis-network.org. A full list of the BSRC can be found here: http://www.autismspeaks.org/science/research/initiatives/babysibs.php
- Visit the Autism Speaks Resource Guide to find a physician or specialist near you http://www.autismspeaks.org/community/resources/index.php