- Infants who have more than 1 autistic relative are likelier themselves to be diagnosed with autism in their first 3 years.
- Having 1 older sibling with autism increased the likelihood by 43%, and having 2 or more increased it by 67%.
Why this matters
- These findings from the "baby sibs" consortium study confirm the high genetic contribution to autism.
- The authors say that the results warrant early screening and prompt referral to access early intervention for optimal outcomes.
- Autism rates were higher among children born into multiplex vs single-incidence families:
- 36.3% vs 16.1% (95% CI, 9%-31%; P<.001>
- Autism features did not differ between children with 1 vs multiple autistic family members.
- Cognitive abilities were lower at age 3 years among children who were not themselves autistic but who had multiple autistic family members (P=.02).
- Longitudinal, prospective 11-site Baby Siblings Research Consortium database study, with 435 infants born into families with autistic children, covering 2003-2015.
- Funding: NIH; others.
- Much of the cohort was excluded for incomplete data.
- Some study site inconsistency in timing of evaluations, diagnostic confirmation process.