Autism is more likely in children with multiple autistic relatives

  • McDonald NM & al.
  • JAMA Neurol
  • 7 Oct 2019

  • International Clinical Digest
Access to the full content of this site is available only to registered healthcare professionals. Access to the full content of this site is available only to registered healthcare professionals.

Takeaway

  • 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. 

Key results

  • 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).

Study design

  • 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.

Limitations

  • Much of the cohort was excluded for incomplete data.
  • Some study site inconsistency in timing of evaluations, diagnostic confirmation process.