Non-ASD outcomes at 36 months in siblings at familial risk for autism spectrum disorder (ASD): A baby siblings research consortium (BSRC) study.
Tony Charman, Gregory S Young, Jessica Brian and 22 others
PMID 27417857WHAT IT FOUND
High-risk siblings who did not meet autism criteria at 36 months were more likely than controls to have mild-to-moderate global developmental delay and elevated autism symptom scores.
Their language delay rates were not higher.
Key findings
01At 36 months, mild-to-moderate developmental delay was reported in 10.59% of high-risk siblings without ASD and 3.38% of low-risk controls.
02Mild-to-moderate language delay rates did not differ: 6.87% in high-risk siblings without ASD and 5.07% in low-risk controls.
03Autism symptom scores at or above the study's elevated cut-off were more common in high-risk siblings (250/859, 29.10%) than in low-risk controls (80/393, 16.91%).
STILL TO COME
How it was doneWhat they foundWhat it means for OTsWhat it means for SLPs
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What it does not show
The autism interview and adaptive behaviour measures were available only for a subsample, and whether they were completed was related to risk group, autism symptom score, and site. The sample had high maternal education, with about 70% of high-risk mothers and about 80% of low-risk mothers educated to college level, so it may not represent broader families. Mild delay was defined as scores more than one standard deviation below average; with stricter clinical thresholds, developmental delay and language delay in high-risk siblings were 2.79% and 1.40%. The high-risk and low-risk groups were purposively sampled, so the same elevated autism symptom score may not mean the same thing in the two groups. Some sites did not provide all primary assessment data, so the analysed sample was smaller than the original dataset. Age at first assessment and maternal education differed between groups and were also associated with outcomes.
Declared interests
Dr Zwaigenbaum receives operating funds but not honoraria from SynapDx. Dr Charman receives royalties from Guilford Press and Sage Publications. The other listed authors declare no competing interests.
The easy way to misread this
Do not conclude that high-risk siblings without autism have elevated language delay. The rates of mild-to-moderate language delay did not differ between high-risk siblings and low-risk controls.