Etiological influences on the stability of autistic traits from childhood to early adulthood: evidence from a twin study.
Mark J Taylor, Christopher Gillberg, Paul Lichtenstein and 1 others
PMID 28316769WHAT IT FOUND
Autistic traits measured by parent report in childhood and early adulthood showed moderate stability, with 85% of this consistency attributable to genetic factors.
However, genetic overlap was partial, indicating that some distinct genetic influences emerge in young adulthood.
Key findings
01The phenotypic correlation between autistic traits in childhood and early adulthood was 0.39, indicating moderate stability.
02Eighty-five percent of the stability in autistic traits from childhood to early adulthood was due to additive genetic factors, while 15% was due to nonshared environmental influences.
03The additive genetic correlation between childhood and early adulthood traits was 0.49, showing that genetic influences are not entirely consistent across development.
STILL TO COME
How it was doneWhat they found
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What it does not show
The administration method changed between time points (telephone interview in childhood vs. internet questionnaire in adulthood), which may have introduced bias or attenuated the correlation. Assessments were only made at two time points, missing potential developmental changes during adolescence. The study used a continuous trait measure (A-TAC) rather than clinical diagnoses, and lacked power to analyze the highest scoring 1% or clinical cases. Parent-report only was used at both time points, without corroboration from teachers or self-reports. The twin model fits were significantly poorer than saturated models, suggesting unmeasured complexities in the data.
The easy way to misread this
Do not interpret the moderate stability of autistic traits as evidence that clinical ASD diagnoses are static. This study measured continuous traits using a screening tool, not diagnostic categories, and found that genetic influences are not entirely consistent across development.