2D:4D Ratio and Autism Spectrum Disorder in Brunei Darussalam.
Shirley H F Lee, Syahiirah Abd Aziz, Mawarni Hamid and 3 others
PMID 33570687WHAT IT FOUND
In Bruneian children, a lower finger length ratio on the left hand was associated with autism in boys, but not girls.
The study was small and cannot be used to diagnose autism or guide therapy.
Key findings
01For every 1 standard deviation increase in the left-hand 2D:4D ratio, the odds of an autism diagnosis decreased in males (Adjusted OR = 0.57, 95% CI: 0.31–0.96; p = 0.044).
02No significant association was found between the 2D:4D ratio and autism diagnosis in females for either the left or right hand.
03There was no significant difference in median 2D:4D ratios between the autism and typically developing groups for either hand.
STILL TO COME
How it was doneWhat they found
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What it does not show
The sample size was small, particularly for females (n = 19), limiting the ability to detect associations in this group. Handedness was not recorded, which is known to influence 2D:4D ratios and may confound the results. The study did not account for ASD subtype or severity, which might explain some of the heterogeneity in findings. The non-response rate was high (45-53%), and non-responders might differ systematically from participants. Measurements were taken from photographs rather than direct contact, which may introduce error, although rater agreement was high.
Declared interests
Funded by Universiti Brunei Darussalam. No other conflicts of interest are reported.
The easy way to misread this
Do not use the 2D:4D ratio as a diagnostic tool or to assess prognosis. The study was small, underpowered for females, and the association found in males was for the left hand only, contradicting previous literature that often identifies the right hand. The authors state these findings require validation before any clinical application.