Minor physical anomalies in ASD and ADHD: a systematic review and meta-analysis

20/08/2026

AI Summary

MPAs significantly elevated in ASD and ADHD compared with controls (pooled Hedges' g = 0.72, 95% CI 0.56-0.89).
No significant difference between ASD and ADHD; disorder-specific effects (ASD g = 0.69, ADHD g = 0.77) support transdiagnostic marker of early developmental perturbation.
ASD showed stronger craniofacial effects, notably ear and palate features; ADHD analyses indicated small-study effects, yet sensitivity analyses preserved conclusions.

Nord J Psychiatry. 2026 Aug 20:1-10. doi: 10.1080/08039488.2026.2720122. Online ahead of print.

ABSTRACT

BACKGROUND: Minor physical anomalies (MPAs) are subtle morphological variants that may reflect atypical prenatal development. Elevated MPAs have been reported in autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), but findings have been inconsistent.

METHODS: We systematically searched PubMed, Web of Science, and grey-literature sources for case-control studies published through December 2025 that reported total MPA scores in ASD or ADHD versus typically developing controls. Pooled effect sizes were calculated as Hedges’ g using random-effects models with restricted maximum likelihood estimation. Shared control groups were handled by sample splitting. Heterogeneity, subgroup and moderator effects, and small-study effects were examined.

RESULTS: Twelve ASD studies and eight ADHD studies met inclusion criteria. Across disorders, MPAs were significantly elevated relative to controls (pooled g = 0.72, 95% CI 0.56-0.89). Disorder-specific pooled estimates were significant for both ASD (g = 0.69) and ADHD (g = 0.77), with no significant difference between disorders (Q_bet = 0.22, p = 0.64). In ASD, effects were stronger for craniofacial anomalies than for peripheral anomalies, and item-level syntheses highlighted several ear- and palate-related features. In ADHD, evidence of small-study effects suggested possible overestimation, although conclusions remained robust in sensitivity analyses.

CONCLUSIONS: MPAs are reliably elevated in both ASD and ADHD. Current case-control evidence supports MPAs as a transdiagnostic marker of early developmental perturbation rather than a feature that strongly differentiates between these disorders.

PMID:42619500 | DOI:10.1080/08039488.2026.2720122

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