Triple X syndrome (TXS) is caused by aneuploidy of the X chromosome and is associated with impaired social functioning in children; however, its effect on social functioning and emotion recognition in adults is poorly understood.

The aim of this study was to investigate social functioning and emotion recognition in adults with TXS.

This cross-sectional cohort study was designed to compare social functioning and emotion recognition between adults with TXS (n = 34) and an age-matched control group (n = 31). Social functioning was assessed with the Adult Behavior Checklist and Social Responsiveness Scale for Adults. Emotion recognition was assessed with the Emotion Recognition Task in the Cambridge Neuropsychological Test Automated Battery. Differences were analysed by Mann-Whitney U-test.

Compared with controls, women with TXS scored higher on the Adult Behavior Checklist, including the Withdrawn scale (P < 0.001, effect size 0.4) and Thought Problems scale (P < 0.001, effect size 0.4); and higher on the Social Responsiveness Scale for Adults, indicating impaired social functioning (P < 0.001, effect size 0.5). In addition, women with TXS performed worse on the Emotion Recognition Task, particularly with respect to recognising sadness (P < 0.005, effect size 0.4), fear (P < 0.01, effect size 0.4) and disgust (P < 0.02, effect size 0.3).

Our findings indicate that adults with TXS have a higher prevalence of impaired social functioning and emotion recognition. These results highlight the relevance of sex chromosome aneuploidy as a potential model for studying disorders characterised by social impairments such as autism spectrum disorder, particularly among women.