The social behavioral phenotype in boys and girls with an extra X chromosome (Klinefelter syndrome and Trisomy X): a comparison with autism spectrum disorder.
Kids with Klinefelter or Trisomy X show social challenges and autism features midway between typical peers and ASD, plus higher social anxiety—screen and treat anxiety specifically.
01Research in Context
What this study did
The team studied 8- to young learners with Klinefelter or Trisomy X.
They compared social skills, autism traits, and anxiety to kids with ASD and typical peers.
Tests used parent and teacher reports plus direct clinic tasks.
What they found
Extra-X kids scored worse than typical peers but better than ASD on social tasks.
Their anxiety levels were higher than both groups, especially social anxiety.
In short: social skills in the middle, anxiety on top.
How this fits with other research
Adams et al. (2020) adds that a large share of autistic kids say they feel anxious, yet adults miss half of it at school.
MacLennan et al. (2020) shows sensory hypersensitivity drives phobia-type anxiety in ASD, while hyposensitivity links to lower social anxiety—hinting that sensory work may ease some fears in extra-X youth too.
Whitehouse et al. (2014) found the same anxiety–social link in Williams syndrome, suggesting this pattern runs across several genetic conditions.
Chen et al. (2020) warns that rising autistic traits plus untreated anxiety can raise suicidality risk, so early anxiety care in extra-X kids is urgent.
Why it matters
If you serve a child with Klinefelter or Trisomy X, screen for anxiety at intake. Add CBT or social anxiety modules to your skill plans. Track progress with both social and anxiety measures—treating one may lift the other.
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02At a glance
03Original abstract
The present study aimed to gain more insight in the social behavioral phenotype, and related autistic symptomatology, of children with an extra X chromosome in comparison to children with ASD. Participants included 60 children with an extra X chromosome (34 boys with Klinefelter syndrome and 26 girls with Trisomy X), 58 children with ASD and 106 controls, aged 9 to 18 years. We used the Autism Diagnostic Interview, Social Responsiveness Scale, Social Anxiety Scale and Social Skills Rating System. In the extra X group, levels of social dysfunction and autism symptoms were increased, being in between controls and ASD. In contrast to the ASD group, the extra X group showed increased social anxiety. The effects were similar for boys and girls with an extra X chromosome.
Journal of autism and developmental disorders, 2014 · doi:10.1007/s10803-013-1860-5