Cognition, academic achievement, and adaptive behavior in school-aged girls with fragile X syndrome.
Girls with fragile X show hidden math, attention, and working-memory gaps even when their words and daily skills look fine.
01Research in Context
What this study did
Howard et al. (2023) compared 28 school-age girls with fragile X syndrome to 28 girls matched on verbal IQ. They gave tests for nonverbal reasoning, math, attention, working memory, and everyday adaptive skills.
The team wanted to see which thinking skills were weaker than expected once talking ability was held constant.
What they found
Girls with FXS scored far below their verbal-IQ matches in math, nonverbal puzzles, sustained attention, and working memory. Yet parents rated their daily living, social, and communication skills as no different.
In short, big classroom-thinking gaps sat beside average-looking life skills.
How this fits with other research
The math weakness lines up with Bae et al. (2015) and Eussen et al. (2016), who also found lower math scores in autistic children matched on IQ. It seems math is a fragile skill across developmental disorders.
Myers et al. (2018) and Terroux et al. (2025) show everyday executive function predicts adaptive gains in autism. L et al. extend that link to FXS girls: weak working memory plus flat adaptive scores echo the same EF-adaptive pattern.
Maehler et al. (2016) report that working memory, not IQ, drives school success in mixed-ID samples. L et al. confirm this in FXS girls, strengthening the case for WM screening before writing academic goals.
Why it matters
When a girl with FXS talks well, her report card can still crash in math and problem solving. Add brief working-memory and nonverbal tests to your assessment. Then write goals that teach counting strategies, visual scaffolds, and self-monitoring rather than assuming adaptive delays. Target the cognitive bottleneck, not just the academic symptom.
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02At a glance
03Original abstract
BACKGROUND: Fragile X syndrome (FXS) is the leading monogenic cause of intellectual disability and autism in males and females. Females with FXS typically display a milder cognitive phenotype than males, despite experiencing significant developmental, behavioral, and social-emotional issues. AIMS: To measure and distinguish the cognitive-behavioral profile of girls with FXS relative to verbal IQ-matched peers. METHODS AND PROCEDURES: Ninety-seven participants (NFXS=55, Ncomparison=42) six to 16 years of age completed assessments evaluating cognition, academic achievement, and adaptive behavior. The comparison group consisted of age-, sex-, and verbal IQ-matched peers. OUTCOMES AND RESULTS: Consistent with previous studies, the FXS group demonstrated mean cognitive skills, academic achievement, and adaptive behavior in the borderline to low average range. On average, the FXS group showed poorer nonverbal reasoning, visual pattern recognition, verbal abstraction, math abilities, attention, inhibitory control, and working memory than the comparison group. There were no significant group differences in adaptive behavior. Different patterns of associations between cognition and selected outcomes emerged in each group. CONCLUSIONS AND IMPLICATIONS: Results highlight the importance of identifying specific cognitive-behavioral profiles in girls with FXS to inform more targeted interventions for optimizing outcomes and quality of life in this population.
Research in developmental disabilities, 2023 · doi:10.1002/ajmg.a.31388