Autistic behaviors among girls with fragile X syndrome.
Girls with fragile X show more autistic behaviors driven by anxiety and linked to a smaller cerebellar vermis.
01Research in Context
What this study did
The team compared girls with fragile X to girls without the condition.
They looked at how many autistic traits each group showed.
Doctors also measured anxiety levels and took brain scans to see if parts of the brain were smaller or larger.
What they found
Girls with fragile X showed more autistic behaviors than the control girls.
Higher anxiety went hand in hand with certain behaviors like hand flapping.
A smaller rear part of the cerebellum was linked to these behaviors, hinting at a brain basis.
How this fits with other research
Casey et al. (2009) followed younger fragile X girls over time and found that even mild autistic signs predicted slower development, extending the 1997 snapshot into a trajectory.
Sullivan et al. (2007) gave parents and teachers a list of anxiety red flags—staring, task refusal, arguing—to watch for in fragile X kids, turning the 1997 lab finding into everyday practice.
Olsson et al. (2001) saw the same autism–poor outcome link in fragile X boys, yet FMRP protein levels mattered less than behavior, showing the pattern holds across sexes even though the 1997 girls also tied behaviors to anxiety and brain size.
Why it matters
If you assess a girl with fragile X, score both autism traits and anxiety; they travel together.
Note any repetitive or avoidant behaviors—these may signal worry she cannot voice.
Share Kelly’s parent-friendly checklist so families can track signs at home.
Finally, remember the cerebellum finding: motor-based interventions might ease both anxiety and autistic behaviors in this group.
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02At a glance
03Original abstract
Reports of autistic behaviors were examined for 30 school-age girls with fragile X (fraX) and 31 age- and IQ-matched controls through a structured interview administered to each girl's parent(s). IQ scores were obtained for each participant; anxiety, neuroanatomical, and molecular-genetic data were derived for girls with fraX. Girls with fraX had significantly more autistic behaviors than controls. These behaviors were qualitatively similar to those reported for boys with fraX, but were not correlated with IQ. Anxiety in girls with fraX was positively correlated with abnormal social and communication behaviors; posterior cerebellar vermis area was negatively correlated with measures of communication and stereotypic/restricted behaviors. Severity of stereotypic/restricted behaviors was negatively correlated with the prevalence of active non-fraX chromosomes. Thus anxiety and posterior cerebellar area measures had distinct associations with subsets of autistic behaviors; these associations may have important implications for understanding the neurobiology of autism.
Journal of autism and developmental disorders, 1997 · doi:10.1023/a:1025857422026