About Fragile X Syndrome
Fragile X syndrome is the most common inherited cause of intellectual disability and the leading single-gene cause of autism spectrum disorder, caused by CGG trinucleotide repeat expansion in the FMR1 gene leading to silencing of FMRP protein expression. Clinical features include intellectual disability, social anxiety, repetitive behaviors, large ears, macroorchidism in males, and hyperarousal. Females are typically less severely affected. Premutation carriers (55-200 repeats) are at risk for fragile X-associated tremor/ataxia syndrome (FXTAS).
Common Clinical Features
Clinical Trial Eligibility Tips
What to know before applying to Fragile X Syndrome trials.
Full mutation CGG repeat count (>200 repeats) confirmed by Southern blot or PCR is the diagnostic requirement for FXS trials
Premutation carriers (55-200 repeats) qualify for FXTAS trials — these are distinct populations from full mutation FXS trials
Cognitive and behavioral endpoints (VABS, SNAP-IV, ABC-C) are standard baseline and outcome assessments
FMRP-targeting trials (metformin, mGluR5 antagonists) may require washout from prior investigational therapies
Patient Resources
Natural History Registry
Fragile X Online Registry with Accessible Research Database (FORWARD)
Join registry ↗Find recruiting Fragile X Syndrome trials
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