Fragile X syndrome: genes and variants
Fragile X syndrome is linked to 1 analyzed protein (FMR1). 1 DNA variants are known to cause it; 7 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Fragile X syndrome
FMR1: Fragile X messenger ribonucleoprotein 1
Its FMRP product binds neuronal RNAs and regulates their transport and local translation at synapses. Full CGG-repeat expansion silences the gene and causes fragile X syndrome, while premutation alleles can cause tremor-ataxia syndrome or primary ovarian insufficiency.
1 disease-causing and 7 uncertain variants in FMR1 are linked to Fragile X syndrome.
Known disease-causing variants in Fragile X syndrome
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| FMR1 I304N | 304 | KH 2 | Disease-causing |
Diseases related to Fragile X syndrome
- Premature ovarian failure, also linked to FMR1
Frequently asked questions
Which genes are linked to Fragile X syndrome?
In CATVariant, Fragile X syndrome is linked to 1 analyzed protein: FMR1 (Fragile X messenger ribonucleoprotein 1).
How many genetic variants are linked to Fragile X syndrome?
13 variants: 1 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 7 are of uncertain significance or have conflicting reports.
Which uncertain variants in Fragile X syndrome look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
Download every variant as CSV · Browse all diseases · Methods · About the Center