Fatal familial insomnia: genes and variants
Fatal familial insomnia is linked to 1 analyzed protein (PRNP). 3 DNA variants are known to cause it; 2 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 Fatal familial insomnia
PRNP: Major prion protein
Its normal cellular form is enriched in the nervous system, but misfolding into self-propagating conformations can template further protein conversion. This process causes prion diseases, while germline pathogenic variants underlie inherited Creutzfeldt-Jakob disease, Gerstmann-Straussler-Scheinker disease, and fatal familial insomnia.
3 disease-causing and 2 uncertain variants in PRNP are linked to Fatal familial insomnia.
Known disease-causing variants in Fatal familial insomnia
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| PRNP V180I | 180 | Interaction with GRB2, ERI3 and SYN1 | Disease-causing (★) |
| PRNP D178N | 178 | Interaction with GRB2, ERI3 and SYN1 | Disease-causing |
| PRNP M129V | 129 | Interaction with GRB2, ERI3 and SYN1 | Disease-causing |
Same protein, different disease
- Huntington disease-like 1 is also caused by PRNP variants; they fall mostly in different places as the Fatal familial insomnia variants (13 disease-causing).
- Gerstmann-Straussler-Scheinker syndrome is also caused by PRNP variants; they fall mostly in different places as the Fatal familial insomnia variants (8 disease-causing).
- Spongiform encephalopathy with neuropsychiatric features is also caused by PRNP variants; they fall mostly in different places as the Fatal familial insomnia variants (4 disease-causing).
Diseases related to Fatal familial insomnia
- Huntington disease-like 1, also linked to PRNP
- Gerstmann-Straussler-Scheinker syndrome, also linked to PRNP
- Inherited Creutzfeldt-Jakob disease, also linked to PRNP
- Spongiform encephalopathy with neuropsychiatric features, also linked to PRNP
- Dementia, also linked to PRNP
- Kuru, susceptibility to, also linked to PRNP
Frequently asked questions
Which genes are linked to Fatal familial insomnia?
In CATVariant, Fatal familial insomnia is linked to 1 analyzed protein: PRNP (Major prion protein).
How many genetic variants are linked to Fatal familial insomnia?
7 variants: 3 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 2 are of uncertain significance or have conflicting reports.
Which uncertain variants in Fatal familial insomnia 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.
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