fatal familial insomnia
Findings
No curated finding names fatal familial insomnia yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Fatal familial insomnia (FFI) is a very rare form of prion disease characterized by subacute onset of insomnia showing as a reduced overall sleep time, autonomic dysfunction, and motor disturbances.
Definition from the Mondo Disease Ontology (MONDO:0010808), read 2026-09-29. CC BY 4.0.
- Onset and course
- Adult onset
HPO, annotations 2026-09-02
Features
34 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- MyoclonusHPOHP:0001336
- 15 of 15 reported patients
- Very frequent (80% to 99% of cases)
- AtaxiaHPOHP:0001251
- 13 of 15 reported patients
- Frequent (30% to 79% of cases)
- InsomniaHPOHP:0100785
- 13 of 15 reported patients
- Very frequent (80% to 99% of cases)
- Abnormal autonomic nervous system physiologyHPOHP:0012332
- Very frequent (80% to 99% of cases)
- DementiaHPOHP:0000726
- Very frequent (80% to 99% of cases)
- Abnormality of extrapyramidal motor functionHPOHP:0002071
- Frequent (30% to 79% of cases)
Show the remaining 22
- Emotional labilityHPOHP:0000712
- Frequent (30% to 79% of cases)
- EpiphoraHPOHP:0009926
- Frequent (30% to 79% of cases)
- HallucinationsHPOHP:0000738
- Frequent (30% to 79% of cases)
- HyperhidrosisHPOHP:0000975
- Frequent (30% to 79% of cases)
- HypertensionHPOHP:0000822
- Frequent (30% to 79% of cases)
- Laryngeal stridorHPOHP:0006511
- Frequent (30% to 79% of cases)
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- HGNC:9449HGNC:9449
- Supportive · Orphanet · Autosomal dominant · 2021