Fatal familial insomnia (FFI) is an inherited prion disease that shares characteristics of Creutzfeldt-Jakob disease (CJD); FFI and CJD are considered by some researchers to be extremes of a phenotypic spectrum. Experiments in Drosophila are described in the human disease model reports Creutzfeldt-Jakob disease, familial (FBhh0000791) and prion diseases (FBhh0000185).
Using mouse and hamster genes, variants associated with Creutzfeldt-Jakob disease (E200K in the human PRNP gene, see Mmus\PrnpCJD.3F4.UAS, Maur\PrpCJD.UAS) and fatal familial insomnia (D178N in the human PRNP gene, see Mmus\PrnpFFI.3F4.UAS, Maur\PrpFFI.UAS) have been characterized in flies.
[updated Feb. 2019 by FlyBase; FBrf0222196]
The human prion diseases occur in inherited, acquired, and sporadic forms. Approximately 15% are inherited and associated with coding mutations in the PRNP gene. Inherited prion diseases include familial Creutzfeldt-Jakob disease (CJD; MIM:123400), Gerstmann-Straussler disease (GSD; MIM:137440), and fatal familial insomnia (FFI; MIM:600072). Acquired prion diseases in humans include iatrogenic CJD, kuru (MIM:245300), and variant CJD (vCJD). Variant CJD is believed to be acquired from cattle infected with BSE. The majority of human cases of prion disease occur as sporadic CJD (sCJD) (Collinge et al., 1996, pubmed:8878476; Parchi et al., 2000, pubmed:10963679; Hill et al., 2003, pubmed:12764055). [from MIM:176640; 2016.03.01]
[FATAL FAMILIAL INSOMNIA; FFI](https://omim.org/entry/600072)
[PRION PROTEIN; PRNP](https://omim.org/entry/176640)
Fatal familial insomnia (FFI) is clinically characterized by insomnia with or without a diurnal dreaming state, hallucinations, delirium, and dysautonomia preceding motor and cognitive deterioration. [from MIM:600072; 2018.22.02]
There is considerable clinical and pathologic overlap between FFI and Creutzfeldt-Jacob disease (CJD); thus, FFI and CJD may be viewed as extremes of a phenotypic spectrum (summary by Zarranz et al., 2005; 16227536). [from MIM:600072; 2018.22.02]
Fatal familial insomnia (FFI) is associated with mutation in the prion protein gene (PRNP); it exhibits autosomal dominant inheritance. [from MIM:600072; 2018.22.02]
Variants implicated in FFI have also been found in patients diagnosed with Creutzfeldt-Jacob disease (CJD), supporting the view that FFI and CJD are extremes of a phenotypic spectrum (Zarranz et al., 2005; 16227536). [from MIM:600072; 2018.22.02].
The protein encoded by PRNP is a membrane glycoprotein that tends to aggregate into rod-like structures. Its primary physiological function is unclear; it may be required for neuronal myelin sheath maintenance. [Gene Cards, PRNP; 2018.04.19]
