In Creutzfeldt-Jakob disease (CJD), the type (type 1 or 2) of abnormal isoform of the prion protein (PrP(Sc)) in the brain and the genotype at codon 129 of the PrP gene are major determinants of clinicopathological phenotype.
We have compared the immunomorphological spectrum of the deposition of the disease-associated prion protein (PrP(Sc)) in the cerebral and cerebellar cortex of 32 Creutzfeldt-Jakob disease (CJD) patients with the PrP gene (PRNP) E200K mutation to 45 sporadic CJD and 14 other genetic prion disease cases.
Expression of the prion protein gene (Prnp) and production of the PrP protein are essential requirements for acquisition and spread of transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease (CJD) in humans.
Among the dozen known mutations in the PrP gene which segregate with the inherited prion diseases, only 2 mutations have been described in Israel so far: the codon 200 mutation in Creutzfeldt-Jakob disease (CJD) affected Libyan Jews, and the codon 102 mutation in 1 Jewish Gerstmann-Straussler-Scheinker (GSS) affected pedigree of German origin.
FFI and a familial type of Creutzfeldt-Jakob disease (CJD178), share the D178N mutation in the PrP gene but have distinct phenotypes linked to codon 129, the site of a methionine/valine polymorphism (129M/V).
The epidemiological data suggests a very high familial incidence of CJD in this population and a molecular genetic research elucidated that CJD segregates with a point mutation at codon 200 of the PrP gene resulting in the substitution of Lysine for Glutamate.
Furthermore, the linkage of mutations within the PRNP gene with phenotypic appearance of Creutzfeldt-Jakob disease and Gerstmann-Sträussler-Scheinker syndrome points to importance of the PrP gene.