PRNP and Creutzfeldt Jacob disease: CJD, by far the most common form, includes six major clinicopathological subtypes that are determined largely by the genotype at the methionine (M)/valine (V) polymorphic codon 129 of the PRNP gene and the type (1 or 2) of disease-associated prion protein (PrPSc) accumulating in the brain, namely MM(V)1, MM2 cortical (MM2C), MM2 thalamic (MM2T), MV2 kuru type (MV2K), VV1, and VV2 [3].