The APOE ε4 allele distribution (APOE ε4+) did not differ between CJD groups classified according to the histotype (MM(V)1 16.4% vs VV2 18.0% vs MV2K 10.5% vs Other 4.1%, p = 0.398), PrPSc type (type 1 18.3% vs type 1 + 2 10.9% vs type 2 14.2%, p = 0.202) or PRNP codon 129 genotype (ε4+: MM 16.0% vs MV 10.0% vs VV 18.8%, p = 0.393) (Additional file 7. This evidence concerns the gene PRNP and Creutzfeldt Jacob disease.