As aproof of the structural flexibility of this segment, which can be also inferredfrom an analysis of PrP pathological variants [52–54], the D178N CJD-associated variant, that is the most important mutation occurring in CJD, is not even able to assume a fully helical structure, like that found in PrPC, in an α-inducing environment. This evidence concerns the gene PRNP and Creutzfeldt Jacob disease.