Some 10–15% of cases are associated with autosomal dominant pathogenic sequence variations in the prion protein gene (PRNP), while acquired forms are rare and are caused by the transmission of infective material from human to human (Kuru and iatrogenic Creutzfeldt-Jakob disease (iCJD)) or from cattle to human (variant CJD) [4]. This evidence concerns the gene PRNP and iatrogenic Creutzfeldt-Jakob disease.