While the incidence of vCJD has been in decline in the UK since its peak in 2000, all definite diagnoses up to 2016 have been in patients with a particular prion protein (PrP) genotype (MM) at polymorphic codon 129, where either methionine (M) or valine (V) is encoded [3]. Here, PRNP is linked to variant Creutzfeldt-Jakob disease.