This is possible in patients who are homozygous for methionine at codon 129 of the PRNP gene (129MM), but show a molecular prion strain type and kuru‐plaque pathology akin to prion disease patients with valine at codon 129 (i.e. 129MV or 129VV), suggestive of the pathogen originating from a patient with at least one PRNP 129V allele 50, 51. Here, PRNP is linked to prion disease.