As shown in the original references [22, 23], the PRNP codon 129 genotype for all three patients was 129MV, and all three patients expressed one mutant PrP allele and one nonmutant allele. In the cases of Y226X and Q227X the mutant PrP was associated with 129V, whereas in the case of G131V the mutant PrP was associated with 129M. Brain tissue of all three patients had PrPSc detectable by IHC using antibody 3F4, and the Q227X and G131V patients also had protease-resistant PrP detectable by immunoblotting. Unfortunately, the Y226X patient brain was only available as formalin-fixed tissue and no immunoblotting was possible.