Compared with the HC group, plasma tau concentrations were elevated in sCJD (Dunn’s post hoc pairwise comparison test with Bonferroni correction, z = 8.7, p < 0.0001), symptomatic IPD (z = 4.5, p = 0.0001) and iatrogenic CJD (z = 3.8, p = 0.0018), but not for vCJD (z = 2.5, p = 0.1669). This evidence concerns the gene MAPT and Creutzfeldt Jacob disease.