A Sod1 SNP from intron 3 (Table 2), of no known function, also showed a highly significant association with prion disease incubation time (P<0.0001, Kruskal-Wallis non-parametric ANOVA) where the GG genotype was associated with a short incubation time (132+4.7) and the AA genotype with a longer incubation time (149+1.5). The gene discussed is SOD1; the disease is prion disease.