SOD1 and amyotrophic lateral sclerosis: While the promoters of SOD1, VEGF, and GLT1 genes have been found to be unmethylated in ALS patients [77, 78], hypermethylation of GRN promoter has been reported in FTD subjects and the observed lower mRNA levels lend support to its correlation with GRN haploinsufficiency and FTD pathogenesis [77, 78].