DNMT1 and Alzheimer disease: An additional link between DNA methylation and AD came from the association of the chromosome location of DNMT1 (19p13.2) with familial late-onset AD (FLOAD; Wijsman et al., 2004), although sequencing of exon 20 and 21 of DNMT1 in 364 FLOAD cases failed to identify pathogenic mutations in these regions, but only known polymorphisms with expected minor allele frequencies based on European HapMap data (Klein et al., 2013).