For example, in AD patients and animal AD models some genes are hypermethylated (MTHFR, APOEε4, MAPT, SORBS3, Tau), while others are hypomethylated (CREB5, S100A2, PP2A, BACE, PS1) or exhibit no significant difference (APP) [35,129]. The gene discussed is PTPA; the disease is Alzheimer disease.