For instance, our observation of gene expression of three histone variants in 3×Tg AD mice indicated that the expression of macroH2A1 significantly increases in 6-month-old AD males but not females compared to wild type mice, whereas in both sexes H2A.X is elevated and macroH2A2 remains unchanged [61]. The gene discussed is MACROH2A2; the disease is Alzheimer disease.