It has been suggested that macroH2A1 levels are correlated withthe progression of HD: mice models have indicated increased levelsof macroH2A1 in neural regions as animals age and die.14 By studying the HD–like systems witha combination of 50% macroH2A1 and 50% canonical cores, we can mimicHD disease progression. Here, MACROH2A1 is linked to Huntington disease.