SIRT2 and Huntington disease: However, the Sirt2 mutation had no overall effect on R6/2 weight loss (F(2,96) = 0.087, p = 0.917) or on the decrease in weight of R6/2 mice over time (F(6,282) = 1.902, p = 0.082), suggesting that if the Sirt2 mutation modifies weight, it does so independently of HD progression.