In the HD model, reduced expression and deacetylase activity of SIRT3, which in turn prevents the deacetylation of LKB1 and SOD2, leading to a decrease in the level of NAD+, defects in mitochondrial biogenesis and accumulation of ROS.532 However, the overexpression of SIRT1 displays protection against abnormal motor function, cortical and striatal atrophy and loss of striatal neurons in the transgenic HD mice via regulating mitochondrial function.531 Both SIRT1 and SIRT3 exert their function through PGC-1α, which acts as a modifier in HD and ALS patients and other models. The gene discussed is STK11; the disease is Huntington disease.