SIRT6 and Huntington disease: The relatively low mRNA levels observed for Sirt1, as well as for Sirt6 and Sirt7, in brain regions from 3 and 24 month old rats relative to their expression levels in the late embryonic and early postnatal times were somewhat surprising, as Sirt1 has been strongly implicated as a neuroprotective factor in models of Huntington's disease (Jeong et al., 2011), Multiple sclerosis (Shindler et al., 2007; Khan et al., 2014), stroke (Yan et al., 2013) and Alzheimer's disease (Qin et al., 2006).