Our studies have established that rapamycin treatment enhances the clearance of mutant huntingtin fragments, reduces aggregate formation and protects against toxicity in cell, Drosophila and mouse models of Huntington's disease (HD) (Berger et al., 2006; Ravikumar et al., 2006; Sarkar et al., 2009; Webb et al., 2003). This evidence concerns the gene HTT and Huntington disease.