HTT and Huntington disease: In particular, HD rodent models carrying more copies of full-length HTT, such as BACHD mice and YAC mice, display increased body weight [11,12,13,14], whereas models expressing a fragment of mutant HTT (mHTT) or HD knock-in models show decreased body weight due to the depletion of full-length wild type HTT (wtHTT) [15,16,17,18,19].