HTT and neurodegenerative disease: Genetic analysis of long-distance axonal transport supports the hypothesis that interruption in axonal transport is implicated in a number of progressive neurodegenerative diseases including AD, PD, HD, Amyotrophic lateral sclerosis, etc. one common feature is, that genes linked to these diseases encode proteins transported in neuronal axon, e.g. preselin 1 and APP in AD, PINK1/Parkin in PD, Cu/Zn superoxide dismutase (SOD1) in ALS and huntingtin (Htt) in HD [112]–[114].