HTT and amyotrophic lateral sclerosis: Both amyotrophic lateral sclerosis (ALS) and Huntington mutant mouse models, i.e., superoxide dismutase 1 (SOD1)- and huntingtin (htt)-mediated, respectively, show defective astrocytic glutamate transporters, eventually leading to extracellular glutamate accumulation and neuronal death through excitotoxicity 185, 186.