GAD1 and Huntington disease: Among these, the Gad1 and Gad2 genes, which encode enzymes that catalyze the synthesis of GABA, the β4 subunit of the channel MSN voltage-gated sodium Scn4b [47,48] and Slc7a11, which is the astrocyte glutamate transporter, indicate an excitatory/inhibitory balance that is deregulated in this model from early stages of HD [46].