In addition to genetic mutation and histopathological hallmarks, the critical determinant of HD is the degeneration of medium size spiny neurons (MSNs) expressing γ-aminobutyric acid (γ-GABA), N-methyl-D-aspartic acid receptors (NMDARs) and dopamine and cAMP regulated phosphoprotein of 32 kDa (DARPP-32). Here, PPP1R1B is linked to Huntington disease.