The analysis reported a negative Z-score (−1.213) for the Opioid Signalling Pathway, indicating an inactivation of this pathway in the striatum of Huntington’s disease mice, likely due to changes in the phosphorylation profiles of the proteins involved (ADCY5, ARRB1, CACNA1C; E; B1; B2; B4; G2; G4, Calm1, CAMK2A, GNAO1, GNG12, GRIN2A, ITPR1, PRKCB, PRKCE, RAF1, RASD2, RGS8 and RGS9, RPS6KA5, TH). This evidence concerns the gene GRIN2A and juvenile Huntington disease.