Our study also found that Gsto2 expression decreased with age in TrkbPenk-KO mice (Fig. 3f and related source data), which is consistent with the results of a previous study48 reporting GSTO2 downregulation in iSPNs in post-mortem analysis of brains from patients with grade 2–4 HD, using RNA-seq analysis (Fig. 8g). This evidence concerns the gene GSTO2 and Huntington disease.