METTL9 and major depressive disorder: Moreover, 58 differentially regulated transcripts identified in this study overlapped candidates from three gene expression studies of MDD [45, 109] (Supplementary Tables TS24), a vast majority of which were altered in multiple regions beyond the single region profiled in the respective human studies (e.g. Arhgef25, Kmt2a, Mettl9, Rhoa, Mgat4c).