HCG9 and major depressive disorder: Again, the largest blood–brain concordant signals that were shared between BIP, SCZ, and MDD were in the MHC region, such as BTN3A2, H2AC13, ZNF389, and ZSCAN12L1 for the brain and BTN3A2, DDR1, DPCR1, GTF2H4, H2AC13, HCG9, HIST1H4D, HLA-B, MSH5, PBX2, SFTA2, TRIM15, TRIM26, TRIM27, TRIM31, TRIM40, TUBB, and VARS2 for blood.