CLEC4D and major depressive disorder: MDD module genes were found enriched in ST3-SC and ST1-TP for immune-related pathways (viral process GO:0016032 praw = 1.0 × 10− 8, stimulatory C-type lectin receptor signaling pathway GO:0002223 praw = 2.5 × 10− 12, and antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent GO:0002479 praw = 1.8 × 10− 9), suggesting the immune disturbance in brain TP and SC region could be the underlying etiology of MDD (Fig. 4d).