TCF4 and major depressive disorder: Huo et al. [49]and Wray et al. [21] employed meta-analysis and genome-wide association analysis (GWAS) identified a large number of candidate genes related to MDD, including Solute carrier family 25 member 37 (SCL25A37), Raftlin family member 2 (RFTN2), Transcription Factor 4 (TCF4), and Butyrophilin subfamily 1 member A1 (BTN1A1) genes.