TCF7L2 and major depressive disorder: Recent genome-wide association studies27–34 on depression have implicated nine candidate genes (i.e., TNNI3 interacting kinase (Tnni3k), proopiomelanocortin (Pomc), transcription factor 7 like 2 (Tcf7l2), estrogen receptor 1, urocortin 3, serpin family D member 1, GATA-binding protein 3, T-box transcription factor 1 (Tbx1), and cholinergic receptor nicotinic alpha 3 subunit) among the 109 unique DEGs from the RIB versus CON groups.