CACNB2 and major depressive disorder: Studies have identified 317 upregulated genes in MDD patients using GWAS and candidate gene approaches, with these genes enriched in synaptic transmission pathways and protein-protein interaction networks, including the same calcium-signaling genes (CACNA1B, CACNA1E) as those found in the Psychiatric Genomics Consortium (PGC) study (CACNA1C and CACNB2) (Hori et al., 2016; Ripke et al., 2013).