CACNA1C and major depressive disorder: Our main findings were that CACNA1C rs1006737 genotypes and TLEs were independently associated with MDD, and that CACNA1C rs1006737 genotypes significantly modified the risk conferred by TLEs for MDD; moreover, a dose-response relationship was found to exist between CACNA1C rs1006737 genotypes and TLEs in MDD, with the meta-analysis confirming an interaction between these variables.