MDD probability and these top six meta-phenotypes identified several MDD associated genes that have been suggested in the literature, whereas MDD diagnosis was not associated with them, for instance, Dopamine Receptor D3 (DRD3), 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB3), Solute Carrier Family 6 Member 4 (SLC6A4), 5-Hydroxytryptamine Receptor 2 A (HTR2A), and Coiled-Coil And C2 Domain Containing 1 A (CC2D1A), that has been consistently proven its genetic predisposition for MDD. This evidence concerns the gene SLC6A4 and major depressive disorder.