(3) The abundance of <i>Mogibacterium</i> was significantly correlated with scores on the 24-item Hamilton Depression Scale (HAMD-24) and the Self-Rating Depression Scale, as well as with serum levels of brain-derived neurotrophic factor (BDNF), nerve growth factor, and vascular endothelial growth factor (VEGF) in MDD patients. The gene discussed is BDNF; the disease is major depressive disorder.