On a biological level, depression is characterized by increased stress sensitivity, disrupted neuroplasticity, which manifests peripherally as abnormally low serum concentrations of brain-derived neurotrophic factor (BDNF), and elevated levels of pro-inflammatory and oxidative stress markers, all of which are thought to play a role in the pathophysiology of the disease [5]. The gene discussed is BDNF; the disease is major depressive disorder.