The initial model included a multitude of candidate predictors in the fields of sex, age group, race, education level, marital status, ALB, PIR, ALT, AST, alkaline phosphatase, urea nitrogen, serum calcium, CPK, TC, fasting plasma glucose, creatinine, serum iron, serum phosphorus, total bilirubin, uric acid, TG, smoking status, diabetes, stroke, hypertension, high cholesterol, glycosylated hemoglobin, HDL, depression, sleep disorder, and aspirin use. The gene discussed is PIK3C2A; the disease is major depressive disorder.