A significant association was found in the dominant model for rs10494366 (T/T vs. G/T + G/G: OR = 0.58, 95% CI = 0.39–0.87, p = 0.009) and rs12143842 (C/C vs. C/T + T/T: OR = 0.56, 95% CI = 0.37–0.58, p = 0.006) polymorphisms, indicating the dominant model of NOS1AP might decrease the risk of MetS in schizophrenia patients. The gene discussed is NOS1AP; the disease is schizophrenia.