Additionally, the psychotic symptoms significantly impaired the patient’s ability to function socially and academically, meeting Criterion E. In this context, this case meets all the diagnostic criteria for a psychotic disorder due to another medical condition, i.e., cerebral venous thrombosis due to primary thrombophilia associated with protein S deficiency and the MTHFR p.Ala222Val variant. The gene discussed is MTHFR; the disease is hyperinsulinemic hypoglycemia, familial, 4.