Tas, CEssen-Danaci, A2024-07-182024-07-181017-7833http://akademikarsiv.cbu.edu.tr:4000/handle/123456789/2133Although schizophrenia is known as a late adolescence or early adulthood disorder psychotic symptoms can be seen in children. Schizophrenia which begins before 17-18 years of age is named as. early onset schizophrenia and before age of 13 is named as very early onset schizophrenia. Studies on organic etiology of schizophrenia were increased after the description of early onset schizophrenia. It was determined that cerebral trauma, infections, demyelinization diseases, endocrinopathies, systemic diseases, vitamin deficiencies, drugs, epilepsy, sex chromosome abnormalities, and diseases with Mendelian inheritance can cause clinical symptoms like schizophrenia. In this article a homocystinuria case which was diagnosed as early onset schizophrenia according to its onset is presented.TurkishMETHYLENETETRAHYDROFOLATE REDUCTASEHOMOCYSTEINEDIARRHEARISKArticle