关键词: 四氢生物蝶呤, 代谢, 四氢生物蝶呤缺乏症, 高苯丙氨酸血症

Abstract: Tetrahydrobiopterin is involved in regulating the dynamic balance of many neurotransmitters，hormones and inflammatory factors in the body. It is an important coenzyme in the metabolic pathway of phenylalanine. Tetrahydrobio-pterin deficiency leads to reduced activity of phenylalanine hydroxylase， resulting in neuropsychiatric diseases and hyperphenylalaninemia. The common clinical manifestations of tetrahydrobiopterin deficiency are psychomotor retardation，abnormal muscle tone and convulsions. If there is no timely treatment，the prognosis is poor. This article describes the metabolism of tetrahydrobiopterin and the diagnosis and treatment of tetrahydrobiopterin deficiency，in order to improve knowledge and understanding of the disease，provide reference for clinical diagnosis and treatment，and further improve the outcome of the patients.

Key words: tetrahydrobiopterin（BH4）, metabolism, tetrahyd-robiopterin deficiency, hyperphenylalaninemia