This gene encodes a member of the GTP cyclohydrolase family. The encoded protein is the first and rate-limiting enzyme;in tetrahydrobiopterin (BH4) biosynthesis, catalyzing the conversion of GTP into 7,8-dihydroneopterin triphosphate.;BH4 is an essential cofactor required by aromatic amino acid hydroxylases as well as nitric oxide synthases. Mutations;in this gene are associated with malignant hyperphenylalaninemia and dopa-responsive dystonia. Several alternatively;spliced transcript variants encoding different isoforms have been described; however, not all variants give rise to a;functional enzyme.
GCH1; GTP cyclohydrolase 1; dystonia 14 , DYT5, DYT14, GCH; dopa responsive dystonia; DYT5a; GTPCH1; GTP-CH-I; dystonia 14; GTP cyclohydrolase I; guanosine 5-triphosphate cyclohydrolase I; GCH; DYT5; DYT14; HPABH4B; GTP-CH-1; GTP cyclohydrolase 1 (dopa-responsive dystonia); gch1a; wu:fc16b10; zgc:195269