Table 1.

Nomenclature for BH4 disorders

Disease name	Gene symbol	Inheritance	Affected enzyme	OMIM	Gene locus
GTP cyclohydrolase 1 deficiency	GCH1	AD	GTPCH1	128,230	14q22.2
GTP cyclohydrolase 1 deficiency	GCH1	AR	GTPCH1	233,910	14q22.2
6-pyruvoyl-tetrahydropterin synthase deficiency	PTS	AR	PTPS	261,640	11q23.1
Sepiapterin reductase deficiency	SPR	AR	SR	612,716	2p13.2
Q-dihydropteridine reductase deficiency	QDPR	AR	DHPR	261,630	4p15.32
Pterin-4-alpha-carbinolamine dehydratase deficiency	PCBD1	AR	PCD	264,070	10q22.1

AD Autosomal dominant, AR Autosomal recessive, BH4 Tetrahydrobiopterin, GTP Guanine triphosphate