Table 1. Changes in CSF Neurotransmitter Metabolites and Pterins Concentrations in Disorders of Dopamine and Serotonin Metabolism (According to Refs (4)–⁶).

		pterins			neurotransmitter metabolites
enzymatic defect	Phea	BH4	BH2	NH2	HVA	HIAA	HVA/HIAA	3-OMD	5-HTrp	MHPG
GTPCH AR	↑	↓	N	↓	↓	↓	N	N	N	↓
PTPS	↑	↓	N	↑	↓	↓	N	N	N	↓
PCD	↑	↓	N	N	N	N	N	N	N	N
DHPR	↑	↓	↑	N	↓	↓	N	N	N	↓
GTPCH AD	N	↓	N	↓	↓	N or ↓	↓	N	N	↓
SR	N	↓	↑	N	↓	↓	N	N	N	↓
TH	N	N	N	N	↓	N	↓	N	N	↓
AADC	N	N	N	N	↓	↓	N	↑	↑	↓
DTDS	N	N	N	N	↑	N	↑	N	N	N

^aPhe (phenylalanine as determined in plasma), N (normal), GTPCH AR (GTP-cyclohydrolase deficiency autosomal recessive), PTPS (6-pyruvoyl-tetrahydropterin synthase deficiency), PCD (pterin-4α-carbinolamine dehydratase deficiency), DHPR (dihydropteridine reductase deficiency), GTPCH AD (GTP-cyclohydrolase deficiency autosomal dominant also known as Segawa syndrome or DOPA-responsive dystonia), SR (sepiapterin reductase deficiency), TH (tyrosine hydroxylase deficiency), AADC (aromatic l-amino acid decarboxylase deficiency), and DTDS (dopamine transporter deficiency syndrome).