CLINICAL CHARACTERISTICS: PTS-related tetrahydrobiopterin deficiency (PTPSD) results in a lack of tetrahydropterin, an important cofactor for phenylalanine hydroxylase (PAH), tyrosine hydroxylase, and tryptophan hydroxylase. Deficiency can thus lead to neurotransmitter and neuropsychiatric disorders. The clinical spectrum of PTPSD is broad and differs according to age of onset, severity of disease, and whether preventative therapies were initiated and maintained from an early age. In the severe…
