[Screening for 6-pyruvoyl-tetrahydrobiopterin synthase (PTPS) deficiency: clinical analysis of 9 patients with PTPS deficiency].

OBJECTIVE: To show the incidence of 6-Pyruvoyl-tetrahydrobiopterin synthase (PTPS) deficiency among hyperphenylalaninemia and conclude the clinical outcome of patients with PTPS deficiency. METHODS: The urinary neopterin (N) and biopterin (B) were determined by HPLC in 69 PKU cases. BH(4) loading test and mutation analysis of PTPS were performed in patients who had abnormal urinary pterin patterns. Three patients with PTPS deficiency were placed on treatment with combined synthetic BH(4) and neurotransmitter precursors such as Dopa and 5-hydroxytryptophan. RESULTS: 9 out of 69 patients, whose urinary N/B exceed 38 [normal: 1.17 (1.4)] and B% were less than 5% [normal: 55.9 (18.6)], were diagnosed as having PTPS deficiency. Four kinds of PTPS gene mutations (P87S, N52S, D96N and G144R) were detected from 4 out of 9 cases with PTPS deficiency. The last mutation was a new mutation. The three typical PTPS-deficient patients had satisfactory physical development, their intelligence quotient (IQ) were 70 approximately 80 after treatment and one partial PTPSD had normal growth and mental development. CONCLUSION: The screening for BH(4) deficiency should be carried out among all patients with hyperphenylalaninemia in order to avoid misdiagnosis.