四氢生物喋呤负荷试验在高苯丙氨酸血症鉴别诊断中的临床应用

目的探讨四氢生物喋呤（BH4）负荷试验在高苯丙氨酸血症（HPA）鉴别诊断中的应用价值。方法自2008年1月-2010年6月,27例HPA患儿采用口服BH4（20 mg/kg）负荷试验。对其中血苯丙氨酸（Phe）浓度小于6 mg/dl患儿采用口服Phe-BH4联合负荷试验,结合尿喋呤分析、血红细胞二氢喋呤还原酶（DHPR）活性测定。结果 （1）在BH4负荷试验中,不同类型HPA患儿的血Phe浓度表现出各不相同的改变。27例HPA患儿中,共鉴别出5例BH4缺乏症,9例BH4反应性苯丙氨酸羟化酶（PAH）缺乏症,13例BH4无反应性苯丙氨酸羟化酶（PAH）缺乏症。（2）在22例中度苯丙酮尿症（PKU）患儿中,9例为BH4反应性PAH缺乏症。结论 BH4负荷试验在HPA早期鉴别诊断中十分重要,部分中度PKU对BH4有反应,可使用BH4替代治疗。

Clinical Application of Tetrahydrobiopterin Loading Test in Differential Diagnosis of Hyperphenylalaninemia

Objective To explore the application value of tetrahydrobiopterin(BH4) loading test in differential diagnosis of hyperphenylalaninemia(HPA).Methods From January,2008 to June,2010,BH4(20 mg/kg) loading test was carried out in 27 patients with HPA,and phenylalanine(Phe,100 mg/kg) combined with BH4 loading test were performed in the patients whose basic phenylalanine blood concentrations were less than 6 mg/dl.The urinary pterine profile analysis and dihydropteridine reductase(DHPR) activity in dry blood filter spot were analyzed simultaneously.Results The characteristic curves of the blood levels were observed in 27 patients after BH4 loading test.Among them,5 patients were diagnosed as BH4 deficiency,9 patients as BH4 responsive PAH deficiency.9 of 22 moderate PKU patients were diagnosed as BH4 responsive PAH deficiency.Conclusions BH4 loading test plays an important role in early differential diagnosis of HPA patients.Some patients with moderate PKU are responsive to BH4 and can be treated with BH4.