高苯丙氨酸血症患儿尿中代谢物水平分析

Analysis of urine metabolites levels in children with hyperphenylalaninemia

目的通过检测高苯丙氨酸血症（HPA）患儿血苯丙氨酸（Phe）及尿苯丙酮酸、苯乙酸及苯乳酸水平，探讨其血Phe水平与尿代谢产物的关系。方法研究对象为55例HPA患儿，其中20例为轻度HPA（血Phe浓度〈360mmol／L）、35例为苯丙酮尿症（PKU，血Phe浓度360M200mmol／L）；血r,he水平检测采用串联质谱干血滤纸片法；尿苯丙酮酸、苯乙酸及苯乳酸水平检测采用尿素酶预处理气相色谱-质谱法。结果HPA患儿血Phe水平与尿苯丙酮酸、苯乙酸及苯乳酸水平呈正相关（r=0．61～0．84，P均〈0．01）。轻度HPA与PKL噫儿尿苯丙酮酸、苯乙酸及苯乳酸水平差异有统计学意义（P均〈0．01）；70％轻度HPA患儿及5．71％PKU患儿的尿苯丙酮酸、苯乙酸及苯乳酸水平正常。结论HPA患儿尿中苯丙酮酸、苯乙酸及苯乳酸水平的变化与血Phe浓度密切相关，单纯检测尿苯丙酮酸、苯乙酸及苯乳酸可能导致假阴性。

Objective To explore the relationship between blood phenylalanine （Phe） and urine metabolites by detection of blood Phe, urinary phenylpyruvate, phenyiacetate and phenyllactate levels in children with hyperphenylalaninemia （HPA） Methods Fifty-five children with hyperphenylalaninemia were selected, the level of Phe in the dried blood spot was tested by tandem mass spectrometry and urine levels of phenylpyruvate, phenylacetate and phenyllactate pretreated using urease were tested by gas chromatography mass spectrometry. Results Blood level of Phe and urine levels of phenylpyruvate, phenylac- etate and phenyllactate showed significant positive correlations （r=0.61-0.84, P〈0.01）. For both blood level of Phe 360 mmol/ L and 360-1 200 mmol/L groups, rank tests showed significant differences among urine phenylpyruvate, phenylacetate and phenyllactate （P〈0.01）; The normal number of children with urine levels of phenylpyruvate, phenylacetate and phenyllactate showed 14 cases （70%）, 2 cases （5.71%）, both was significantly different （P〈0.01）. Conclusions The variation of urinary phe- nylpyruvate, phenylacetate and phenyllactate is correlated to blood Phe in children with HPA. However, it will lead to false negative result if the diagnosis made by detecting phenylpyruvate, phenylacetate and phenyllactate only.