苯丙酮尿症患儿中的糖巨肽：其苯丙氨酸含量会影响血液苯丙氨酸的控制吗？

Glycomacropeptide in children with phenylketonuria: does its phenylalanine content affect blood phenylalanine control?

作者信息

Daly A, Evans S, Chahal S, Santra S, MacDonald A

机构信息

Birmingham Children's Hospital, Dietetic Department, Birmingham, UK.

IMD (Inherited metabolic department) Birmingham Children's Hospital, Birmingham, UK.

出版信息

J Hum Nutr Diet. 2017 Aug;30(4):515-523. doi: 10.1111/jhn.12438. Epub 2017 Jan 22.

DOI:10.1111/jhn.12438

PMID:28111827

Abstract

BACKGROUND

In phenylketonuria (PKU), there are no data available for children with respect to evaluating casein glycomacropeptide (CGMP) as an alternative to phenylalanine-free protein substitutes [Phe-free L-amino acid (AA)]. CGMP contains a residual amount of phenylalanine, which may alter blood phenylalanine control.

METHODS

In a prospective 6-month pilot study, we investigated the effect on blood phenylalanine control of CGMP-amino acid (CGMP-AA) protein substitute in 22 PKU subjects (13 boys, nine girls), median age (range) 11 years (6-16 years). Twelve received CGMP-AA and nine received Phe-free L-AA, (1 CGMP-AA withdrawal). Subjects partially or wholly replaced Phe-free L-AA with CGMP-AA. If blood phenylalanine exceeded the target range, the CGMP-AA dose was reduced and replaced with Phe-free L-amino acids. The control group remained on Phe-free L-AAs. Phenylalanine, tyrosine and Phe : Tyr ratio concentrations were compared with the results for the previous year.

RESULTS

In the CGMP-AA group, there was a significant increase in blood phenylalanine concentrations (pre-study, 275 μmol L ; CGMP-AA, 317 μmol L ; P = 0.02), a decrease in tyrosine concentrations (pre-study, 50 μmol L ; CGMP-AA, 40 μmol L ; P = 0.03) and an increase in Phe : Tyr ratios (pre-study, Phe : Tyr 4.9:1; CGMP-AA, Phe : Tyr 8:1; P = 0.02). In the control group there was a non-significant fall in phenylalanine concentrations (pre-study 325μmol/L: study 280μmol/L [p = 0.9], and no significant changes for tyrosine or phe/tyr ratios [p = 0.9]. Children taking the CGMP-AA found it more acceptable to L-AA.

CONCLUSIONS

Blood phenylalanine control declined with CGMP-AA but, by titrating the dose of CGMP-AA, blood phenylalanine control remained within target range. The additional intake of phenylalanine may have contributed to the change in blood phenylalanine concentration. CGMP-AA use requires careful monitoring in children.

摘要

背景

在苯丙酮尿症（PKU）中，关于评估酪蛋白糖巨肽（CGMP）作为无苯丙氨酸蛋白质替代物[无苯丙氨酸L-氨基酸（AA）]的替代品，尚无针对儿童的数据。CGMP含有残留量的苯丙氨酸，这可能会改变血液中苯丙氨酸的控制水平。

方法

在一项为期6个月的前瞻性试点研究中，我们调查了CGMP-氨基酸（CGMP-AA）蛋白质替代物对22名PKU受试者（13名男孩，9名女孩）血液苯丙氨酸控制的影响，中位年龄（范围）为11岁（6 - 16岁）。12名受试者接受CGMP-AA，9名接受无苯丙氨酸L-AA（1名退出CGMP-AA组）。受试者用CGMP-AA部分或全部替代无苯丙氨酸L-AA。如果血液苯丙氨酸超过目标范围，则降低CGMP-AA剂量并用无苯丙氨酸L-氨基酸替代。对照组继续使用无苯丙氨酸L-AA。将苯丙氨酸、酪氨酸和苯丙氨酸：酪氨酸比值浓度与上一年的结果进行比较。

结果

在CGMP-AA组中，血液苯丙氨酸浓度显著升高（研究前为275μmol/L；CGMP-AA组为317μmol/L；P = 0.02），酪氨酸浓度降低（研究前为50μmol/L；CGMP-AA组为40μmol/L；P = 0.03），苯丙氨酸：酪氨酸比值升高（研究前苯丙氨酸：酪氨酸为4.9:1；CGMP-AA组为8:1；P = 0.02）。在对照组中，苯丙氨酸浓度有不显著的下降（研究前325μmol/L：研究时280μmol/L [p = 0.9]），酪氨酸或苯丙氨酸/酪氨酸比值无显著变化[p = 0.9]。服用CGMP-AA的儿童发现它比L-AA更容易接受。