Section of Metabolic Diseases, Beatrix Children's Hospital, University Medical Centre of Groningen, University of Groningen, Groningen, The Netherlands.
Mol Genet Metab. 2011 Jan;102(1):13-7. doi: 10.1016/j.ymgme.2010.07.004. Epub 2010 Oct 27.
Homocysteine (Hcy) and in particular methylmalonic acid (MMA) are considered reliable parameters for vitamin B(12) status in healthy individuals. Phenylketonuria (PKU) patients are at risk for functional vitamin B(12) deficiency based on their diet.
The aim of this study was to investigate the prevalence of functional vitamin B(12) deficiency in continuously treated PKU patients and the association of parameters of vitamin B(12) and metabolic control.
In 75 continuously treated PKU patients of 1-37 years of age, serum vitamin B(12) concentrations, plasma Hcy, MMA, and phenylalanine concentrations were studied.
Eight patients had vitamin B(12) concentrations below normal. Out of these eight patients, two had elevated MMA and/or Hcy concentrations. Ten other patients with normal vitamin B(12) concentrations had elevated concentrations of MMA and/or Hcy.
A vitamin B(12) concentration within the reference range does not automatically imply a sufficient vitamin B(12) status. We recommend measuring serum MMA, or alternatively plasma Hcy, yearly in all PKU patients to diagnose functional vitamin B(12) deficiency.
本研究旨在调查持续性治疗的苯丙酮尿症（PKU）患者中功能性维生素 B12 缺乏症的患病率，并探讨维生素 B12 相关参数与代谢控制的关系。
对 75 例年龄 1-37 岁的持续性治疗的 PKU 患者进行血清维生素 B12 浓度、血浆同型半胱氨酸（Hcy）、甲基丙二酸（MMA）和苯丙氨酸浓度的研究。
8 例患者的维生素 B12 浓度低于正常值。这 8 例患者中，有 2 例 MMA 和/或 Hcy 浓度升高。另外 10 例维生素 B12 浓度正常的患者，MMA 和/或 Hcy 浓度升高。
维生素 B12 浓度在参考范围内并不自动意味着有足够的维生素 B12 状态。我们建议所有 PKU 患者每年测量血清 MMA，或替代地测量血浆 Hcy，以诊断功能性维生素 B12 缺乏症。
