PDF(Pubmed)
Abstract：
Aromatic l-amino acid decarboxylase (AADC, EC 4.1.1.28) deficiency is a rare genetic disorder characterized by developmental delay, oculogyric crises, autonomic dysfunction and other problems, caused by biallelic mutations in the DDC gene leading to deficient activity of aromatic l-amino acid decarboxylase, an enzyme involved in the formation of important neurotransmitters, such as dopamine and serotonin. A clinical development program of gene therapy for AADC deficiency is ongoing. An important step for the success of this therapy is the early and precise identification of the affected individuals, but it has been estimated that around 90% of the cases remain undiagnosed. The availability measurement of the AADC activity is mandatory for an accurate biochemical diagnosis. Based on these statements, our objectives were to develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method suitable for the determination of the AADC activity, and to evaluate its capacity to confirm the deficiency of AADC in potential patients in Brazil. The AADC activities were measured in plasma samples of seven AADC deficient patients and 35 healthy controls, after enzymatic reaction and LC-MS/MS analysis of dopamine, the main reaction product. The results obtained showed clear discrimination between confirmed AADC deficient patients and healthy controls. The method presented here could be incorporated in the IEM laboratories for confirmation of the diagnosis of when a suspicion of AADC deficiency is present due to clinical signs and/or abnormal biomarkers, including when an increased level of 3-O-methyldopa (3-OMD) is found in dried blood spots (DBS) samples from high-risk patients or from newborn screening programs.
摘要：
芳香l-氨基酸脱羧酶(AADC，EC4.1.1.28）缺乏是一种罕见的遗传性疾病，其特征是发育迟缓，眼病危机，自主神经功能障碍和其他问题，由DDC基因的双等位基因突变引起，导致芳香族l-氨基酸脱羧酶的活性不足，一种参与重要神经递质形成的酶，如多巴胺和5-羟色胺。AADC缺乏的基因治疗的临床开发计划正在进行中。这种治疗成功的一个重要步骤是早期和精确地识别受影响的个体，但据估计，大约90%的病例仍未确诊。AADC活性的可用性测量对于准确的生化诊断是强制性的。基于这些陈述,我们的目标是开发一种适用于测定AADC活性的液相色谱串联质谱（LC-MS/MS）方法，并评估其在巴西潜在患者中确认AADC缺乏的能力。在7名AADC缺乏患者和35名健康对照的血浆样本中测量AADC活性，经过酶促反应和多巴胺的LC-MS/MS分析，主要反应产物。获得的结果显示在确认的AADC缺乏患者和健康对照之间有明显的区别。本文提出的方法可以纳入IEM实验室，以确认何时由于临床体征和/或异常生物标志物而存在AADC缺乏症的诊断。包括在高风险患者或新生儿筛查计划的干血斑（DBS）样本中发现3-O-甲基多巴（3-OMD）水平升高时。
