Rubio Juan C, Garcia-Consuegra Ines, Nogales-Gadea Gisela, Blazquez Alberto, Cabello Ana, Lucia Alejandro, Andreu Antoni L, Arenas Joaquin, Martin Miguel A
Centro de Investigación, Hospital Universitario 12 de Octubre, Madrid, Spain.
Hum Mutat. 2007 Feb;28(2):203-4. doi: 10.1002/humu.9474.
McArdle disease is a metabolic myopathy due to molecular defects in the myophosphorylase gene (PYGM), usually diagnosed in muscle biopsy. The aims of this study were to characterize genetically a large series of patients and to establish a protocol of molecular diagnosis on blood samples. We studied 55 Spanish unrelated patients with McArdle disease. Screening for the three more frequent mutations in the PYGM gene in the Spanish population (c.148C>T, p.R50X; c.613G>A, p.G205S; and c.2392T>C, p.W798R) were performed with polymerase chain-reaction and restriction fragment length polymorphism (PCR-RFLP) methods. To identify other mutant alleles, the coding region of PYGM gene was sequenced. The p.R50X mutation was observed in 38 patients, the p.G205S substitution in eight, and the p.W798R change in nine. Nine novel mutations, five missense (c.247A>T, p.I83F; c.521G>A, p.G174D; c.1094C>T, p.A365V; c.1468C>T, p.R490W; and c.1730A>G, p.Q577R), one nonsense mutation (c.2352C>A, p.C784X), three frameshift (c.402del, p.N134KfsX161; c.212_218dup, p.Q73HfsX7; c.1470dup, p.R491AfsX7), and nine previously reported mutations were found. In addition, we also updated the molecular data of 95 unrelated patients with McArdle disease studied thus far in our center. Of these patients, 56 were either homozygous or compound heterozygous for the p.R50X, p.G205S, or p.W798R mutation. By including in the molecular diagnosis protocol sequencing of the exons 1, 14, 17 and 18 of the PYGM gene, 16 further patients were characterized, and therefore we were able to detect the molecular defect in 72 out of 95 patients. A proposed molecular diagnosis protocol of the disease based on blood DNA would avoid muscle biopsy in 75.8% [95% confidence interval (95% CI): 62.1%-78.6%] of patients with McArdle disease.
麦卡德尔病是一种由于肌磷酸化酶基因（PYGM）分子缺陷导致的代谢性肌病，通常通过肌肉活检进行诊断。本研究的目的是对大量患者进行基因特征分析，并建立基于血液样本的分子诊断方案。我们研究了55名西班牙非亲属麦卡德尔病患者。采用聚合酶链反应和限制性片段长度多态性（PCR-RFLP）方法，对西班牙人群中PYGM基因三种最常见的突变（c.148C>T，p.R50X；c.613G>A，p.G205S；以及c.2392T>C，p.W798R）进行筛查。为了鉴定其他突变等位基因，对PYGM基因的编码区进行测序。在38名患者中观察到p.R50X突变，8名患者中观察到p.G205S替代，9名患者中观察到p.W798R改变。发现了9种新突变，5种错义突变（c.247A>T，p.I83F；c.521G>A，p.G174D；c.1094C>T，p.A365V；c.1468C>T，p.R490W；以及c.1730A>G，p.Q577R），1种无义突变（c.2352C>A，p.C784X），3种移码突变（c.402del，p.N134KfsX161；c.212_218dup，p.Q73HfsX7；c.1470dup，p.R491AfsX7），以及9种先前报道的突变。此外，我们还更新了本中心迄今为止研究的95名非亲属麦卡德尔病患者的分子数据。在这些患者中，56名患者为p.R50X、p.G205S或p.W798R突变的纯合子或复合杂合子。通过将PYGM基因第1、14、17和18外显子的测序纳入分子诊断方案，又鉴定出16名患者，因此我们能够在95名患者中的72名患者中检测到分子缺陷。基于血液DNA提出的该疾病分子诊断方案将使75.8%[95%置信区间（95%CI）：62.1%-78.6%]的麦卡德尔病患者无需进行肌肉活检。
