Department for Women and Child Health, Hospital for Children and Adolescents, University Hospitals, University of Leipzig, Leipzig, Germany.
Department of Neurology, Martin-Luther-University Halle-Wittenberg, Halle-Wittenberg, Halle, Germany.
Neuropediatrics. 2020 Feb;51(1):53-56. doi: 10.1055/s-0039-1694977. Epub 2019 Sep 21.
Metabolic myopathies are heterogeneous hereditary diseases affecting skeletal muscle energy supply. Symptoms usually comprise pain, cramps, hypotonia, weakness, and myoglobinuria.We present a boy with recurrent myalgia and weakness after some minutes of exercise or during febrile infections since early infancy. First laboratory workup at the age of 9 years showed no abnormalities, apart from a slightly elevated creatine kinase. After exclusion of common structural and metabolic myopathies, next generation sequencing panel (4 years after the initial diagnostic metabolic workup) revealed two potentially pathogenic missense mutations in the gene (c.149C > A (p.P50H) and c.1459G > A (p.E487K)).Our case underscores the clinical variability of muscle carnitine palmitoyltransferase II (CPT II) deficiency and illustrates a pitfall of diagnostic algorithms for metabolic myopathies. Myalgia following exercise of a few minutes duration would have argued for a carbohydrate and against a fatty acid metabolic defect. However, CPT II deficiency is the most common disorder of muscle fatty acid metabolism and should be considered even in atypical scenarios. Analyses of plasma acyl carnitine profile during acute metabolic crises may help to unmask biochemical markers which are often overlooked in dried-blood analyses.
代谢性肌病是一组影响骨骼肌能量供应的异质性遗传性疾病。其症状通常包括疼痛、痉挛、低张力、无力和肌红蛋白尿。我们报告了一名男孩，从婴儿期开始，在运动几分钟后或发热性感染期间反复出现肌痛和无力。9 岁时首次进行实验室检查，除肌酸激酶略有升高外，无其他异常。在排除常见的结构性和代谢性肌病后，下一代测序小组（在最初的代谢性诊断工作后 4 年）发现 基因中有两个潜在致病性错义突变（c.149C>T（p.P50H）和 c.1459G>A（p.E487K））。我们的病例强调了肉碱棕榈酰转移酶 II（CPT II）缺乏症的临床表现变异性，并说明了代谢性肌病诊断算法的一个缺陷。持续几分钟的运动后出现肌痛会支持碳水化合物代谢缺陷，而不是脂肪酸代谢缺陷。然而，CPT II 缺乏症是最常见的肌肉脂肪酸代谢紊乱，即使在非典型情况下也应考虑到这种疾病。在急性代谢危机期间分析血浆酰基肉碱谱可能有助于揭示在干血分析中经常被忽视的生化标志物。
