Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
Neuromuscul Disord. 2010 Apr;20(4):238-40. doi: 10.1016/j.nmd.2010.01.011. Epub 2010 Mar 19.
Cap myopathy is a congenital myopathy with cap-like structures under the sarcolemma. Mutations in TPM2 and TPM3 genes have been reported in cap myopathy so far. We report a newborn boy with persistent profound weakness who required gastro-jejunal tube feeding, tracheostomy and life-long ventilation until he died at 5 years of age. Muscle biopsy at 5 weeks of age was uninformative. Repeat biopsy at 4.5 years revealed subsarcolemmally located caps that were immunopositive for alpha-actinin, actin and to some extent, desmin. EM confirmed loosely arranged thin filaments and paucity of thick filaments. Molecular analysis of ACTA1 gene identified a novel de novo Met49Val [corrected] mutation. In addition to a new ACTA1 gene mutation, our case emphasizes the genetic heterogeneity of cap myopathy and its association with ACTA1 gene as well as the importance of repeat muscle biopsy in patients with undiagnosed muscle weakness.
肌帽病是一种先天性肌病，在肌膜下有帽状结构。到目前为止，已经在肌帽病中发现了 TPM2 和 TPM3 基因突变。我们报告了一例新生儿男孩，他持续存在严重的无力，需要胃空肠管喂养、气管切开和终身通气，直到他在 5 岁时死亡。5 周龄时的肌肉活检没有提供信息。4.5 岁时的重复活检显示，位于肌膜下的帽状结构免疫阳性，α-肌动蛋白、肌动蛋白和在一定程度上，结蛋白。EM 证实了松散排列的细肌丝和稀少的粗肌丝。ACTA1 基因突变的分子分析确定了一个新的从头 Met49Val [更正]突变。除了新的 ACTA1 基因突变外，我们的病例还强调了肌帽病的遗传异质性及其与 ACTA1 基因的关联，以及在未明确诊断的肌肉无力患者中重复进行肌肉活检的重要性。
