儿童型杆状体肌病2例临床、病理和基因研究

Clinical, pathological and genetic studies of two cases of childhood-onset nemaline myopathy

摘要:

本文报道经肌肉病理及基因诊断确诊的儿童型杆状体肌病2例。2例患者均幼儿期起病，以肌肉无力为首发表现，病程长，进展缓慢。2例患者的肌肉病理光镜均发现Gomori染色及HE染色肌纤维胞浆内尤其肌膜下杆状物质沉积；电镜检查可见致密杆状体位于肌纤维肌膜下，与肌纤维长轴平行，部分肌纤维肌丝灶性溶解、坏死；基因检测发现两患儿分别存在杆状体肌病两种最常见的基因突变：ACTA1基因杂合突变（c.1013A > C）和NEB基因复合杂合突变（c.18676C > T及c.9812C > A）。杆状体肌病是一种常色体显性或隐性遗传的少见肌病，肌细胞胞浆中的杆状体是特征性肌肉病理改变。病理诊断和基因诊断是诊断杆状体肌病的金标准。

Abstract:

This article reports two cases of childhood-onset nemaline myopathy diagnosed by muscle pathology and genetic diagnosis. The two patients had onset in early childhood, with muscle weakness as the first manifestation, as well as long disease duration and slow progression. Gomori staining and hematoxylin-eosin staining showed redstained rods in the sarcoplasmic cytoplasm and sarcolemma under a light microscope. Electron microscopy showed that the dense nemaline rods were located under the muscle fiber sarcolemma and parallel to the long axis of the muscle fibers, and some muscle fiber myofilaments were dissolved and necrotic. Gene testing found that one of the two patients had heterozygous mutation (c.1013A > C) in the ACTA1 gene, and the other had compound heterozygous mutation (c.18676C > T and c.9812C > A) in the NEB gene. The two mutations were more common in nemaline myopathy. Nemaline myopathy is a recessive or dominant inheritance myopathy, in which the nemaline rod in the cytoplasm of myocytes is a characteristic muscle pathological change. Pathological and genetic diagnosis is the gold standard for diagnosis of nemaline myopathy.