Congenital myopathies are a heterogeneous group of conditions diagnosed based on the clinical presentation, muscle histopathology and genetic defects. Recessive mutations in the SPEG gene have been described in recent years and are primarily associated with centronuclear myopathy with cardiomyopathy. In this report, we describe two Brazilian siblings, aged 13 and 6 years, with a novel homozygous mutation (c.8872 C>T:p.Arg2958Ter) in the SPEG gene leading to a congenital myopathy. In the older sibling, the muscle biopsy showed fiber size disproportion. The mean diameter of type 2 fibers (119 µm) was significantly higher than type 1 (57 µm) (P < 0,001) with a 72% prevalence of type 1 fibers. The patient also had progressive cardiomyopathy treated with heart transplantation. The present report expands the muscle histopathological findings related to mutations in the SPEG gene, including fiber size disproportion without central nuclei. Additionally, this report describes the first case of heart transplantation in a patient with SPEG mutations.

先天性肌病是根据临床表现、肌肉组织病理学和遗传缺陷诊断出的一组异质性疾病。近年来已经描述了 SPEG 基因的隐性突变，并且主要与伴有心肌病的中央核肌病有关。在本报告中，我们描述了两个年龄分别为 13 岁和 6 岁的巴西兄弟姐妹，他们在 SPEG 基因中具有新的纯合突变 (c.8872 C > T : p.Arg2958Ter)，导致先天性肌病。在年长的兄弟姐妹中，肌肉活检显示纤维大小不均衡。2 型纤维的平均直径 (119 µm) 明显高于 1 型 (57 µm) ( P< 0,001)，1 型纤维的患病率为 72%。该患者还患有进行性心肌病，接受了心脏移植治疗。本报告扩展了与SPEG基因突变相关的肌肉组织病理学发现，包括没有中央核的纤维大小不均衡。此外，本报告描述了第一例 SPEG 突变患者的心脏移植病例。