Nonaka myopathy (MIM 605820) is caused by homozygous pathogenic variants in the GNE gene. It is a recessively inherited early adult-onset myopathy that usually preserves the quadriceps and presents with bilateral foot drop, usually caused by anterior tibialis weakness. In patients with Nonaka myopathy, serum creatine kinases are slightly elevated, muscle weakness progresses slowly, and ambulation loss develops after 15–20 yr. The current study aims to raise awareness of Nonaka myopathy that occurs as a rare phenotype due to pathogenic variants in GNE gene. Detailed family histories and clinical data were recorded. Whole exome sequencing was performed and co-segregation analysis of the family were done by Sanger sequencing. Also the homology model of the mutant protein was created with the ProMod3 algorithm. We identified a bialelic pathogenic variant (c.830G>A) in GNE gene, which explain the patients' clinical status. We present the main findings of two siblings with Nonaka myopathy together with detailed clinical and genetic profiles of the patients together with a three-dimensional mutant GNE protein model. We think that the clinical characteristics and the effect of the (c.830G>A) variant will facilitate our understanding of GNE gene in Nonaka myopathy pathogenesis.

野中肌病 (MIM 605820) 是由GNE基因纯合致病性变异引起的。它是一种隐性遗传的成人早期发病的肌病，通常保留股四头肌，并表现为双侧足下垂，通常由胫骨前肌无力引起。在野中肌病患者中，血清肌酸激酶轻微升高，肌肉无力进展缓慢，15-20 年后出现行走能力丧失。目前的研究旨在提高人们对野中肌病的认识，野中肌病是一种由GNE致病性变异引起的罕见表型基因。记录详细的家族史和临床数据。进行全外显子组测序，并通过桑格测序对该家族进行共分离分析。还使用ProMod3算法创建了突变蛋白的同源模型。我们在GNE基因中发现了一个双等位致病性变异 (c.830G>A) ，这解释了患者的临床状态。我们介绍了患有野中肌病的两个兄弟姐妹的主要发现，以及患者的详细临床和遗传特征以及三维突变 GNE 蛋白模型。我们认为(c.830G>A)变异的临床特征和作用将有助于我们了解GNE基因在野中肌病发病机制中的作用。