Nonaka肌病临床病理及肌肉磁共振特点分析

目的探讨Nonaka肌病的临床、肌肉病理及肌肉磁共振特点。方法入选2例患者,女性1例,男性1例,临床表现均以双下肢远端肌肉无力、萎缩为主,双上肢仅轻度受累。血清肌酸激酶轻度升高,肌电图提示肌源性损害,神经传导速度均正常。对患者完善大腿及小腿肌肉磁共振检查,并予以左上肢肱二头肌活检,进行组织学、酶组织化学及免疫组织化学染色,抽取外周静脉血2mL送基因公司进行遗传性肌肉病相关基因测序。结果肌肉病理提示,肌纤维肥大、萎缩、再生,肌纤维内可见镶边空泡,符合肌病样病理改变。肌肉MRI提示,大腿股四头肌脂肪化程度较轻,尤其是股外侧肌未受累及,大腿后组肌群及小腿胫前肌、胫后肌脂肪化程度严重。基因结果均提示GNE基因突变。结论 Nonaka肌病是一种与GNE基因突变相关的常染色体隐性遗传性远端肌病,临床表现特点为胫前肌首先受累,而股四头肌早期不受累。病理改变特点为肌纤维内镶边空泡形成。肌肉MRI可提示肌肉脂肪化的程度及分布规律,为诊断提供依据。

The clinicopathological characteristics and muscle MRI features of Nonaka myopathy

Objective To investigate the characteristics of both clinical pathology and muscle MRI in Nonaka myopathy.Methods The two included patients(one male and one female)who mainly represented weakness and atrophy in both lower limbs as well as slight abnormality in both upper limbs showed mild increase in creatine kinase(CK)level as well as myogenic abnormality and normal nerve conduction velocity observed in electromyogram(EMG).All patients received MRI in order to examine calf and thigh muscles and we used histological,enzyme-histochemical and immunohistochemical techniques to detect bicipital muscle of arm.Finally,peripheral venous blood of 2 mL was extracted to sequence related gene of hereditary muscular disorders,which was carried out by gene company.Results Muscle fibers presented by muscle biopsy showed atrophy,hypertrophy and regeneration and the presence of rimmed vacuoles(RV),which conformed to pathological changes of myopathy.Muscle MRI pointed out mild fatty infiltration in quadriceps,no affected changes in vastus lateralis muscle and severe fatty infiltration in posterior group of thigh muscles.The genetic analysis showed mutation of GNE gene.Conclusion Nonaka myopathy is a GNE gene-induced disease and inherited in an autosomal recessive manner,characterized by tibialis anterior muscles being affected initially and quadriceps being not affected at early stage.Typical muscle pathology shows the formation of rimmed vacuoles and the muscle MRI directly displays the degree and the distribution of muscle fatty infiltration.