不典型的远端肌病(calpainopathy)1例研究

Atypical Distal Myopathy:A Case with Calpainopathy

目的:分析1例表现为"远端肌无力"的calpainopathy患者的临床、影像学及病理学特点,并与其他远端肌病相鉴别。方法:以"双下肢远端肌无力"起病的患者1例,完善体格检查、血生化、肌电图和肌肉MR检查。肌肉活检后应用免疫组化染色法观察肌细胞各种胞膜蛋白表达情况,采用免疫印迹法半定量法分析dysferlin蛋白及calpain-3蛋白水平。结果:肌肉MRI示患者以臀中肌、臀小肌、大腿后群及小腿内侧群肌肉受累为著,肌肉病理提示"肌病样"改变,组化染色未发现胞质内存在镶边空泡,免疫组化染色提示dysferlin蛋白无缺失。最终经免疫印迹检测发现该患者肌肉组织calpain-3 94 000/60 000谱带完全缺失,诊断为calpainopathy。结论:远端肌病包含疾病种类繁多,calpainopathy亦可为其中之一。肌肉影像学可为其鉴别提供一定的线索,确诊需依赖免疫印迹检测。

Aim： A case with calpainopathy presenting distal muscular weakness was reported and his clinical characters and pathological features were analyzed so as to differentiate with other distal myopathies. Methods： One patient admitted to our hospital with distal muscular weakness in lower limbs was selected to perform physical examination, EMG study and muscle MRI. After muscle biopsy, immunohistochemical staining for the major sarcolemma proteins was performed. Subsequently, Western blot was employed to analyze dysferlin and calpain- 3 proteins semi-quantitatively. Results： Muscle MRI revealed that glutaeus medius, glutaeus minimus, posterior compartment of thives and medial part of calves were severely involved. Histochemical staining demonstrated the absence of rimmed vacuoles while immunohistochemical staining of dysferlin was positive for the case. Western blot analysis revealed that calpain-3 94 000 and 60 000 bands were both negative. Conclusion： Distal myopathy is a clinical syndrome characterized by progressive distal muscular weakness, which encompasses diversified distal myopathies including calpainopathy. Muscle MRI can be a little help. Yet Western blot analysis of calpain-3 is a crucial implement in making a differential diagnosis.