肢带型线粒体肌病一个家系的临床和病理特点研究

Clinical and pathological features of a family with limb-girdle type mitochondrial myopathy

目的研究肢带型线粒体肌病一个家系中患者的临床和骨骼肌病理特点。方法对一组以进行性肌肉无力为主要特点的家系中的3名患者进行临床资料收集及肌肉活检病理分析,对家系成员行线粒体基因检测。结果该家系患者发病年龄为30~47岁,主要表现为躯干肌及四肢近端肌无力和运动耐力下降,晚期出现呼吸肌受累。血肌酸激酶水平轻度升高,血乳酸升高,电生理检查结果示肌源性损害。骨骼肌病理检查显示3名患者均存在典型的破碎红纤维（RRF）,且患者病程越长（分别为2年、4年和14年）,肌无力严重程度越重,RRF数量越多（分别为5%、10%和30%）。细胞色素c氧化酶（COX）染色中RRF以深染为主,也可见阴性的RRF。琥珀酸脱氢酶（SDH）染色均未发现琥珀酸脱氢酶高反应性血管（SSVs）。基因检测发现该家系存在mt DNA A3243G突变。结论肢带型线粒体肌病患者选择性累及躯干和四肢近端肌群,骨骼肌中的RRF数量与患者病情进展程度呈正相关。

Objective To investigate the clinical and pathological features of skeletal muscles in patients with limb-girdle type mitochondrial myopathy in one family. Methods The clinical data of three patients within a family with progressive muscular weakness as the major feature were collected,and the results of muscle biopsy were analyzed. Mitochondrial gene detection was performed for all family members. Results In this family,the age of onset ranged from 30 to 47 years,and the major manifestations were muscle weakness and reduced exercise tolerance in trunk muscles and proximal extremities,as well as the involvement of respiratory muscles in the advanced stage. Laboratory examination revealed mildly elevated serum creatine kinase and increased blood lactic acid,and electrophysiological results showed myogenic damage. The pathological examination of skeletal muscles showed that all the three patients had typical ragged red fibers（ RRFs）; with the prolonged course of the disease（ 2,4,and 14 years,respectively）,muscle weakness became more severe and there were more RRFs（ 5%,10%,and 30%,respectively）. Cytochrome C oxidase staining showed that most RRFs were hyperchromatic,while there were negative RRFs. No strongly succinate dehydrogenase-reactive blood vessels were detected by succinodehydrogenase staining. Gene detection found the presence of mt DNA A3243 G mutation in this family. Conclusions In the patients with limb-girdle type mitochondrial myopathy,the muscle groups in the trunk and proximal extremities are involved selectively,and the number of RRFs in the skeletal muscles is positively correlated with the progression of the disease.