强直性肌营养不良的临床与肌肉病理研究

A clinical and pathological study of 3 cases of myotonic dystrophy

目的 研究强直性肌营养不良 (DM)的临床与病理变化。方法 总结 3例 DM的临床特点 ,并对肌活检标本进行光镜和电镜检查。结果 3例 DM患者 ,年龄 2 5～ 40岁。临床特点为缓慢进行的四肢无力 ,肌强直发作。腱反射迟钝对称。前额秃发。EMG示肌源性损害 ,可见肌强直发放。肌活检光镜下可见肌纤维萎缩 ,肌核内移呈核链形成 ,肌纤维横纹尚存 ,晚期可见脂肪细胞浸润 ;电镜下可见肌纤维变性、溶解 ,Z带破坏 ,线粒体肿胀、变性。结论 DM的肌肉病理与临床表现相关 ,临床表现愈重 ,肌肉损害愈明显。近年来认为 DM是 DMPK基因 3,非翻译区 CTG三核苷酸异常重复扩增所致。

Objective The aim of the study was to investigate the clinical and pathological features of myotonic dystrophy (DM). Method Muscle biopsied specimens from 3 DM patients who were two females and one male and aged from 29 to 40 years had an onset with limb weakness and worsen progressively. Myotonia was commonly seen. Deep reflexes were bilaterally blunt. Frontal balding were all seen in the patients. Their muscular lesions and myotonia were confirmed by EMG.Light microscopic examination showed atropic fibers,inward migration of nuclei,increased numbers of nuclei which tended to form rows.Severe fatty infiltration was seen at advanced stage.Ultrastructural studies showed degeneration and lysis of myofilaments,degenerational and swollen mitochondria,distortion of Z bands.Conclusion The pathological changes in DM patients were correlated with their clinical manifestations,that was to say,the more severe clinical manifestations the DM patients had,the more severe muscular lesions they had as well.It was found in recent years that DM was associated with increasing CTG repeats in the 3 , untranslated region of the myotonin protein kinase gene (DMPK) located on chromosome 19 q13.3.