强直性肌营养不良症1型患者临床病理及基因诊断

Clinical and muscle biopsy pathological features and genetic testing in patients with myotonic dystrophy type 1

目的总结4例强直性肌营养不良症1型(DM1)患者临床、肌电图(EMG)、肌肉活检及基因诊断结果。方法对4例经临床、EMG诊断的DM患者进行肌肉活检、外周血DM1和DM2基因检测。结果 2例中年男患左尺侧腕屈肌活检呈现典型DM1肌肉病理特点:大量肌细胞核内移,Ⅰ型肌纤维萎缩,Ⅱ型肌纤维肥大。1例中年男患左腓肠肌活检示神经肌肉疾病晚期病理改变。基因检测结果均证实为DM1。1例青年女患右股外侧肌活检基本正常,第1次基因检测DM1和DM2基因正常,第2次和第3次基因检测证实为DM1。结论 DM1患者确诊需进行临床、EMG、肌肉病理、基因检测综合评价。由于取材部位选择不当或处于疾病晚期,肌肉活检不能提供典型证据。基因检测是诊断DM1的金标准,但有时会出现假阴性结果,因此,对于基因检测结果与临床诊断不符合的情况应注意复查。

Objective To summarize clinical,electromyography（ EMG）, muscle biopsy pathological features and ge- netic diagnosis of four cases of patients with myotonic dystrophy type 1 （ DM1 ）. Methods Four cases of patients were diag- nosed as myotonic dystrophy （DM） by clinical, electromyography diagnosis. They were operated on for muscle biopsy, and further carried out peripheral blood collection for DM1 and DM2 genetic testing. Results Left flexor carpi ulnaris biopsy showed typical DM1 muscle pathological features in two cases of middle-aged male patients ： variability in fiber size and cen- tralization of nuclei were found. A large number of muscle nuclei shift, type I muscle fiber atrophy, type ]I muscle fiber hy- pertrophy were detected. Late pathological changes of neuromuscular disease were found in a middle-aged male patient with his left gastrocnemius muscle biopsy. DM1 diagnosis were confirmed by their genetic testing results. A young female patient showed normal in right vastus lateralis muscle biopsy,her 1 st DM1 and DM2 genetic testing results were normal. DM1 was confirmed with 2nd and 3rd genetic testing. Conclusion Patients diagnosed as DM1 should based on the integrated results of manifestations, EMG, muscle biopsy and genetic testing. Due to inadequate parts or the late phase of the disease, muscle biopsy may not provide the typical muscle pathological evidence. Genetic testing is now considered the golden standard on diagnosis of DM1. Nevertheless ,there are sometimes false-negative results. So ,when the genetic testing result does not meet the clinical diagnosis,it should be tested again.