强直性肌营养不良症临床与病理学特点

Clinical and pathological features of myotonic dystrophy

目的探讨强直性肌营养不良症(DM)临床和病理学特点。方法回顾性分析25例DM患者的临床资料。结果 25例DM患者中男女发病比为1.27∶1,发病年龄集中10~40岁。慢性病程,中位病程为(8±12)年,有家族史者占45.83%。主要以四肢无力、双下肢无力、双手握拳后不能立即伸开和双上肢无力为首发症状,主要体征依次为肢体肌力下降、双手握拳后不能立即伸开、叩击性肌强直和肌肉萎缩。DM患者常合并其他多系统损害;多数患者血清CK轻至中度升高;EMG检查显示肌强直电位。DM的主要肌肉病理特征为肌纤维大小不一,核内移、核袋形成、肌膜核增多、肌源性群组化现象和主要累及Ⅰ型肌纤维的萎缩。DM患者肌肉病理免疫组织化学染色显示膜蛋白表达正常。其中8例患者经过知情同意后抽取外周血进行DMPK基因检测,结果显示均为DMPK基因突变,CTG重复次数均大于50,确诊为DM1型。结论 DM患者男性多见,多有遗传家族史。临床表现复杂多样,除肌强直、肌无力和肌萎缩最常见外,尚可伴其他多系统损害。EMG对该病的诊断较肌酶具有更大的价值。肌肉病理具有特异性的表现,免疫组化染色可作为鉴别诊断的依据,对本病的诊断价值不大。基因检测可确诊。

Objective To explore the clinical and pathological features of myotonic dystrophy（ DM）. Methods The clinical data of 25 DM patients were analyzed retrospectively. Results In the 25 DM cases,male and female incidence ratio was 1. 27∶ 1. The age of onset in DM was concentrating in the presence of 10-40 years old. DM was a chronic course with a median duration of（ 8 ± 12） years. There was accounting for 45. 83% in family history. The initial symptoms mainly manifested as limb weakness,lower extremity weakness,making a fist with both hands could not immediately stretch and upper limbs weakness. The order of the common signs was decline of limbs muscle strength,making a fist with both hands could not immediately stretch,percussion myotonia,muscle atrophy. DM patients in this group with other multisystem damage. Laboratory examination showed the majority of patients with mild to moderate elevations of serum creatine kinase. EMG showed myotonia potential in all DM patients. The main muscle pathology features of DM were different muscle fibers size,nuclear transfer,nuclear bag formation,increase in the muscle membrane nucleus,myogenic grouping phenomenon and major involvement of type Ⅰ muscle fiber atrophy. Immunohistochemical staining showed that membrane protein were normal. The group of 8 cases of patients after informed consent were extracted from the peripheral blood for DMPK gene detection. The results showed that 8 patients were DMPK gene mutation,in which CTG repeat number was greater than 50,diagnosed as type DM1.Conclusions DM onset is more common in men. A genetic family history is common for DM,whose clinical manifestations are complex and diverse,in addition to myotonia,muscle weakness and atrophy in the most common,which often associates with other multi-system damage. EMG is of more great value than CK in the diagnosis of DM.Muscle pathology is specific performance,immunohistochemical staining can be used as the basis for the differential diagnosis,but has little diagnostic value of this disease. Genetic testing can confirm the diagnosis for DM.