目的:分析强直性肌营养不良症(myotonic dystrophy or dystrophia myotonia,DM)的临床、家系和遗传特征,提高对强直性肌营养不良症的认识,为DM的基因诊断和产前诊断提供分子依据.方法:收集2个DM家系,对其临床进行详细分析,用片段分析法对2个DM家系内的4例患者和1个家系成员DM1致病基因强直性肌营养不良蛋白激酶(myotonic dystrophy protein kinase,DMPK)基因的3′端非翻译区CTG三核苷酸重复次数进行检测.结果:在2个DM家系中发现有1例亚临床症状患者,另5例临床患者均为慢性起病,以肌强直、肌无力和肌萎缩为主要表现,1例有斧状脸,1例合并白内障和糖尿病,3例合并有秃头,3例患者肌电图检查有肌强直放电和肌源性损害.4例患者的DMPK基因的3′端非翻译区CTG三核苷酸重复次数均>50次.结论:强直性肌营养不良症具有遗传早现现象,基因分析可以确诊本病和明确亚临床患者,借遗传咨询和产前诊断可以避免此类患者的出生.%Objective To analyze the clinical, familial and hereditary features of myotonic dystrophy to improve the knowledge and provide molecule evidence for gene diagnosis and prenatal diagnosis of myotonic dystrophy or dystrophia myotonia (DM) families. Methods Clinical data of 2 DM families were collected based on the probands. The number of trinucleotide CTG repeat in the 3' untranslated region of myotonic dystrophy protein kinase (DMPK) gene on chromosome 19 was determined by DNA sequence and repeat fragment. Results Except for 1 subclinical patient, another 5 patients progressed slowly with the features of myotonic muscular weakness and atrophy. One patient had hatchet face, 1 had cataract and diabetes mellitus, and the other 3 were bald. Electromyologram showed 3 patients had myotonic discharge and myopathic abnormalities. The number of trinucleotide CTG repeat in the 3＇ untranslated region of DMPK gene of 5 patients exceeded 50.Conclusion DM can be anticipated. Gene analysis can verify the disease and identify subclinical patients. It helps to prevent the DM births by hereditary consultation performing prenatal diagnosis.
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