目的分析和总结强直性肌营养不良1型(myotonic dystrophy type 1,DM1)患者的临床特点,以提高对该病复杂临床表现的认识水平。方法选取2009-2012年在作者医院收治并经分子诊断确诊为DM1的患者45例,回顾性分析其临床资料。结果 45例中27例有阳性家族史。首发症状以握拳后放松困难最常见(24/45)。肌强直、肌无力、肌萎缩的发生率分别为95.56%、93.33%、75.56%,主要以头面诸肌、颈肌、肢体远端受累明显。除骨骼肌外,DM1还可累及眼睛(晶状体)、心脏(主要为传导系统)、中枢神经系统、颅骨、内分泌、呼吸系统等,临床表现多样。结论典型的DM1为青中年隐袭起病,阳性家族史有助于诊断。肌强直以舌肌和大鱼际最敏感,叩击这两个部位有助于不典型肌强直症状的检出。骨骼肌以外,白内障发生率最高,对本病有一定的提示作用。男性早秃和斧头脸为本病突出的面部特征。对于怀疑DM1的患者,应及早开展遗传咨询。对于诊断DM1的患者,应全面评估并尽早处理多系统损害(尤其对于心脏和呼吸系统),同时进行定期随访复查。
强直性肌营养不良（myotonic dystrophy,DM）是一种起病隐匿、进展缓慢的常染色体显性遗传病,临床异质性高,以肌强直、肌无力、肌萎缩为主要特点,常伴有心律失常、认知功能障碍、晶状体浑浊、胰岛素抵抗、性腺功能紊乱等多系统损害。DM是最常见的成人型肌营养不良,分为DM1和DM2两型,其中DM1约占98%,致病基因位于19q13.3,由强直性肌营养不良蛋白激酶（dystrophia myotonica protein kinase,DMPK）基因3’非翻译区不稳定CTG三核苷酸重复序列异常扩增引起；DM2的致病基因位于3q21．3.
Background Myotonic dystrophy type 1(DM1) is an autosomal dominant multisystem disease caused by abnormal expansion of cytosine-thymine-guanine(CTG) repeats in the myotonic dystrophy protein kinase gene. The clinical manifestations of DM1 are multisystemic and highly variable, and the unstable nature of CTG expansion causes wide genotypic and phenotypic presentations, which make molecular methods essential for the diagnosis. So far, very few studies about molecular diagnosis in Chinese patients with DM1 have been reported. Therefore, we carried out a study using two different methods in molecular diagnosis to verify the validity in detecting CTG expansion in Chinese patients showing DM signs.Methods A total of 97 Chinese individuals were referred for molecular diagnosis of DM1 using conventional polymerase chain reaction(PCR) accompanied by Southern blotting and triplet primed PCR(TP-PCR). We evaluated the sensitivity and limitation of each method using percentage.Results By conventional PCR 65 samples showed only one fragment corresponding to the normal allele and 62 out of them were correctly diagnosed as DM1 by TP-PCR and three homologous non-DM1 samples were ruled out; Southern blotting analysis successfully made 13 out of 16 correct diagnoses with a more sensitivity using α-32P-labeled probes than dig-labeled probes.Conclusion Molecular analysis is necessary for the diagnosis of DM1 and TP-PCR is a reliable, sensitive, and easily performed method in molecular diagnosis which is worthy to be popularized.
