Reardon W, Harley H G, Brook J D, Rundle S A, Crow S, Harper P S, Shaw D J
Institute of Medical Genetics, University of Wales College of Medicine, Heath Park, Cardiff.
J Med Genet. 1992 Nov;29(11):770-3. doi: 10.1136/jmg.29.11.770.
A clinical and molecular study is reported of 83 patients considered to be minimally affected with myotonic dystrophy (DM). These had been identified in three ways: 60 subjects were identified on clinical grounds and were divided into those with and those without neuromuscular involvement (groups I and II); nine subjects were at high risk of carrying the DM gene but had a normal phenotype (group III); and 14 were parents of definitely affected patients where neither parent showed clinical abnormalities (group IV). PCR analysis of the CTG repeat in the DM gene showed a range of 70 to 230 repeats for the younger at risk patients in group III, while the asymptomatic gene carriers in group IV had 53 to 60 repeats. The sensitivity of diagnosis by EMG was found to be 39%. For ophthalmic signs this was 97.5%. This suggests that assignment on the basis of minimal clinical features carries a significant error. Molecular analysis, in conjunction with established clinical investigations, should prove valuable in the identification and exclusion of minimal myotonic dystrophy.
本文报道了一项针对83例被认为患有轻度强直性肌营养不良（DM）患者的临床与分子研究。这些患者通过三种方式被确定：60例患者基于临床症状被确定，并分为有和没有神经肌肉受累的两组（I组和II组）；9例患者携带DM基因的风险很高，但表型正常（III组）；14例是明确患病患者的父母，而父母双方均未表现出临床异常（IV组）。对DM基因中CTG重复序列的PCR分析显示，III组中处于风险中的年轻患者的重复序列范围为70至230次，而IV组中的无症状基因携带者有53至60次重复。通过肌电图诊断的敏感性为39%。对于眼部体征，这一敏感性为97.5%。这表明基于最小临床特征进行诊断存在重大误差。分子分析与既定的临床研究相结合，在识别和排除轻度强直性肌营养不良方面应具有重要价值。
