强直性肌营养不良基因CTG数与心电图关系

Correlation between CTG trinucleotide repetition numbers of gene in myotonic dystrophy and electrocardiographic findings

目的 研究强直性肌营养不良 (简称DM )的肌张力蛋白激酶 (DMPK)基因中三核苷酸CTG(胞嘧啶、胸腺嘧啶、乌嘌啉 )重复数与DM病人心电图变化的关系。方法 经临床及用长模板扩增TMPCR法对 3个DM家系共 37个受检者进行检测 ,其中 2 5例确诊DM病人 ;1例可疑DM病人 ;余 11名家系成员属DM家系中正常人 ,在检测同时作心电图记录。结果 2 5例DM病人中心电图异常 2 0例 (80 % ) ,11名家系正常人中心电图异常 1例 (9% ) ,1例可疑DM病人的心电图正常 ,DM病人心电图异常率明显高于正常人 ,2 0例DM病人心电图异常主要表现为心脏传导障碍 ,而且心电图异常与DM基因CTG重复数有关 ,CTG数高者其心电图变化明显。结论 DM病人心脏受累明显增高 ,CTG重复数检测或许可提示心脏传导障碍的发生与程度。

Objective To study the relationship between CTG (cytosine, thymidine, guanine) repetition expansion of DMPK gene and cardiac involvement in patients with myotonic dystrophy. Method CTG repetition numbers of DMPK gene in 37 individuals of three pedigrees with DM were analyzed by using Long Expanded TM Template PCR system in 25 patients with DM, 11 normal individuals and a patient suspected to have DM were diagnosed according to results of clinical and molecular examinations. They received ECG test when their DNA were drawn from peripheral blood samples. Results ECG in 20/25 patients and 1/11 normal individuals were abnormal. ECG on a patient suspected to have DM was normal. The rate of electrocardiographic abnormalities was higher in patient group than that in normal group, ECG in patient group was mainly cardiac conduction abnormalities. The more CTG repetition numbers, the severer the cardiographic abnormalities. Conclusion The rate of cardiac involvment is higher in DM patients than that in normal individuals. Analysis of the numbers of CTG repeats may be an indication of onset of disease and the severity of cardiac involvement in DM patients. (Shanghai Med J, 2000,23∶659 662.)