上海松江一个强直性肌营养不良家系DNA检测

目的 分析上海松江区一个强直性肌营不良（ｍｙｏｔｏｎｉｃ ｄｙｓｔｒｏｐｈｙ，ＤＭ）家系分子检测的结果，以及ＣＴＧ三核苷酸重复拷贝数与临床表现的关系。方法 用长模板护展＾ＴＭＰＣＲ法检测一个ＤＭ家系，２３名受栓者１９ｑ１３．２－３上肌张力蛋白激酶基因（ＭＴＰＫ）３’端非翻译区上ＣＴＧ重复拷贝数。结果 临床８例典型的ＤＭ患者中４例ＣＴＧ重复序列异常护展，另４例ＣＴＧ重复拷贝数正常。８例临床可疑的ＤＭ

DNA analysis of a pedigree with myotonic dystrophy in Songjiang county,Shanghai

OBJECTIVE: To make the molecular analysis of a pedigree with myotonic dystrophy (DM) in Songjiang county, Shanghai, and to observe the connection between CTG repeat number and clinical features. METHODS: In twenty-three individuals of a pedigree with DM, CTG trinucleotide repeat numbers located in the 3' untranslated region of a protein kinase gene (MTPK) on chromosome 19q13.2-3 were analyzed by using Long Expand TM Template PCR system. RESULTS: Four of eight clinical patients had expanded DM allele, the other four had no expanded CTG copies. Seven of eight suspicious DM cases had expanded CTG repeat numbers and were therefore genetically diagnosed as DM, and an asymptomatic individual was diagnosed as a doubted DM patient by DNA analysis. High risk of DM in six of seven individuals was ruled out, and a clinical doubted DM individual was ascertained a normal person by molecular analysis. A positive correlation was found beween early onset and expanded CTG repeat number in six parents (or grandparents)/child pairs, but in the pair II 2 /IV 7 CTG repeat numbers were reduced from 3100 in the grandmother to 175 in her grandson and there was no anticipation phenomenon. CONCLUSION: The measurement of CTG repeat number can help to ascertain the diagnosis of DM in clinical and preclinical patients, but some clinically- diagnosed DM patients might have normal CTG repeat numbers. Anticipation phenomena were common in the pedigree.