摘要
目的 分析上海松江区一个强直性肌营养不良 (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 用长模板扩展 TMPCR法检测一个 DM家系、2 3名受检者 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重复序列异常扩展 ,另 4例 CTG重复拷贝数正常。 8例临床可疑的 DM患者中 7例 CTG重复序列过度扩展 ,确诊为 DM患者 ,1名无症状个体为可疑 DM患者。另 6名家系成员有 DM风险的个体及 1名可疑 DM个体确诊为该家系的正常人。家系中 6对父母 (祖父母 ) /子女早现现象明显 ,另 1对无早现现象。结论 分子检测对临床可疑的 DM个体有重要的直接诊断价值 ,但部分临床诊断为 DM患者 CTG重复拷贝数可以是正常的 ,其原因有待进一步探讨。
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.
出处
《中华医学遗传学杂志》
EI
CAS
CSCD
北大核心
2000年第5期319-322,共4页
Chinese Journal of Medical Genetics
