应用定量PCR方法快速基因诊断Down综合征

Rapid detection of trisomy 21 by quantitative polymerase chain reaction

目的探讨用定量聚合酶链反应方法对Ｄｏｗｎ综合征进行基因诊断。方法以短串联重复序列（Ｄ２１Ｓ１１）作为遗传标记，合成特异引物，用同位素标记聚合酶链反应扩增后对１１名正常人（６例外周血，５例羊水）及２８例Ｄｏｗｎ综合征患者（外周血）进行定量检测。结果１１名正常人中１０人出现ＤＮＡ含量为１∶１关系的２条电泳带，１人为１条带。２８例患者中２４人出现ＤＮＡ含量２∶１的２条带，３人为ＤＮＡ含量为１∶１∶１的３条带，１人为１条带。结论Ｄ２１Ｓ１１位点短串联重复序列多态是对Ｄｏｗｎ综合征基因诊断很有应用价值的遗传标记，应用定量聚合酶链反应方法可在２４小时内对Ｄｏｗｎ综合征做出快速、准确的产前及临床基因诊断。

Objective Studying gene diagnosis of trisomy 21 by means of quantitative polymerase chain reaction. Methods Polymorphic short tandem repeat(STR) at D21S11 served as the gene marker, and a pair of primers was synthesized. The samples from 11 normal subjects and 28 cases of trisomy 21 were analyzed by quantitative PCR. Results 10 normal subjects showed two bands with a ratio of 11, and a subjects showed one band. Of 28 cases of trisomy 21,24 cases showed two bands with a ratio of 21,3 cases showed three bands with a ratio of 111, and 1 case showed one band. Conclusion Polymorphic STR at D21S11 is a valuable gene marker for diagnosis of trisomy 21.Trisomy 21 can be diagnosed rapidly and accurately within 24 hours by quantitative PCR.