STR-PCR检测唐氏综合征额外21号染色体亲源性及不分离时期

摘要

Objective To identify the parental origin of the extra chromosomes,as well as the stage of nondisjunction by STR-PCR ,so as to investigate the etiology of Down syndrome. Methods In 2003～2004, 10 patients with Down syndrome and their parents from Guangzhou were detected by STR-PCR with D21s11,D21S1412 and D21s1411,which was within or near the Down syndrome critical region (DSCR). Results Of the 10 cases Down syndrome patients,parental origin was maternal in 8 cases,of which 7 derived from the nondisjunction in the meiotic Ⅰ (MⅠ) period,1 occurred in meiotic Ⅱ (MⅡ) period. Conclusion STR-PCR technique could effectively identify the parental origin of extra chromosome and the stage of nondisjunction in Down syndrome patients. The majority of Down syndrome is from the maternal nondisjunction in meiotic Ⅰ (MⅠ) period,and advanced maternal age is one of the important factors.%目的 应用短串联重复序列-聚合酶链反应(STR-PCR)方法对唐氏综合征的额外21号染色体的亲源性及不分离时期进行判定,初步探讨唐氏综合征的发病机制.方法 2003～2004年收集来自广州地区的10个唐氏综合征患者及其父母共30人,选取21号染色体上唐氏综合征致病关键区域(DSCR)内部及其附近的3个STR位点(D21S11,D21S1412,D21S1411)对其分别进行检测.结果 在10个唐氏综合征患者中,除2个因位点纯合或父母子三方扩增片段大小相同而不能判断外,8个患者确定了额外21号染色体的亲源性,均为母源性的,其中7个发生在减数分裂I(MI)期,1个发生在减数分裂II(MII)期.结论 STR-PCR方法能确定大多数唐氏综合征患者额外染色体的亲源性及不分离时期.多数唐氏综合征患者的额外21号染色体源于母源性减数分裂I(MI)期的不分离,母亲高龄是唐氏综合征发病的一个高发因素.