利用21号染色体上STR位点进行唐氏综合征基因诊断的研究

Genetic diagnosis of Down's syndrome using the STR of 21 chromosome

【目的】探讨利用21号染色体上STR位点进行唐氏综合征基因诊断的可行性,建立一种快速、准确、简便的唐氏综合征基因诊断方法。【方法】以18例唐氏综合征为研究对象,选择21号染色体上3个STR位点(D21S2052、D21S2054、D21S1446),对外周血DNA进行PCR扩增与聚丙烯酰胺凝胶电泳,根据STR位点出现三条密度定量之比为1∶1∶1带型(完全杂合型)或两条2∶1带型(半杂合型)诊断唐氏综合征,与此同时以细胞遗传学染色体核型分析作为对照。【结果】18例患者在3个STR位点全部出现1∶1∶1带型或2∶1带型,基因诊断结果与染色体核型分析一致。【结论】21号染色体上3个STR位点的基因分型和PCR扩增方法,快速、准确、简便,可用于唐氏综合征基因诊断。

[Objective] To discuss the feasibility of genetic diagnosis of Down＇s syndrome using the STR of 21 chromosome and establish a rapid, accurate and fast way diagnosing the Down＇s syndrome. [Methods] The DNA samples of 18 Down＇s syndrome were amplified by PCR and polyacrylamide gel electrophoresis. The diagnosis was made by analyzing allelic distribution at 3 STR locus（D21S2052. D21S2054. D21S1446）. In contrary to the karyotype analysis at the same time. [Results] All the 18 cases appeared three bands with ratio of 1 ： 1 ： 1 or two bands with ratio of 2 ： 1 in the sites of chosen STRs,which was coincident with the analysis of karyotype. [Conclusion] The method of PCR amplification of the three STR locus in the 21 chromosome is rapid, accurate and simple for genetic diagnosis of Downs syndrome.