通过聚合酶链反应相关分析21号染色体上的小串联重复序列和S100B实现21三体综合征的快速产前诊断。

Rapid prenatal diagnosis of trisomy 21 by polymerase chain reaction- associated analysis of small tandem repeats and S100B in chromosome 21.

作者信息

Yang Y H, Kim I K, Oh S H, Kim C K, Kim J Y

机构信息

Department of Obstetrics and Gynecology, Prenatal Clinic, College of Medicine, Yonsei University, Seoul, Korea.

出版信息

Fetal Diagn Ther. 1998 Nov-Dec;13(6):361-6. doi: 10.1159/000020870.

DOI:10.1159/000020870

PMID:9933820

Abstract

OBJECTIVES

The incidence of Down syndrome increases with maternal age and a rapid and accurate method for prenatal diagnosis is a necessity. This study was devised to evaluate and compare the methods for detecting trisomy 21 by polymerase chain reaction (PCR)-associated analysis of small tandem repeats (STR) of D21S11 and semiquantitative analysis of S100B of chromosome 21.

METHODS

PCR was performed with DNA template obtained from 20 normal samples (10 blood, 10 amniotic fluid) and 12 Down syndrome samples (10 blood, 2 amniotic fluid). 32P-labelled primers for D21S11 and S100B were used. PCR products for D21S11 were subjected to polyacrylamide urea gel (6%) electrophoresis, followed by exposure to X-ray film, and then the densities of signals were recorded by densitometer. PCR products for S100B and insulin-like growth factor-I (IGF-I) as an internal control were subjected to agarose gel (2%) electrophoresis and the relative amounts of radioactivity in their products were measured to assess the quantitation of template DNA.

RESULTS

Analysis of D21S11 STR showed equivalent triplets in 4 cases and unequivalent doublets (1:2) in 8 Down syndrome samples. The normal control group showed singlets in 5 cases and equivalent doublets in 15 cases. In the analysis of S100B, the ratios of S100B to IGF-I was 1.4-1.6 in 7 of 12 Down syndrome samples, while the ratios of S100B in all normal samples were close to 1.0. All the results were obtained within 24 h. The D21S11 STR analysis managed to distinguish more clearly between normal and trisomy 21, while semiquantitative PCR analysis of S100B was less able to assess trisomy 21.

CONCLUSION

Prenatal diagnosis of trisomy 21 by PCR-associated STR analysis of D21S11 and semiquantitative analysis of S100B are useful, innovative, accurate and rapid diagnostic methods, while D21S11 STR analysis is more discriminating in detecting trisomy 21 and also may be employed in preimplantation diagnosis of Down syndrome.

摘要

目的

唐氏综合征的发病率随母亲年龄增长而增加，因此需要一种快速准确的产前诊断方法。本研究旨在评估和比较通过聚合酶链反应（PCR）相关分析21号染色体上小串联重复序列（STR）D21S11以及对21号染色体上S100B进行半定量分析来检测21三体的方法。

方法

使用从20份正常样本（10份血液、10份羊水）和12份唐氏综合征样本（10份血液、2份羊水）中获取的DNA模板进行PCR。使用针对D21S11和S100B的32P标记引物。D21S11的PCR产物进行6%聚丙烯酰胺尿素凝胶电泳，随后进行X射线胶片曝光，然后用密度计记录信号密度。S100B以及作为内对照的胰岛素样生长因子-I（IGF-I）的PCR产物进行2%琼脂糖凝胶电泳，并测量其产物中的放射性相对量以评估模板DNA的定量。

结果

对D21S11 STR的分析显示，在4例中为等效三联体，在8例唐氏综合征样本中为不等效二联体（1:2）。正常对照组在5例中显示为单联体，在15例中显示为等效二联体。在对S100B的分析中，12例唐氏综合征样本中的7例S100B与IGF-I的比值为1.4 - 1.6，而所有正常样本中S100B的比值均接近1.0。所有结果均在24小时内获得。D21S11 STR分析能够更清晰地区分正常与21三体，而S100B的半定量PCR分析评估21三体的能力较弱。