ABSTRACT
Objective To set a rapid,simple gene diagnosis method for Down syndrome.Methods Three short tandem repeats(D21S11,D21S1270,D21S1437)loci in or near Down syndrome critical region(DSCR) were analyzed and detected by polymerase chain reaction and DNA quantitative analysis in 11 core ancestry.Results There were four types by DNA quantitative analysis to different individuals at a short tandem repeats(STR) locus.In type one,a homozygote of one allelic gene was detected.In type two,a normal heterozygote of two allelic genes was found,the content or two DNA electrophoresis bands was approximately 1∶1.In type three,a Down syndrome patient of two allelic genes was discovered.The quantity of two electrophoresis bands was nearly 2∶1.In type four,the patient showed three DNA electrophoresis bands which the content was approximately 1∶1∶1.Conclusion A rapid gene diagnosis and prenatal diagnosis method for Down syndrome can be used for quantitative analysis of STR polymorphism loci.