中文摘要：

目的：探索快速诊断21-三体综合征的新方法。方法：应用21号染色体特异性引物对30例智力低下儿童外周血淋巴细胞标本进行引物原位标记（primed in situ labeling，PRINS），同时与传统细胞遗传学核型分析技术进行比较。结果：在间期核和中期分裂相中，PRINS技术均能特异性地检测出21号染色体。在11例21-三体综合征患儿标本中，21号染色体标记率平均为89％；在19例非21-三体综合征患儿标本中，21号染色体标记率平均为93％。荧光杂交信号清晰，整个检测反应在24h内完成。结论：引物原位标记技术可快速、准确地检测21号染色体的数目异常，有助于对传统细胞遗传学检测方法的验证和补充。

英文摘要：

Objective： To explore a new rapid method for the diagnosis of 21 - trisomy syndrome. Methods： The primed in situ labeling （PRINS） reactions with chromosome 21 specific primer were performed on 30 peripheral lymphocyte samples of mental retardation children comparing with chromosome karyotype analysis. Results： The specific chromosomes＇signals were obtained from PRINS on both metaphase and interphase nuclei. In the samples of 21 -trisomy, an average of 89 percent had displayed 3 labeling signals, in the samples of non -21 -trisomy, an average of 93 percent had displayed 2 labeling signals. Conclusion： PRINS is a rapid and specific method for the detection of chromosome 21 ameuploidy.