目的人21号染色体DNA涂染探针的制备及其应用于唐氏综合征诊断的研究。方法将显微分离的人21号染色体DNA进行简并寡核苷酸引物PCR(Degenerate Oligonucleotide Primed-PCR,DOP-PCR)扩增并标记制备成杂交探针后,与15例唐氏征疑似患者的外周血细胞核染色体进行荧光原位杂交(Fluorescence in situ hybridization,FISH)分析;同时以常规核型分析进行确诊并评估FISH结果。结果FISH分析诊断结果与常规核型分析一致,其中8例为非唐氏征患者,7例为唐氏征患者,准确率为100%,且非唐氏征患者与唐氏征患者细胞核中21号染色体的检出率分别高达99.12%和99.08%。结论制备的人21号全染色体DNA涂染探针能精确检测人类中期和间期细胞核中21号染色体的数目,该探针可用于唐氏综合征的诊断。 Preparation of 21 human chromosomal DNA probe and its application in the diagnosis of Down Syndrome. Methods The microsatellite DNA was cloned and sequenced by Degenerate Oligonucleotide Primed-PCR (DOP-PCR). After hybridization, The peripheral blood nuclear chromosomes were analyzed by Fluorescence in situ hybridization (FISH). At the same time, the routine karyotype analysis was used to confirm the FISH results. Results The results of FISH analysis were consistent with those of conventional karyotype analysis. Among them, 8 were non-Down syndrome patients and 7 were Down syndrome patients with an accuracy of 100%. In non-Down syndrome patients and Down syndrome patients, 21 The detection rate of chromosome number was up to 99.12% and 99.08% respectively. Conclusion The prepared human chromosome 21 DNA probe can accurately detect the number of chromosome 21 in human metaphase and interphase nucleus. This probe can be used for the diagnosis of Down’s syndrome.