目的：目前，临床应用荧光原位杂交（FISH）法诊断唐氏综合征多采用血液及皮肤活检组织，属于有创检查。该研究探讨应用FISH方法检测口腔黏膜细胞（无创取材）对唐氏综合征的诊断价值。方法：应用FISH方法对2010年3月至2011年3月16例可疑唐氏综合征患儿外周血及口腔黏膜脱落细胞进行检测分析；同时进行外周血淋巴细胞染色体核型分析。结果：FISH法检测外周血及口腔黏膜脱落细胞标本，显示14例为21-三体综合征，2例21号染色体数目正常，结果与外周血染色体核型分析结果一致。结论：应用FISH方法对口腔黏膜脱落细胞标本进行检测可为唐氏综合征的准确、无创性诊断提供新的检测途径。

OBJECTIVE: At present, blood and skin biopsy tissues are used in the fluorescent in situ hybridization (FISH) test for the diagnosis of Down's syndrome, however, the samples are usually obtained invasively. This study explores the value of oral mucosa cast-off cells in the FISH test, as samples obtained non-invasively, for the diagnosis of this disorder. METHODS: Peripheral blood and oral mucosa cast-off cells were sampled for the FISH test in 16 children with suspected Down's syndrome between March 2010 and March 2011. Chromosomal karyotype analysis of peripheral blood lymphocytes ("gold standard" for the diagnosis of Down's syndrome) was also conducted. RESULTS: The FISH test, in which both peripheral blood and oral mucosa cast-off cells were examined, showed that 14 children had 21-trosomy syndrome and the other 2 children had normal numbers of cromosome 21. The results of the FISH test were the same as the results of the chromosomal karyotype analysis. CONCLUSIONS: Use of the FISH method to test samples of oral musoca cast-off cells is non-invasive and reliable for the diagnosis of Down's syndrome in children, and is hence worthy of recommendation.