脐带血淋巴细胞染色体核型分析在孕中晚期胎儿染色体异常诊断中的作用研究

Karyotyping analysis on umbilical vein cord blood lymphocytes in middle-late pregnant fetus

目的 评价脐带血淋巴细胞染色体核型分析在孕中晚期胎儿染色体异常诊断中的作用.方法 对临床有产前诊断指征的22 ～ 26周龄孕妇,在B超引导下经脐静脉穿刺抽取脐带血0.5～1 ml,分离外周血淋巴细胞,进行原代培养,收集生长状态良好的细胞,固定、制片、显带,进行染色体核型及数据分析.结果 在1 213例孕中晚期胎儿脐带血中成功培养外周血淋巴细胞1 211例,成功率99.9％.其中异常染色体142例,检出率达11.73％.包括非多态性染色体异常81例（检出率6.68％）,多态性改变61例（检出率5.03％）.非多态性染色体异常中染色体数目异常50例（占总异常数35.21％）,包括嵌合体4例;染色体结构异常31例（占总异常数21.83％）,其中11例易位,17例倒位,3例缺失.结论 基于脐带血淋巴细胞培养的染色体核型分析是孕中晚期产前异常染色体诊断的重要方法,对于减少染色体畸形儿的出生具有重要的意义.

Objective To investigate the significances of karyotyping analysis on umbilical cord vein blood lymphocytes in the diagnosis of abnormal karyotypes in middle to late period of pregnant fetus.Methods A volume （0.5 ～ 1 ml） of umbilical cord vein blood was extracted from pregnant women in third trimester pregnancy with prenatal detection indications,and collected in sterilized anticoagulant tube.Lymphocytes were cultured and collected for karyotyping analysis after fixed and dropped on slides.Data were analyzed statistically.Results Lymphocytes were cultured successfully in 1 211 cases out of total 1 213 cases collected.Totally 142 abnormal karyotypes were found,which includes 81 cases （detection rate 6.68 %） of non-heteromorphic abnormal chromosomes and 61 cases （detection rate 5.03%） of heteromorphic chromosomes.Among these abnormal karyotypes,50 cases （accounting for 35.21% in total abnormal cases） of aneuploidy include 4 cases of chimerical karyotype.Structural abnormalities were found in 31 cases （accounting for 21.83% in total abnormal cases） samples including 11 cases of translocations,17 cases of inversion and 3 cases of deletion.Conclusions Based on our findings,karyotyping analysis on umbilical cord vein blood lymphocytes could be an effective method for detect abnormal karyotypes in middle to late period of pregnant fetus and played an important role in prenatal diagnosis.