333例懷孕中期羊水細胞染色體核型分析

Analysis of Fetal Karyotypes from 333 Cases of Amniocentesis

目的：分析妊娠中期進行產前診斷的高危險群孕婦羊水細胞染色體核型，了解此期異常核型出現的頻率、類型及與各種產前診斷適應症的關係。方法：由2007 至2009 年收集了333 例有產前診斷適應症的孕婦（1 例為雙胞胎妊娠），妊娠在16～24 週，以超音波定位下進行羊膜腔穿刺術，抽取羊水細胞進行培養及染色體核型分析。結果：發現異常核型8 例，異常核型檢出率為2.40%（8/333），染色體平衡易位最多，佔了37.50%（3/8），其中染色體相互易位1 例，佔異常核型的12.50%（1/8），羅伯森易位2 例，佔25%（2/8）；染色體倒轉2 例，佔異常核型25%（2/8）；染色體21 三染色體症及透納氏症各1 例，均佔12.50%（1/8）；額外標誌染色體1 例（47,XY,+mar mat），佔12.50%（1/8）。結論：有各種產前診斷適應症的高危險群孕婦中，胎兒染色體異常核型的發生率為2.40%（8/333），染色體易位、唐氏症、缺失及倒轉是懷孕中期的主要染色體異常核型。

Objective: To analyze the fetal karyotypes in prenatal diagnosis and the relationship between abnormal karyotypes and the indications of prenatal diagnosis. Methods: Fetal chromosomal karyotypes were examined in 333 pregnant women (16 to 24 weeks of gestation) by amnioantesis between 2007 and 2009. Results: Eight cases of chromosomal abnormalities were detected, with an abnormality rate of 2.40% (8/333). Balanced chromosomal translocation was the major abnormality, with 3 of the 8 cases (37.50%), including 1 case of reciprocal translocation and 2 cases of Robertsonian translocation. Excluding inversion 9 that had normal variation, there were two cases of inversion, inv (2) and inv (7), detected. Both trisomy 21 and 45,X cases had terminated pregnancies. One case with a maternal inherited marker chromosome had a normal phenotype. Conclusion: The frequency of the fetus abnormal chromosomal karyotype in prenatal diagnosis is 2.40%, and chromosomal translocation, trisomy 21, 45,X, and inversion were the major abnormalities found in this study.