体外受精后单绒毛膜双合子双胎活产一例

Live born monochorionic dizygotic twins after in vitro fertilization: a case report

本文报告了 1例经体外受精后B超确诊为单绒毛膜双胎妊娠的病例。该孕妇中孕期随机抽取一胎羊水行荧光原位杂交技术和染色体核型分析检测,未见异常。双胎生后2d和3岁时分别行外周血染色体核型分析检测,提示双胎外周血染色体核型均为21-三体男性和正常女性2种染色体核型嵌合异常(chi 47,XY,+21/46,XX)。3岁时刮取双胎口腔黏膜细胞行单核苷酸多态性基因芯片检测,结果提示男童核型为47,XY,+21,女童为46,XX。以上结果提示该双胎为单绒毛膜双合子双胎,双胎外周血染色体核型均嵌合异常,无组织体细胞染色体核型嵌合异常。男童呈现唐氏综合征患儿特殊面容,女童未见明显异常。

This paper reported a pair of twin babies who were diagnosed as monochorionic (MC) twins (MC) in the first-trimester ultrasound scan after in vitro fertilization. Fluorescence in situ hybridization and chromosomal karyotype analysis of amniotic fluid that was randomly collected from one of the twins were performed in the second trimester, but no abnormality was detected. Chromosome karyotype analysis of peripheral blood of the twins at the age of two days and three years showed that both were chi 47,XY,+21/46,XX. And the single nucleotide polymorphism microarray analysis of oral mucosa cells of the twins at three years old showed that the boy was 47,XY,+21 and the girl was 46,XX. Therefore, we confirmed that they are MC dizygotic twins presenting with blood chimerism but no tissue chimerism. Simply the boy presented with facial features of Down syndrome.