目的 初步探讨嵌合型22-三体胎儿的临床特征。方法 回顾性分析2017年1月至2018年11月在本院医学遗传中心确诊的3例嵌合型22-三体胎儿的产前诊断结果和妊娠结局。结果 3例胎儿羊水染色体G显带分析结果中有2例是嵌合型22-三体，1例是正常核型结果46,XX；3例胎儿羊水荧光原位杂交检测结果中，1例未做荧光原位杂交检测，1例结果提示胎儿为22-三体嵌合体，1例结果提示胎儿22号染色体数目正常；3例胎儿羊水染色体微阵列分析结果中，1例结果提示胎儿22号染色体存在拷贝数中性的杂合性丢失，2例结果提示2个胎儿均为22-三体嵌合体。结论 嵌合型22-三体胎儿的临床特征缺乏特异性，使用单一的方法进行检测有可能发生漏诊，对于产前筛查怀疑是22-三体的胎儿应进行多种方法同时检测，对于产前诊断确诊为嵌合型22-三体的胎儿，应对胎儿预后进行多学科会诊评估。
Objective To explore the clinical application of cytogenetic techniques combined with chromosomal microarray and fluorescence in situ hybridization in the prenatal diagnosis of mosaic trisomy 22 fetal. Methods Retrospective analysis the prenatal diagnosis results and pregnancy outcomes of 3 mosaic trisomy 22 fetus diagnosed by the Medical Genetics Center of Guangdong Women and Children Hospital from January 2017 to November 2018. Results Among the 3 amniotic fluid karyotyping results, 2 cases were mosaic trisomy 22, and 1 case was normal karyotype 46,XX. Among the 3 amniotic fluid fluorescence in situ hybridization test results, 1 case did not undergo the FISH test, 1 case indicated that the fetus was mosaic trisomy 22, and 1 case indicated that the number of chromosome 22 was normal. Among the analysis results of amniotic fluid Chromosomal microarray in 3 fetuses, the results of 1 case indicated that cnLOH was present on chromosome 22, and the results of 2 cases indicated that both fetuses were mosaic Trisomy 22. Conclusions The clinical characteristics of mosaic Trisomy 22 fetus are lack of specificity, detection using a single method may lead to missed diagnosis, multiple methods should be used to detect the fetus that is suspected to be a mosaic trisomy 22 fetus in prenatal screening, and multi-disciplinary team consultation and evaluation should be conducted on the prognosis of the fetus that is confirmed to be a mosaic Trisomy 22 fetus in prenatal diagnosis.
