限制性胎盘嵌合临床病理及分子遗传学分析

Clinicopathological and molecular genetic features of confined placental mosaicism

目的探讨限制性胎盘嵌合(confined placental mosaicism,CPM)的分子遗传与临床病理特征及其对胎儿宫内发育的影响。方法收集北京市海淀区妇幼保健院2018年5月至2022年3月确诊的14例CPM,对胎盘标本进行分子遗传和病理学检查,并进行临床病理学分析。结果产妇年龄27~34岁,平均年龄(30.0±3.54)岁,孕周35+1~41+2周。4例早产,10例足月产,其中女胎儿6例,男胎儿8例。9例(9/14)出现了不良妊娠结局,其中7例为胎儿生长受限。CPM胎盘重量减轻,其中6例重量小于第10百分位数,5例重量位于第10~25百分位数之间。14例CPM胎盘均出现不同程度的灌注功能障碍形态学变化,以胎盘-母体血管灌注功能障碍为主,其次为胎盘-胎儿血管灌注功能障碍。不同CPM病例嵌合染色体各异,以16-三体/单体嵌合常见,其次为7-三体和21-三体/单体嵌合。同一个CPM胎盘不同部位嵌合比例不等,脐带、胎膜、胎儿面、母体面和边缘嵌合比例波动范围为1%~70%。结论不同CPM病例嵌合染色体各异,同一CPM胎盘不同部位嵌合比例不等,病理形态学以灌注功能障碍为主要表现,可导致胎儿生长受限、早产等不良妊娠结局发生。

Objective To investigate the clinicopathological and genetic features of confined placental mosaicism(CPM)and its effect on fetal intrauterine growth.Methods Fourteen CPM cases of Haidian Maternal and Children Health Hospital were collected from May 2018 to March 2022.Clinicopathological examination on placental specimens and molecular genetic analysis were performed.Results The age of the parturient women ranged from 27 to 34 years,with an average age of(30.0±3.54)years.The gestational weeks ranged from 35+1 to 41+2 weeks.There were 4 premature births and 10 term births,among which 6 were female and 8 were male fetuses.Nine cases(9/14)had adverse pregnancy outcomes,including 7 cases of fetal growth restriction.The weight of CPM placenta decreased,with 6 cases below the 10th percentile of weight standards and 5 cases between the 10th and 25th percentile.All 14 CPM placental specimens showed morphological changes of perfusion dysfunction to varying degrees,with mainly placental-maternal vascular malperfusion followed by placental-fetal vascular malperfusion.The mosaic chromosomes in different CPM cases varied,with 16-trisomy/monosomy mosaicism being the most common followed by 7-trisomy and 21-trisomy/monosomy mosaicism.The mosaic proportion was unequal in different parts of the same CPM placenta,with the mosaic proportion of umbilical cord,fetal membranes,fetal surface,maternal surface,and edge ranging from 1%to 70%.Conclusions The mosaic chromosomes in different CPM cases vary,and the mosaic proportion is unequal in different parts of the same CPM placenta.The pathological morphology is mainly manifested as perfusion dysfunction,which can lead to adverse pregnancy outcomes such as fetal growth restriction and preterm birth.