Abstract：
Placental mesenchymal dysplasia (PMD) is characterized by placentomegaly, aneurysmally dilated chorionic plate vessels, thrombosis of the dilated vessels, and large grapelike vesicles, and is often mistaken for partial or complete hydatidiform mole with a coexisting normal fetus. Androgenetic/biparental mosaicism (ABM) has been found in many PMD cases. Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder with complex and diverse phenotypes and an increased risk of developing embryonal tumors. There are five major causative alterations: loss of methylation of imprinting control region 2 (KCNQ1OT1:TSS-DMR) (ICR2-LOM), gain of methylation at ICR1 (H19/IGF2:IG-DMR) (ICR1-GOM), paternal uniparental disomy of 11 (pUPD11), loss-of-function variants of the CDKN1C gene, and paternal duplication of 11p15. Additional minor alterations include genetic variants within ICR1, paternal uniparental diploidy/biparental diploidy mosaicism (PUDM, also called ABM), and genetic variants of KCNQ1. ABM (PUDM) is found in both conditions, and approximately 20% of fetuses from PMD cases are BWS and vice versa, suggesting a molecular link. PMD and BWS share some molecular characteristics in some cases, but not in others. These findings raise questions concerning the timing of the occurrence of the molecularly abnormal cells during the postfertilization period and the effects of these abnormalities on cell fates after implantation.
摘要：
胎盘间充质发育不良（PMD）的特征是胎盘肿大，动脉瘤扩张的绒毛膜板血管，扩张血管的血栓形成，和大的葡萄状囊泡，常被误认为部分或完全葡萄胎与正常胎儿共存。在许多PMD病例中发现了雄激素/双亲镶嵌（ABM）。Beckwith-Wiedemann综合征（BWS）是一种具有复杂和多样表型的印记障碍，并且发展为胚胎性肿瘤的风险增加。有五个主要的致病改变：印迹控制区2（KCNQ1OT1：TSS-DMR）（ICR2-LOM）的甲基化丧失，在ICR1（H19/IGF2：IG-DMR）（ICR1-GOM）处获得甲基化，父系单亲11（pUPD11），CDKN1C基因的功能缺失变异体，和父系复制11p15。其他较小的改变包括ICR1内的遗传变异，父系单亲二倍体/双亲二倍体镶嵌性（PUDM，也称为ABM)，和KCNQ1的遗传变异。ABM(PUDM)在这两种情况下都有，大约20%的来自PMD病例的胎儿是BWS，反之亦然，暗示了一种分子联系.在某些情况下，PMD和BWS具有一些共同的分子特征，但不是在别人。这些发现提出了有关受精后分子异常细胞发生的时间以及这些异常对植入后细胞命运的影响的问题。
