Abstract
Hydatidiform moles (HMs) are abnormal human pregnancies with vesicular chorionic villi, imposing two clinical challenges; miscarriage and a risk of gestational trophoblastic neoplasia (GTN). The parental type of most HMs are either diandric diploid (PP) or diandric triploid (PPM). We consecutively collected 154 triploid or near-triploid samples from conceptuses with vesicular chorionic villi. We used analysis of DNA markers and/or methylation sensitive-MLPA and collected data from registries and patients records. We performed whole genome SNP analysis of one case of twinning (PP+PM).In all 154 triploids or near-triploids we found two different paternal contributions to the genome (P1P2M). The ratios between the sex chromosomal constitutions XXX, XXY, and XYY were 5.7: 6.9: 1.0. No cases of GTN were observed. Our results corroborate that all triploid human conceptuses with vesicular chorionic villi have the parental type P1P2M. The sex chromosomal ratios suggest approximately equal frequencies of meiosis I and meiosis II errors with selection against the XYY conceptuses or a combination of dispermy, non-disjunction in meiosis I and meiosis II and selection against XYY conceptuses. Although single cases of GTN after a triploid HM have been reported, the results of this study combined with data from previous prospective studies estimate the risk of GTN after a triploid mole to 0% (95% CI: 0–1,4%).
Highlights
Hydatidiform mole (HM) is an abnormal pregnancy characterized by vesicular swelling of the chorionic villi and hyperplasia of the trophoblastic layer [1]
In this study we analyzed all triploid cases from consecutively collected samples from conceptuses suspected of HM in the Danish Mole Project during 25 years
As we did not use a histopathologic diagnosis of hydatidiform mole as an inclusion criterion, our data may not readily be comparable with observations in cohorts delineated by histopathological criteria [1]
Summary
Hydatidiform mole (HM) is an abnormal pregnancy characterized by vesicular swelling of the chorionic villi and hyperplasia of the trophoblastic layer [1]. Most HMs can be classified according to their histological features as either partial (PHM) or complete (CHM) or according to their genomic compositions as either diploid or triploid. Most often the parental type of PHMs is diandric triploids (PPM) and CHMs most often are diandric diploids (PP) [2]. Gestational trophoblastic neoplasia (GTN) is a complication to HM, and approximately 10% of patients with molar pregnancies subsequently are given chemotherapy to treat GTN [3]. PLOS ONE | DOI:10.1371/journal.pone.0142545 November 12, 2015
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