Lugthart Malou A, Horenblas Judith, Kleinrouweler Emily C, Engels Melanie, Knegt Alida C, Huijsdens Karin, van Leeuwen Elisabeth, Pajkrt Eva
Department of Obstetrics and Gynecology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Department of Obstetrics and Gynecology, Amsterdam UMC, VU University, Amsterdam, The Netherlands.
Prenat Diagn. 2020 May;40(6):705-714. doi: 10.1002/pd.5666. Epub 2020 Mar 3.
To describe the prenatal sonographic features and maternal biochemical markers in triploid pregnancies and to assess whether prenatal phenotype can determine genetic origin.
We performed a retrospective multicenter cohort study that included all triploid pregnancies diagnosed between 2000 and 2018 in two Fetal Medicine Units in Amsterdam. Fetal growth, presence of structural anomalies, extra-fetal anomalies, and maternal biochemical markers were retrieved. Asymmetrical intrauterine growth restriction was diagnosed when the head-to-abdominal circumference (HC/AC) ratio was >95th centile. Parental origin was analyzed via molecular genotyping in 46 cases (38.3%).
One hundred and twenty triploid pregnancies were identified, of which 86 cases (71.6%) were detected before 18 weeks of gestation. Triploidy of maternal origin was found in 32 cases (69.6%) and was associated with asymmetrical growth restriction, a thin placenta, and low pregnancy-associated plasma protein A and free beta-human chorionic gonadotrophin (β-hCG) levels. Triploidy of paternal origin was found in 14 cases (30.4%) and was associated with an increased nuchal translucency, placental molar changes, and a high free β-hCG. Prospective prediction of the parental origin of the triploidy was made in 30 of the 46 cases based on phenotypical ultrasound presentation, and it was correct in all cases.
Asymmetrical growth restriction with severe HC/AC discrepancy is pathognomonic of maternal triploidy. Placental molar changes indicate a paternal triploidy. Moreover, triploidy can present with an abnormal first trimester combined test, with serum levels on the extreme end. When available results of maternal serum markers can support the diagnosis of parental origin of the triploidy, an accurate assessment of the parental origin based on prenatal sonographic features is possible, making DNA analysis redundant.
描述三倍体妊娠的产前超声特征和母体生化标志物，并评估产前表型是否能确定遗传起源。
我们进行了一项回顾性多中心队列研究，纳入了2000年至2018年期间在阿姆斯特丹的两个胎儿医学科室诊断出的所有三倍体妊娠病例。记录胎儿生长情况、结构异常的存在、胎儿外异常情况以及母体生化标志物。当头围与腹围（HC/AC）比值大于第95百分位数时，诊断为不对称性宫内生长受限。对46例（38.3%）病例通过分子基因分型分析亲代起源。
共识别出120例三倍体妊娠，其中86例（71.6%）在妊娠18周前被检测到。母源性三倍体在32例（69.6%）中被发现，与不对称生长受限、胎盘薄以及妊娠相关血浆蛋白A和游离β-人绒毛膜促性腺激素（β-hCG）水平低有关。父源性三倍体在14例（30.4%）中被发现，与颈项透明层增厚、胎盘水泡样改变以及高游离β-hCG有关。基于表型超声表现，在46例中的30例对三倍体的亲代起源进行了前瞻性预测，所有病例预测均正确。
伴有严重HC/AC差异的不对称生长受限是母源性三倍体的特征性表现。胎盘水泡样改变提示父源性三倍体。此外，三倍体妊娠在孕早期联合检测时可能出现异常，血清水平处于极端情况。当母体血清标志物的现有结果能够支持三倍体亲代起源的诊断时，基于产前超声特征对亲代起源进行准确评估是可行的，从而无需进行DNA分析。
