PDF(Pubmed)
Abstract：
It is now well established that maternal serum markers are often abnormal in fetal trisomy 21. Their determination is recommended for prenatal screening and pregnancy follow-up. However, mechanisms leading to abnormal maternal serum levels of such markers are still debated. Our objective was to help clinicians and scientists unravel the pathophysiology of these markers via a review of the main studies published in this field, both in vivo and in vitro, focusing on the six most widely used markers (hCG, its free subunit hCGβ, PAPP-A, AFP, uE3, and inhibin A) as well as cell-free feto-placental DNA. Analysis of the literature shows that mechanisms underlying each marker\'s regulation are multiple and not necessarily directly linked with the supernumerary chromosome 21. The crucial involvement of the placenta is also highlighted, which could be defective in one or several of its functions (turnover and apoptosis, endocrine production, and feto-maternal exchanges and transfer). These defects were neither constant nor specific for trisomy 21, and might be more or less pronounced, reflecting a high variability in placental immaturity and alteration. This explains why maternal serum markers can lack both specificity and sensitivity, and are thus restricted to screening.
摘要：
现在已经确定，母体血清标志物在胎儿21三体中通常是异常的。建议将其确定用于产前筛查和妊娠随访。然而,导致这些标志物异常的母体血清水平的机制仍存在争议。我们的目标是帮助临床医生和科学家通过回顾发表在这一领域的主要研究来解开这些标志物的病理生理学。在体内和体外，专注于六种最广泛使用的标志物(hCG，其游离亚基hCGβ，PAPP-A,法新社,uE3和抑制素A）以及无细胞胎盘DNA。文献分析表明，每个标记的调节机制是多重的，不一定与21号染色体直接相关。还强调了胎盘的关键参与，它的一个或几个功能可能有缺陷(周转和凋亡，内分泌生产，以及生母交流和转移)。这些缺陷既不是恒定的，也不是特定的21三体，可能或多或少明显，反映胎盘不成熟和改变的高度变异性。这解释了为什么母体血清标志物缺乏特异性和敏感性，因此仅限于筛查。
