Scientific Laboratory of Molecular Genetics, Riga Stradins University , Riga, Latvia.
Egila Gulbja Laboratory , Riga, Latvia.
Syst Biol Reprod Med. 2020 Dec;66(6):410-420. doi: 10.1080/19396368.2020.1827081. Epub 2020 Oct 15.
The analysis of products of conception (POC) is clinically important to establish the cause of early pregnancy loss. Data from such analyses can lead to specific interventions in subsequent natural or assisted conceptions. The techniques available to examine the chromosomal composition of POC have limitations and can give misleading results when maternal cell contamination (MCC) is overlooked. The aim of this study was to develop a protocol for MCC assessment and to formulate POC material handling, testing, and reporting recommendations. Using array comparative genomic hybridization, we tested 86 POC samples, of which 47 sample pairs (DNA extracted from the POC sample and maternal DNA) were assessed for the presence of MCC. MCC was evaluated using an approach we developed, which exploited the genotyping of 14 STR, AMEL, and SRY loci. POC samples showing the clear presence of villi (63.9%) did not contain any signs of the maternal genome and can therefore be reliably tested using conventional methods. The proportion of 46,XX karyotype in the unselected sample batch was 0.39, which fell to 0.23 in visually good samples and was 0.27 in samples having no signs of contamination upon MCC testing. MCC assessment can rescue visually poor samples from being discarded or wrongly genotyped. We demonstrate here that classification based on visual POC material evaluation and MCC testing leads to predictable and reliable POC genetic testing outcomes. Our formulated recommendations covering POC material collection, transportation, primary and secondary processing, as well as the array of pertinent considerations discussed here, can be implemented by laboratories to improve their POC genetic testing practices. We anticipate our protocol for MCC assessment and recommendations will help reduce the misconception regarding the etiology of miscarried fetuses and foster informed decision-making by clinicians and patients dealing with early pregnancy loss.
对妊娠产物（POC）进行分析对于确定早期妊娠丢失的原因具有重要的临床意义。对这些分析数据的研究结果可以为随后的自然或辅助妊娠提供具体的干预措施。目前可用于检查 POC 染色体组成的技术存在局限性，如果忽视了母体细胞污染（MCC），可能会得出错误的结果。本研究旨在制定 MCC 评估方案，并制定 POC 材料处理、检测和报告建议。我们使用阵列比较基因组杂交技术对 86 个 POC 样本进行了测试，其中 47 对样本（从 POC 样本和母体 DNA 中提取的 DNA）用于评估 MCC 的存在情况。我们使用一种方法评估 MCC，该方法利用了 14 个 STR、AMEL 和 SRY 基因座的基因分型。明显存在绒毛的 POC 样本（63.9%）不存在任何母体基因组的迹象，因此可以使用常规方法进行可靠的检测。未筛选样本批次中 46,XX 核型的比例为 0.39，在视觉良好的样本中降至 0.23，在 MCC 检测无污染迹象的样本中降至 0.27。MCC 评估可以挽救那些外观较差的样本，避免它们被丢弃或错误分型。我们在这里证明，基于视觉 POC 材料评估和 MCC 测试的分类可导致可预测和可靠的 POC 遗传测试结果。我们制定的涵盖 POC 材料收集、运输、初级和二级处理以及这里讨论的相关考虑因素的建议，可由实验室实施，以改善其 POC 遗传测试实践。我们预计，我们的 MCC 评估方案和建议将有助于减少对流产胎儿病因的误解，并为处理早期妊娠丢失的临床医生和患者提供明智的决策。
