The major cause of first-trimester pregnancy loss is chromosomal abnormality, which could be detected by many methods. Conventional karyotyping based on chorionic villi (CV) culture is frequently used but may have limitations due to culture failure and selective growth of cells. In this study, we aimed to investigate the degree of mosaicism present in villi by a combination of three different methods, namely conventional karyotyping following culture, multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridization (FISH), with a view to exploring the incidence of selective growth of mosaic CV cells during the process of culture for conventional karyotyping. CV samples were obtained from 207 patients with early spontaneous miscarriage (ESM). There were 56 (56/207, 27.1%) samples with mosaic chromosome detected by FISH based on four or five types of probes in this study. The incidence of selective growth of mosaic cells during the process of conventional karyotyping was 6.0% (11/183). In addition, we found that mosaic cell lines as low as 2% could grow and completely dominate the outcome of karyotyping results. The selective growth of a particular cell line during culture, whether euploidy or aneuploidy, could supress the diagnosis of mosaicism.

中文翻译：

---

通过常规核型分型在绒毛膜绒毛的染色体分析中选择性生长镶嵌细胞。

孕早期丢失的主要原因是染色体异常，可以通过许多方法检测到。常规使用基于绒毛膜绒毛（CV）培养的常规核型分析，但由于培养失败和细胞选择性生长而可能存在局限性。在这项研究中，我们旨在通过三种不同方法的结合来研究绒毛中存在的镶嵌程度，即传统的培养后染色体核型分析，多重连接依赖探针扩增（MLPA）和荧光原位杂交（FISH），以期探索在进行常规核型分析的过程中镶嵌CV细胞选择性生长的可能性。CV样本是从207例早期自然流产（ESM）患者中获得的。有56（56/207，27。本研究基于四种或五种类型的探针，通过FISH检测到1％的具有镶嵌染色体的样本。在常规核型分析过程中，镶嵌细胞选择性生长的发生率为6.0％（11/183）。此外，我们发现低至2％的镶嵌细胞系可能生长并完全支配核型分析结果。培养过程中特定细胞系的选择性生长，无论是整倍体还是非整倍体，都可能妨碍镶嵌术的诊断。