Impact of In Vitro Cell Subculture on Mosaicism: Comparative Analysis of Chromosome Microarray and Karyotype Results

Abstract Background Prenatal chromosomal abnormality detection traditionally relies on conventional karyotyping. This study explores the impact of in vitro cell subculture on prenatal diagnostic sample results, comparing cell subculture methods and chromosome microarray analysis (CMA). Methods We analyzed G-banding karyotyping data and CMA results from 2007 cases subjected to amniocentesis. This involved examining chromosome mosaicism. Results Chromosome mosaicism was detected by CMA in 1.49% of cases (30/2007). Sex chromosome mosaicism was the most common form of mosaicism. Among the 30 mosaicisms, 18 results were consistent between the two methods. In four cases, CMA indicated mosaicismbut the karyotypes were normal. In eight cases, CMA was normal while the karyotypes suggested mosaicism. Conclusions Our findings suggest that shorter mosaic markers may go unnoticed due to limited resolution in G-banding karyotype analysis via subculture of adherent cells. CMA is capable of detecting regions of homozygosity mosaicism, which may escape karyotype analysis. In vitro cell subculture can lead to the loss of abnormal acentric fragments, potentially contributing to fetal malformations. Furthermore, subculture of adherent cells may lead to pseudo-tetraploid formation, possibly attributed to cell duplication during subculture. CMA mitigates the generation of pseudo-mosaicism associated with subculture (double-line culture). The combined use of karyotyping and CMA enhances the accuracy of prenatal genetic diagnosis, enabling the detection of chromosome mosaicism that may be missed after subculture of adherent cells.