A Quality Assurance Scheme for Prenatal Detection of Aneuploidy Based on Developing Chimeric Quality-Control Cells.

Background: The shortage of quality-control materials caused by non-renewable utilization of rare disease samples is the key factor to limit the quality control of prenatal molecular diagnosis. This study aimed to prepare aneuploid amniocyte lines for the development of quality control cells for fluorescence in situ hybridization (FISH)-mediated detection of aneuploidy.

Methods: Recombinant SV40LTag-pcDNA3.1(-) vectors were transfected into 47,XY,+18 amniotic fluid cells with the use of liposomes. After culturing, these cells were mixed with primary amniocytes with the karyotype 46,XY to prepare four groups of chimeric quality control cells comprising recombinant cells with the karyotypes 47,XY,+18 and primary cells with 46,XY, with theoretical ratios of 47,XY,+18 cells at 5%, 10%, 20%, and 40%. Subsequently, the chimeric quality control cells were tested as clinical samples by three technicians to examine their feasibility for use as internal quality controls (IQC) for FISH detection.

Results: After being immortalized by the SV40 large T antigen gene (SV40LT), these aneuploid amniocytes can be cultured indefinitely to prepare chimeric quality control cells. The actual ratio of the 47,XY,+18 cells was identified by FISH to be 1.5 ± 1.1%, 10.3 ± 1.0%, 19.9 ± 0.4%, and 40.8 ± 0.3%, respectively, and the fluorescence signals of chromosomes 13, 18, 21, X, and Y in these cells were consistent with that of the primary cells.

Conclusions: The present study may resolve the shortage of quality control cells in the prenatal detection of chromosomal aneuploidy and may provide a foundation for IQC-based detection in FISH.