Prenatal detection of CNV variants in fetuses with congenital developmental disorders, from 2015-2020 by MLPA and microarray methods.

Abstract

Aims. Analysis of prenatal samples from 2015 to 2020. Comparison detection rates of clinically relevant variants by cytogenetic karyotype analysis and cytogenomic MLPA and microarray methods.

Material and Methods. 1029 prenatal samples were analyzed by cytogenetic karyotyping (N=1029), cytogenomic methods - MLPA (N=144) and microarray (CMA) (N=111). All unbalanced changes were confirmed by MLPA or CMA.

Results. From the analyzed set of foetuses, after subtraction of aneuploidies - 107 (10.40% N=1029), 22 structural aberrations (2.39% N=922) - nine unbalanced changes (0.98%), 10 balanced changes (1.08%), one case of unclear mosaicism (0.09%), one case of presence of a marker chromosome (0.09%) and one case of sex discordance (0.09%) - were detected by karyotype analysis. A total of eight (7.21% N=111) pathological variants were detected by CMA in 255 samples with physiological karyotype indicated for cytogenomic examination. Five (3.47% N=144) of eight pathogenic variants were detected by MLPA method. The total capture of pathogenic variants by MLPA and CMA methods was 14 (5.14%) and 17 (6.25%) (N=272), including confirmatory pathological karyotype testing. Detection of pathological variants in the isolated disorders group was lower than in the multiple disorders group (5.08% x 21.42%).

Conclusion. A higher success rate for the detection of pathological CNV variants by the microarray method than by the MLPA method was confirmed.