Comparison of chromosomal microarray and karyotyping in prenatal diagnosis using 491 amniotic fluid samples

This study was aimed to investigate the performance of chromosomal microarray analysis (CMA) in prenatal diagnosis compared with traditional karyotyping analysis. Both CMA and karyotyping analyses were performed to detect the karyotypes in the amniotic fluid of 491 pregnant women who got prenatal diagnosis at the Center of Prenatal Diagnosis of Shangrao (China) during January 2019 to April 2021. After excluding 2 samples in the CMA analysis and 2 samples in the karyotyping analysis which were failed in detection, the remaining 487 amniotic fluid samples were detected. Both CMA and karyotyping analyses identified 22 cases of aneuploidy chromosome abnormalities, including trisomy 21 (10 cases), trisomy 18 (4 cases), sex chromosome abnormality (5 cases), and other chromosome abnormalities (3 cases). In addition, CMA and karyotyping analyses found 8 cases of fetal chromosomal imbalance. Interestingly, abnormal results were detected by CMA analysis in 10 cases whose results were normal by karyotype analysis. Furthermore, 23 cases of copy number variation (CNVs) with variation of unknown clinical significance (VOUS) were detected by CMA, which accounted for 4.68% (23/491) in all cases. However, CMA was not able to accurately identify some complex karyotypes and mixed chimeras, including 2 cases of chimeras, 4 cases of balanced translocations, 4 cases of pericentric inversions, and 8 cases of other chromosome polymorphisms, indicating karyotyping analysis was superior to detect these chromosome abnormalities compared with CMA analysis. CMA was better in detecting the fracture sites, microduplication and microdeletion with definite pathogenicity, and CNVs with VOUS compared with karyotype analysis.