Chromosomal microarray analysis in pregnancies with prenatal ultrasound abnormalities according to the involved organ systems

Purpose: Chromosomal microarray (CMA) is a high-resolution technique that can identify submicroscopic chromosomal aberrations or copy number variants (CNVs). We aimed to analyze the frequency of significant CNVs according to the involved organ systems in fetuses with ultrasound-detected abnormalities. Materials and Methods: This study was a retrospective observational study. We conducted the study between April 2019 and July 2023, including fetuses with abnormal ultrasound findings and normal karyotyping results. We analyzed the CNVs results according to organ systems. Results: A total of 346 prenatal CMA were performed during the study periods, and there were 164 (47.4%) cases with abnormal ultrasound findings. In 9 (5.5%) of the 164 cases with a normal karyotype, significant CNVs were detected. The frequency of significant CNVs was higher in cases involving multiple organ systems than in single organ systems (12.5% vs. 5.1%). The distribution of significant CNVs by single organ systems was as follows: genitourinary 16.7% (1/6), face and neck 16.7% (1/6), cardiac 7.7% (1/13), early-onset fetal growth restriction 7.7% (1/13), and increased nuchal translucency 4.6% (4/87). Conclusion: We confirmed that prenatal CMA is a useful diagnostic tool in cases of ultrasound abnormalities. Additionally, we demonstrated that the frequency of significant CNVs varies according to the organ systems. We expect that collecting and analyzing more cases will aid in improving for prenatal CMA when there are ultrasound abnormalities are detected.