ENHANCING PRENATAL DIAGNOSTIC YIELD OF CHROMOSOMAL ABNORMALITIES BY COMBINED IMPLEMENTATION OF ARRAY-CGH AND TRADITIONAL KARYOTYPING AT HANOI OBSTETRICS AND GYNECOLOGY HOSPITAL

Background: While karyotyping remains the gold standard for prenatal diagnosis of chromosomal abnormalities, it is limited to detecting alterations larger than 5 Mb (over 5 million base pairs). In contrast, array CGH (Microarray-based Comparative Genomic Hybridization) provides a comprehensive analysis of all 24 chromosomes, enabling the detection of chromosomal imbalances, including aneuploidy, losses, and duplications. Additionally, array CGH can identify chromosomal abnormalities even in the absence of specific diagnostic indications. Aim: This study aims to assess the prevalence of chromosomal abnormalities using the array CGH technique in comparison with karyotyping at Hanoi Obstetrics and Gynecology Hospital. Methods: A total of 399 pregnant women with a gestational age of 17 to 28 weeks underwent amniocentesis at Hanoi Obstetrics and Gynecology Hospital 2020 and 2022. Amniotic fluid samples were simultaneously analyzed using both array CGH and karyotyping techniques. Results: The karyotyping method identified chromosomal abnormalities in 63 out of 399 cases (15.79%), while array CGH detected abnormalities in 98 out of 399 cases (24.56%). Both techniques identified 49 cases of aneuploidy. For larger deletions and duplications, array CGH detected 14 cases compared to 8 identified by karyotyping. In contrast, array CGH identified 16 cases of small deletions and duplications, whereas karyotyping identified only 1 case. Conclusion: Array CGH is a highly accurate diagnostic tool that effectively detects structural chromosomal abnormalities, particularly small deletions and duplications, which may be missed by karyotyping techniques. This underscores the importance of integrating array CGH into prenatal diagnostic protocols for enhanced detection of chromosomal abnormalities.