NGHIÊN CỨU ĐẶC ĐIỂM SIÊU ÂM VÀ BIẾN THỂ SỐ BẢN SAO TRONG CHẨN ĐOÁN TRƯỚC SINH THAI CÓ BẤT THƯỜNG CẤU TRÚC NÃO

Abstract

Objective: To describe the ultrasonographic characteristics of fetal structural brain anomalies and to analyze associated copy number variations (CNVs) detected in these cases. Methods: A cross-sectional descriptive study was conducted on 207 fetuses diagnosed with brain anomalies via ultrasound and/or magnetic resonance imaging (MRI). All cases underwent amniocentesis for CNV analysis at three major obstetric centers in Vietnam (National Hospital of Obstetrics and Gynecology, Hanoi Medical University Hospital, and Hanoi Obstetrics and Gynecology Hospital) between January 2023 and December 2024. Clinical and genetic data were collected and statistically analyzed using SPSS version 20.0. Results: The mean maternal age was 29.6 ± 5.4 years, and the mean gestational age at diagnosis was 20.3 ± 3.4 weeks. The majority of brain anomalies were identified during the second trimester. Among 207 cases, the most common abnormality was intracranial cystic or mass-like lesions (39.6%), followed by findings requiring differential diagnosis (35.2%), midline  developmental anomalies (9.7%), posterior fossa malformations (9.2%), multiple malformations (3.9%), and cortical malformations (2.4%). Extra-central nervous system anomalies were observed in 35.7% of cases. Pathogenic or potentially pathogenic CNVs were identified in 55 fetuses (26.6%), totaling 65 CNVs, including 45 cases with a single CNV and 10 cases with two CNVs. The detection rate of abnormal CNVs was significantly higher in fetuses with additional anomalies compared to isolated brain anomalies (p < 0.001). Of the CNVs identified, 70.8% were classified as pathogenic, 7.7% as likely pathogenic, 15.4% as variants of uncertain significance (VUS), and 6.1% as benign or likely benign. Conclusion: Fetal brain structural anomalies represent a heterogeneous group of conditions, with cystic/mass lesions and ambiguous findings being the most frequently encountered. CNV analysis plays a pivotal role in the prenatal diagnostic evaluation of brain anomalies, especially in cases accompanied by extracranial malformations. The high proportion (>70%) of pathogenic or likely pathogenic CNVs highlights the clinical relevance of CNV classification for personalized counseling and diagnostic decision-making in prenatal settings.