EP06.75: Analysis of prenatal ultrasound findings in neonates diagnosed with genetic disorders through next‐generation sequencing

With advances in pregnancy ultrasound and genetic analysis, there has been an increasing frequency of prenatal genetic testing in fetuses diagnosed with congenital anomalies. Conversely, when minor variations or soft markers, instead of major structural anomalies, are found, prenatal genetic testing is not commonly performed. However, for some neonates diagnosed with genetic disorders due to acute complications after birth, prenatal ultrasound may not show major structural anomalies, making prenatal diagnosis challenging. Therefore, we aim to analyse prenatal ultrasound findings that may accompany genetic disorders in neonates diagnosed through Next-Generation Sequencing (NGS). In this retrospective study, we analysed prenatal ultrasound findings and genetic test results of neonates delivered at Severance Hospital between 2018 and 2022. Data was collected on neonates who were born without major congenital anomalies in prenatal ultrasound but underwent NGS due to suspected genetic disorders after birth. The cases where major structural anomalies were identified in prenatal ultrasound were excluded from the analysis. Of the 158 neonates with postnatal NGS, 63 neonates diagnosed with genetic disorders without major structural anomalies in prenatal ultrasound. Meaningful gene mutations(pathogenic, likely pathogenic, and related VOUS) were detected in 38 neonates (60.3%), with 29 of them (76.3%) exhibiting soft markers or abnormalities in fetal size or amniotic fluid observed in prenatal ultrasound. Common prenatal ultrasound findings included intrauterine growth restriction (n = 7), hydramnios (n = 6), and renal pyelectasis (n = 5). Predicting genetic disorders through prenatal ultrasound is challenging. However, when multiple ultrasound findings abnormalities other than major structural anomalies are observed, an assessment for genetic disorders may be considered after birth.