Objective:To investigate the clinical significance of prenatal screening and genetic analysis in the diagnosis of fetal aberrant right subclavian artery(ARSA).Methods:The ultrasonographic features of ARSA fetu-ses detected by prenatal ultrasound at the University of Hong Kong-Shenzhen Hospital from October 2017 to March 2022 were retrospectively analyzed.The fetuses were divided into isolated ARSA group and complicated ARSA group.Their genetic analysis results and pregnancy outcome were analyzed.Results:Among 30,260 preg-nant women,185 fetuses were diagnosed with ARSA by prenatal ultrasound screening,with an incidence of 0.6％;5 fetuses(2.6％)were diagnosed by ultrasound in the first trimester,and the remaining were diagnosed by fetal grade Ⅲ structural ultrasound examination at 20～24 weeks' gestation.Among them,158 fetuses(85.4％)had isolated ARSA,and 27(14.6％)had complicated ARSA.Among fetuses with ARSA and other structural abnormal-ities,cardiovascular system accounted for the highest proportion(44.4％),followed by nervous system(22.2％)and urinary system(22.2％).Through genetic analysis,8.3％(4/48)fetuses with isolated ARSA and 40.0％(4/10)fetuses with complicated ARSA were found to have chromosomal numerical or structural abnormalities,with statis-tically significant difference between the two groups(P=0.024).Genetic analysis was completed in 48 isolated ARSA,and the positive rate of pathogenic copy number variants(CNV)was 4.2％(2/48),which was not signifi-cantly different from the pathogenic CNV incidence rate of 0.4％(1/239)in elderly pregnant cases during the same period(P=0.074).The Down syndrome positive likelihood ratio(LR+)for isolated ARSA was 2.5 and the Down syndrome LR+for complicated ARSA was 49.6.Conclusions:Complicated ARSA is often associated with cardiovascular abnormalities and is more likely to develop Down syndrome than isolated ARSA.Although the inci-dence of pCNV in isolated ARSA is slightly higher than the natural incidence,the correlation between pCNV and i-solated ARSA has not been clearly determined by the current sample size.

Objective:To investigate the clinical significance of prenatal screening and genetic analysis in the diagnosis of fetal aberrant right subclavian artery(ARSA).Methods:The ultrasonographic features of ARSA fetu-ses detected by prenatal ultrasound at the University of Hong Kong-Shenzhen Hospital from October 2017 to March 2022 were retrospectively analyzed.The fetuses were divided into isolated ARSA group and complicated ARSA group.Their genetic analysis results and pregnancy outcome were analyzed.Results:Among 30,260 preg-nant women,185 fetuses were diagnosed with ARSA by prenatal ultrasound screening,with an incidence of 0.6％;5 fetuses(2.6％)were diagnosed by ultrasound in the first trimester,and the remaining were diagnosed by fetal grade Ⅲ structural ultrasound examination at 20～24 weeks' gestation.Among them,158 fetuses(85.4％)had isolated ARSA,and 27(14.6％)had complicated ARSA.Among fetuses with ARSA and other structural abnormal-ities,cardiovascular system accounted for the highest proportion(44.4％),followed by nervous system(22.2％)and urinary system(22.2％).Through genetic analysis,8.3％(4/48)fetuses with isolated ARSA and 40.0％(4/10)fetuses with complicated ARSA were found to have chromosomal numerical or structural abnormalities,with statis-tically significant difference between the two groups(P=0.024).Genetic analysis was completed in 48 isolated ARSA,and the positive rate of pathogenic copy number variants(CNV)was 4.2％(2/48),which was not signifi-cantly different from the pathogenic CNV incidence rate of 0.4％(1/239)in elderly pregnant cases during the same period(P=0.074).The Down syndrome positive likelihood ratio(LR+)for isolated ARSA was 2.5 and the Down syndrome LR+for complicated ARSA was 49.6.Conclusions:Complicated ARSA is often associated with cardiovascular abnormalities and is more likely to develop Down syndrome than isolated ARSA.Although the inci-dence of pCNV in isolated ARSA is slightly higher than the natural incidence,the correlation between pCNV and i-solated ARSA has not been clearly determined by the current sample size.