Supplementary Material for: Detection Rate of Trisomy 21 in Fetuses with Isolated and Non-Isolated Aberrant Right Subclavian Artery

<b><i>Objective:</i></b> The purpose of this study was to determine the frequency of chromosomal anomalies among the fetuses with isolated and non-isolated aberrant right subclavian artery (ARSA), and to evaluate the sonographic findings associated with ARSA. <b><i>Methods:</i></b> This is a retrospective study conducted during the period between January 2008 and December 2012 at the maternal fetal medicine units of three different referral centers. <b><i>Results:</i></b> Among the 148 cases of ARSA, 98 were isolated and 50 were associated with cardiac anomalies, extracardiac malformations or soft markers. Trisomy 21 was the only chromosomal anomaly with a prevalence of 6.8% (10/148). The corresponding rate was 6.1% (6/98) and 8% (4/50) for isolated and non-isolated ARSA, respectively. Cardiac anomalies, extracardiac findings and soft markers were detected in 5.4% (8), 10.8% (16) and 24.3% (36) of cases, respectively. Among the 10 fetuses with trisomy 21, 6 were isolated, 4 were associated with soft markers, 2 were associated with fetal growth restriction and 1 was associated with hydrops fetalis. Cardiac anomalies were not observed in any of these fetuses. <b><i>Conclusion:</i></b> The prenatal diagnosis of ARSA should prompt meticulous anatomic survey, and karyotype analysis might be offered even in the absence of associated findings.