Risk of 22q11.2 deletion in fetuses with right aortic arch and without intracardiac anomalies

Abstract

Objective To assess the risk of 22q11.2 deletion in fetuses with a prenatal diagnosis of right aortic arch without intracardiac anomalies (RAA-no ICA). Methods This was a retrospective study of all fetuses with RAA-no ICA diagnosed prenatally at three referral centers, between 2004 and 2014. A detailed sonographic examination was performed in each case, including visu-alization of the thymus and of the head and neck vessels to identify the presence of an aberrant left subclavian artery (ALSA). Karyotyping and fluorescence in situ hybridiza-tion analysis for diagnosis of 22q11.2 deletion were always offered either prenatally or postnatally. Clinical and echocardiographic examinations were performed in livebirths and a postmortem examination in cases of termination of pregnancy. Results During the study period, 85 fetuses were diagnosed prenatally with RAA-no ICA. Genetic or clinical data were not available for three cases and these were excluded from analysis. 22q11.2 deletion was found in 7/82 cases (8.5% (95% CI, 3.8–17.3%)). The thymus was small or non-visualized in all seven cases and additional abnormal sonographic findings were present in four. Conclusion 22q11.2 deletion is present in a clinically significant proportion of fetuses with a prenatal diagnosis of RAA-no ICA. In such cases, a detailed sonographic examination, with assessment of the thymus in particular, may be useful to further define the level of risk for 22q11.2 deletion. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.