Prenatal microarray analysis in right aortic arch - A retrospective cohort study and review of the literature

Objective:: To examine the risk for clinically significant chromosomal microarray analysis (CMA) findings in fetal right aortic arch (RAA). Methods:: Data from all CMA analyses performed owing to isolated RAA reported to the Israeli Ministry of Health between January 2013 and September 2016 were evaluated retrospectively. Risk for abnormal CMA findings was compared with two control populations, based on both previously described 9272 pregnancies with normal ultrasound, and on a local cohort of 5541 pregnancies undergoing CMA testing owing to maternal request. In addition, Pubmed database search was conducted for original researches examining this issue. Results:: Of 94 CMA analyses performed owing to isolated RAA, six (6.4%) pathogenic findings were detected (47,XX + 21; 45,X; two 22q11.2 microdeletions; 10p15.3 microdeletion and 16p11.2 duplication). Compared with control groups, an isolated RAA yielded a significantly increased relative risk for abnormal CMA results. Literature search yielded two additional retrospective studies describing microarray testing in RAA and encompassing 57 cases. The overall risk for clinically significant CMA findings was 6.62% (10/151). Conclusions:: CMA testing is indicated in cases of prenatal isolated RAA, even in the era of advanced sonographic equipment, routine biochemical screening for Down syndrome and available non-invasive prenatal testing.