Right-sided aortic arch in the age of microarray.

OBJECTIVE: For fetuses with a diagnosis of right aortic arch and normal cardiac anatomy, we aimed to establish the frequency of chromosomal anomaly diagnosed with single nucleotide polymorphism microarray analysis, particularly focusing on microduplications or microdeletions which would have gone undetected by conventional karyotyping and six-probe fish (13,18,21, X,Y, TUPLE).

METHOD: Retrospective study of fetal ultrasounds between 2011 and 2016 in an Australian tertiary referral centre. Outcomes of interest were survival and postnatal surgery for vascular ring.

RESULTS: Thirty patients were identified; 24 were apparently isolated. Chromosomal anomalies were identified in eight fetuses (32%) of 25 who had chromosomal testing. The rate in isolated cases was 11% and 56% in non-isolated cases. The 22q11.2 deletion was identified in three fetuses (12%). Microarray identified copy number variants of potential clinical significance in four additional fetuses (16%). Long continuous stretches of homozygosity were identified in one fetus with cerebellar hypoplasia potentially identifying the loci for recessive mutations. Surgery for vascular ring was performed on seven infants (25%) CONCLUSION: Microarray detected clinically significant chromosomal anomalies in fetuses with right aortic arch that would not be detected with conventional karyotyping. Prenatal counselling should include the chance of postnatal surgery and the importance of long-term follow-up. © 2017 John Wiley & Sons, Ltd.