However, the 13q33.3 deletion of Patient 9 also overlaps a smaller 1.1 Mb deletion with single atrium reported by Yang et al. that did not include either of these two collagen genes.21 Of note, in our cohort, there was another large copy-number gain at 13q33.2-33.3 (patient 8), overlapping five genes (EFNB2, ARGLU1, DAOA-AS1, DAOA and LINC00460), further suggesting the potential importance of this region and ephrin-B2 signalling in CHD.26 Here, EFNB2 is linked to coronary artery disorder.