CACNB2 and Patent ductus arteriosus: Our finding that at least three of the four TFAP2B SNPs, that were associated with persistent PDA, also were associated with the same changes in expression of several of the “DA closure genes” (EPAS1, CACNB2, ECE1, KCNA2, ATP2A3, EDNRA, EDNRB, BMP9, and BMP10) increases the confidence that these may actually represent true positive results.