KLF13 and ventricular septal defect 1: Other variations in KLF-13 have been linked to congenital heart defects, such as the Glu144*-mutant of KLF13, which cannot trans-activate VEGF-a and ANP gene promoters, which is associated with patent ductus arteriosus, ventricular septal defect, and bicuspid aortic valve [104].