NKX2-5 and ventricular septal defect: According to the data reported in previous studies, genes involved in the circulatory system and cardiac development such as, GATA4, NKX2.5, TBX5, VEGF, MTRR, MTHFR, ISL1, NFATC1 and CITED2 play crucial roles in the etiology of VSD [26].