NKX2-5 and Patent ductus arteriosus: Regarding synonymous variant rs2277923 in NKX2‐5, CT and TT genotypes were presented more frequent in CHD cases (15 ASD, 24 VSD, six PDA, six aortic coarctation and nine Fallot's tetralogy) than control group, as CT genotype was present in 58% and 36% in cases and control respectively.