There are many inconsistencies in the published study results regarding the role of rs2277923 in the NKX2-5 gene, including Iranian [14] Asian [15] Moroccan [16], and Caucasian population [17]; hence, it is needed to analyze all the available published literature that provide us the most definite results for the role of rs2277923 polymorphism in congenital heart diseases. The gene discussed is NKX2-5; the disease is congenital heart disease.