Congenital heart disease (CHD) is the commonest birth defect, affecting approximately 9.4/1 000 live births. Atrial Septal Defect (ASD) is one of the commonest CHD clinical phenotypes, which frequently requires treatment either in childhood or adulthood, and can lead to severe complications such as right heart failure and cardiac arrhythmia. Previous genome-wide association studies (GWAS) have identified a region of chromosome 4p16 (Ch4p16) associated with the risk of ASD. The most strongly associated SNPs (rs870142, rs6824295 and rs16835979) lie within a 38.8-kb region of linkage disequilibrium encompassing only the long noncoding RNA STX18-AS1 (also named LOC100507266) .Associated SNPs are expression quantitative trait locus (eQTLs) for STX18-AS1 in adult ventricular myocardial tissue.