It is also essential for cardiac septation.[41, 42, 43] TBX5 inactivation causes cardiac septal defects in animal models.[41, 42, 44] In humans, mutations in TBX5 are associated with CHD, including ASD and VSD.[45, 46, 47, 48, 49] Based on these findings, the appearance of high leucine level‐correlated CHD phenotypes in the present study could be explained by the inactivation of TBX5. The gene discussed is TBX5; the disease is atrial septal defect.