Interestingly, in NipblFLEX/+;cTnt-Cre hearts, the incidence of ASDs was also very low: of 19 hearts analyzed, only 1 displayed an ASD (~5%), which is significantly different from NipblFLEX/+, and statistically indistinguishable from wildtype (S1 Data). Here, TNNT2 is linked to atrial septal defect.