Given that NKX2-5 is a transcription factor with key roles in cardiac development17–20, and because knock out experiments in zebrafish and mouse have demonstrated that NKX2-5 is involved in chamber specification in developing vertebrate hearts21,22, we were interested to further investigate a specific Ebstein’s anomaly-associated variant in the coding sequence of NKX2-5, where a cytosine is converted to an adenine (c.673C > A)16. Here, NKX2-5 is linked to Ebstein anomaly.