Familial and isolated cases of AVCD sometimes show variants in genes encoding for transcriptional factors deeply implicated in cardiogenesis such as TBX20 and Tbx2. Tbx20 is a T-box transcription factor that interacts with Tbx2 to promote EndoMT and proliferation of the AVC tissue. Here, TBX2 is linked to familial atrioventricular septal defect.