has material basis in germline mutation in HAND2 congenital heart disease cardiogenetic disease HAND2 related congenital heart defect https://github.com/monarch-initiative/mondo/issues/6667 HAND2 related congenital heart defect DHAND2 HLH transcription factor HAND2 Thing2 MONDO:0800476 DHAND A heart disease that is present at birth caused by a variation in th HAND2 gene. Representative examples include tetralogy of fallot and ventricular septal defect. Hed HAND2-related congenital heart defect bHLHa26