Atrial Septal Defect 4, also known as asd4, is related to heart septal defect and subvalvular aortic stenosis. An important gene associated with Atrial Septal Defect 4 is TBX20 (T-Box Transcription Factor 20), and among its related pathways/superpathways are Cardiac progenitor differentiation and Heart development. Affiliated tissues include heart and heart-atrium, and related phenotypes are coarctation of aorta and patent foramen ovale