TGFB3 mutations in the LDS5 (also known as RNHF syndrome) typically cause cleft palate and is also characterized by several cardiovascular malformations, including thoracic and/or abdominal aneurysms, persistent foramen ovale, atrial or ventricular septal defects, atrioventricular block, aortic and mitral valve disease, and familial arrhythmogenic right ventricular dysplasia (ARVD1/C) involving replacement of the ventricular myocardium with fatty and fibrous elements, preferentially in the free wall of the right ventricle [9,12,13,38]. Here, TGFB3 is linked to atrioventricular block.