TBX1 and 22q11.2 deletion syndrome: However, the ligands and receptors of this pathway link to some of the most well-known genes mutated in congenital heart disease, including TBX1 (DiGeorge syndrome), CHD7 (CHARGE syndrome), TBX5 (Holt–Oram syndrome), NKX2.5, and NOTCH1. 6,8–10 Syndromes showing coexistence of all or some of the defects observed in the Robo and Slit mutant mice have been described, including bicuspid aortic valves, septal defects, anomalous inferior caval veins, partial absence of the pericardium, and diaphragmatic hernias7,11–13 but no causative genes have yet been identified.