NKX2-5 and hereditary disease: Importantly, the team applied their organoid model to investigate a cardiac genetic disease, and demonstrated that NKX2-5-knockout (KO) hESC-derived HFOs showed decreased CM adhesion and hypertrophy with reduced tissue compaction, which were reminiscent of cardiac malformations previously observed in NKX2-5-KO mice [47], highlighting the utility of the HFO system for the in vitro modeling of gene KO phenotypes [46].