High levels of Notch ligand Dll1, were found in the serum of patients with HF (Norum et al., 2016) and, similarly, high levels of Dll1 and periostin, a non-canonical Notch ligand, were found in serum from patients with dilated cardiomyopathy (Norum et al., 2017). The gene discussed is DLL1; the disease is hydrops fetalis.