What is known, however, is that t-tubule remodeling in cardiomyocytes is one of the hallmarks of HF and an indicator of the disease’s progression.17–22 In mammals, the β1AR and β2AR receptor proteins are encoded by the Adrb1 and Adrb2 genes, respectively, both genes having no introns. The gene discussed is ADRB1; the disease is hydrops fetalis.