Rapid death of these mice was surprising given that mice with fetal Gata4/6 inactivation by Myh7-Cre (also known as MHCβ-Cre) survived normally through the neonatal period and into adulthood [4], when they died by ~100 days of age from dilated cardiomyopathy. The gene discussed is MYH7; the disease is dilated cardiomyopathy.