TNNT1 and familial dilated cardiomyopathy: The deletion of lysine at amino acid 210 (del210K) in TnT can affect both young and older patients.22 This deletion mutation was engineered in a knock-in mouse where it resulted in DCM with reduced survival.65 Cardiac muscle fibers showed a decreased Ca2+ sensitivity for force generation, with markedly enlarged hearts leading to heart failure and frequently sudden death.