SIRT1 and dilated cardiomyopathy: Interestingly, mice displaying a non-tissue specific complete (homozygous) or partial (heterozygous) constitutive SIRT1 deficiency exhibit a dilated cardiomyopathy at 5 months of age which is not associated with cardiomyocyte hypertrophy [26]; the cross-sectional area of cardiomyocytes was even reduced in this model.