PRDM9 and familial dilated cardiomyopathy: Through the interaction of histone methyltransferases and demethylases, histone methylation plays an equally important role in abnormal glycolipid metabolism, cardiomyocyte hypertrophy, extensive myocardial fibrosis, and cardiac diastolic and systolic dysfunction caused by DCM, which will provide new ideas and therapeutic targets for the study and treatment of DCM (62).