The etiology of dilated cardiomyopathy remained elusive for a long time that it was defined by the World Health Organization as a “heart muscle disorder of unknown cause”. However, recent research highlighted several genetic mutations that are associated with the condition. Therefore, the more recent definition by the American Heart Association was “a myocardial disorder with mechanical dysfunction, which usually exhibits inappropriate ventricular dilatation, due to a variety of etiologies that frequently are genetic”.

• In the 1980s, the World Health Organization defined cardiomyopathies as “heart muscle diseases of unknown cause”.^[1] This definition reflected the poor understanding of disease etiology.
• Over the past two decades, significant advances have been made in understanding the genetic etiology of dilated cardiomyopathy.
• Mutations in over 80 genes have been associated with this condition.^[2]
• Therefore, more recently, the American Heart Association defined cardiomyopathies as “a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction, which usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilatation, due to a variety of etiologies that frequently are genetic“.^[3]
• Recent studies have revealed the complexity of the genetic basis for dilated cardiomyopathy; however, much remains to be investigated to fully understand the etiology of this condition.