Rare congenital cardiomyopathies characterized by the lack of left ventricular myocardium compaction. The noncompaction results in numerous prominent trabeculations and a loose myocardial meshwork (spongy myocardium) in the LEFT VENTRICLE. Heterogeneous clinical features include diminished systolic function sometimes associated with left ventricular dilation, that presents either neonatally or progressively. Often, the RIGHT VENTRICLE is also affected. CONGESTIVE HEART FAILURE; PULMONARY EMBOLISM; and ventricular ARRHYTHMIA are commonly seen.

Mutations in the tafazzin gene are associated with X-Linked Isolated Noncompaction of the Left Ventricular Myocardium. BARTH SYNDROME is an allelic disorder.

Mutations in the alpha-dystrobrevin gene are associated with Autosomal Dominant type of Noncompaction of the Left Ventricular Myocardium.