Left ventricular noncompaction.

Left ventricular noncompaction (LVNC) is a recently defined cardiomyopathy characterized by a pattern of prominent trabecular meshwork and deep intertrabecular recesses, and is thought to be caused by arrest of normal endomyocardial morphogenesis. Although LVNC has been classified as a primary cardiomyopathy of genetic origin, its definition and diagnostic criteria are still being debated. Isolated LVNC was thought to be rare; however, heightened awareness has resulted in an increased detection of the morphological features of LVNC in routine clinical practice, especially in the adult population. Clinical manifestations are highly variable, ranging from no symptoms to disabling congestive heart failure, arrhythmias, and systemic thromboemboli. LVNC, like other forms of inherited cardiomyopathy, is genetically heterogeneous and can be inherited as an autosomal-dominant or X-linked recessive disorder. It has been linked to mutations in several genes, including LIM domain binding protein 3 (ZASP), alpha-dystrobrevin (DTNA), tafazzin (TAZ/G4.5) and those encoding sarcomeric proteins. However, the relatively small contribution of known mutations to the disease, compared with the higher proportion of familial cases suggests that other elusive genes remain to be identified.