Mutation in the alpha-cardiac actin gene associated with apical hypertrophic cardiomyopathy, left ventricular non-compaction, and septal defects.

AIMS: The E101K mutation in the alpha-cardiac actin gene (ACTC) has been associated with apical hypertrophic cardiomyopathy (HCM). As prominent trabeculations were described in some carriers, we screened for the E101K mutation in our index patients with HCM, dilated cardiomyopathy (DCM), or left ventricular non-compaction (LVNC).

METHODS AND RESULTS: Clinical, echocardiographic, and genetic screening by restriction fragment length polymorphism of the ACTC E101K mutation in 247 families with HCM, DCM, or LVNC. The mutation was found in five index patients (one with LVNC and four with HCM). Clinical and morphological data were obtained from 94 family members. Forty-six individuals had cardiomyopathy (43 with the mutation and three with no genetic study): 23 fulfilled criteria for LVNC, 22 were diagnosed as apical HCM, and one had been diagnosed as restrictive cardiomyopathy. There had been one heart transplant and one congestive heart failure death in patients with severe diastolic dysfunction, and five premature sudden deaths. The E101K mutation was not found in 48 unaffected relatives. Septal defects (eight atrial and one ventricular) were found in nine mutant carriers from four families, and were absent in relatives without the mutation (P = 0.003).

CONCLUSION: LVNC and HCM may appear as overlapping entities. The ACTC E101K mutation should be considered in the genetic diagnosis of LVNC, apical HCM, and septal defects.