Cardiac troponin T lysine 210 deletion in a family with dilated cardiomyopathy

Background: The gene for cardiac troponin T (TNNT2) is 1 of 7 autosomal disease genes implicated in familial dilated cardiomyopathy (FDC). Identical deletions in exon 13 of TNNT2 have been reported in 2 families with FDC, but little is known about the frequency of this deletion among patients with FDC and idiopathic dilated cardiomyopathy (IDC) and the associated phenotype. Methods and Results: Exon 13 of the cardiac troponin T gene was sequenced in 61 subjects with FDC and 53 subjects with IDC. A 3-base pair deletion (DeltaLys210), identified in 1 family with at least 7 clinically affected fan-Lily members, is reported. Age of disease onset and disease severity varied widely among affected individuals: phenotypic findings included dilated cardiomyopathy, sudden cardiac death, conduction system disease including atrial fibrillation and atrioventricular block, and heart failure. Sudden-onset, rapidly progressive disease was observed in younger individuals. Conclusions: Cardiac troponin T exon 13 lysine deletions can cause FDC of varying severity and are an important but uncommon cause of FDC.