Novel mutation in exon 14 of the sarcomere gene MYH7 in familial left ventricular noncompaction with bicuspid aortic valve.

A 49-year-old man with bicuspid aortic valve (BAV) and mild-to-moderate aortic valvular stenosis was referred for investigation of a dilated cardiomyopathy. At the time of presentation, he was physically active, New York Heart Association class I. Physical examination revealed a grade III/ VI harsh crescendo-decrescendo murmur at right upper sternal border radiating to both carotids. His 12-lead ECG revealed a normal sinus rhythm and left ventricular hypertrophy with strain. He was treated with an angiotensin-converting enzyme inhibitor, β-blocker and was routinely followed up for 2 years. Further work up, which included a transthoracic echocar-diogram (Figure 1Ai–1Aiv) and cardiac magnetic resonance imaging (Figure 1Av and 1Avi), established the diagnosis of left ventricular noncompaction (LVNC). Diagnosis of LVNC is primarily based on transthoracic echocardiogram and cardiac magnetic resonance imaging of the 2 layered structure of the myocardium with epicardial compacted and endocar-dial noncompacted zones, with estimation of the ratio of these 2 layers (noncompacted/compacted ≥2 by echo and ≥2.3 by cardiac magnetic resonance) and visualization of the perfused recesses. Evaluation with transthoracic echocardiogram and contrast (Figure 1Ai) and color Doppler (Figure 1Aii) revealed prominent trabeculations, left ventricular apical recesses (sinu-soids) in continuation with the ventricular cavity, reduced LV systolic function (ejection fraction [EF], 30%–35%) with con-comitant LV dilation. His BAV showed severe aortic valvular stenosis (aortic valve area 0.55 cm 2 /m 2 , mean gradient of 70 mm Hg). Because of progressive dyspnea and reduced exercise tolerance coupled with proximal aortic dilatation and reduced cardiac output (EF <30%), he underwent successful aortic valve replacement with a 29-mm freestyle aortic valve and proximal ascending aorta replacement. He is currently asymp-tomatic with excellent exercise tolerance at New York Heart Association class I and EF of 40% to 45%. Discussion LVNC is an important cause of dilated cardiomyopathy caused by the cessation of intrauterine compaction of myocardial fibers during endomyocardial morphogenesis in the first trimester. 1 LVNC is characterized by multiple trabeculations with profound intratrabecular recesses perfused by blood in the ventricular cavity. LVNC is regarded as a genetic disease, which can either affect as an isolated and distinct cardiomy-opathy or be in combination with other forms of congenital heart diseases including BAV. In our proband, genetic studies revealed a novel MYH7:c.1316T>G mutation in exon 14 of the MYH7 gene resulting in a nonconserved single amino acid substitution of arginine for methionine in position 439 (M439R) of the cardiac β-myosin heavy chain head region …