Cardiac MRI identifies valvular and myocardial disease in a subset of ANO5-related muscular dystrophy patients

Patients with bi-allelic loss-of-function mutations in the gene ANO5 most commonly present with muscular dystrophy. In some studies, patients with ANO5-related dystrophy (ANO5-RD) had evidence of mild cardiac abnormalities; however, cardiac magnetic resonance imaging (MRI) has not been used for myocardial characterization. Ten patients with genetically confirmed ANO5-RD were enrolled in a phenotyping study to better characterize cardiac involvement. Evaluations included medical history, neurological examination and cardiac evaluations (electrocardiogram, echocardiogram and cardiac MRI). All patients were clinically asymptomatic from a cardiac perspective. Muscle MRI was consistent with previous studies of ANO5-RD with increased T1 signal in the posterior and medial compartments of the upper leg and the posterior compartment of the lower leg. Cardiac studies using echocardiography and cardiac MRI revealed dilation of the aortic root and thickening of the aortic valve without significant stenosis in 3/10 patients. There was evidence of abnormal late gadolinium enhancement (LGE) on cardiac MRI in 2/10 patients. In ANO5-RD, the development of cardiac fibrosis, edema or inflammation as demonstrated by LGE has not yet been reported. Cardiac MRI can characterize cardiac tissue and may detect subtle changes before they appear on echocardiography, with potential prognostic implications.

Keywords: ANO5; Anoctamin-5; Cardiac MRI; Cardiac magnetic resonance imaging; Late gadolinium enhancement.