Association between specific dystrophin gene mutations and myocardial fibrosis by cardiovascular magnetic resonance imaging in patients with Duchenne and Becker muscular dystrophy

Background Duchenne (DMD) and Becker (BMD) muscular dystrophies (MD) are allelic X-linked recessive disorders, caused by mutation of the dystrophin gene located at locus Xp21 that consists of 79 exons, characterized by progressive skeletal muscle degeneration and replacement by fibro fatty tissue. Dystrophin is a sarcolemal protein that links the cytoskeleton to the basal lamina and is essential for maintenance of the muscular membrane integrity during muscular contraction. Cardiac involvement is frequent, 70 80% of patients, and often develops clinically silent, without any evident early clinical signs. CMR can identify myocardial fibrosis (MF) and may be useful for detecting the early stages of cardiomyopathy in MD. In a previous study, DNA analyses in 47 pts with DMD revealed significant association between dilated cardiomyopathy (DCM) and specific exons and possible protection against DCM by other exons. The association between specific exons mutation of the dystrophin gene and myocardial fibrosis is until unknown.