Distrofia muscular de Becker con duplicación en el exón 5del gen DMD

The dystrophinopathies are a group of X-linked genetic disorders. The most important forms of dystrophinopathies are Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). They are caused by mutations of the dystrophin-encoding DMD gene located on the X chromosome at Xp21.1. Among the type of gene DMD mutations reported, deletions and point mutations are the most common, while duplications occur in 10-12% of cases. Although duplications of exon 5 are already reported in the literature, to date there are no cases reported which establish a clear genotype-phenotype correlation. Here we present the case of a patient with Becker muscular dystrophy with a slightly milder phenotype, in whom exon 5 duplication was found. With this case report, we intend to highlight BMD genotype-phenotype correlation by describing BMD clinical features in relation with exon 5 duplication.