[Genotype-phenotype discordance in a Duchenne muscular dystrophy patient due to a novel mutation: insights into the shock absorber function of dystrophin]

Abstract

Introduction: Duchenne muscular dystrophy (DMD) is a genomic disorder characterized by progressive muscle wasting and weakness due to the absence or abnormal function of dystrophin; a protein that protects muscle cells from mechanical induced stress during contraction. Mutations in the DMD gene, may lead to different clinical phenotypes, collectively known as dystrophinopathies, of which DMD has the earliest onset and most severe progression.

Case report: We report a novel deletion of exons 24-41, predicted to maintain the reading frame and expected to result in a mild phenotype. Conversely, the patient has a severe DMD phenotype.

Conclusions: Our report supports the hypothesis that disruption of the gamma-actin-binding site located in the central rod domain plays a crucial role in the shock absorber function of dystrophin in muscle cells. Description of pathogenic variants in the DMD gene and the resulting phenotypes has important implications on the designing of molecular therapeutic approaches for DMD.