Half the dystrophin gene is apparently enough for a mild clinical course: confirmation of its potential use for gene therapy.

The largest in-frame deletion in the dystrophin gene previously reported in a BMD patient encompasses exons 17 to 48, which corresponds to 46% of the coding region. Here we report a larger deletion of exons 13 to 48 in a 37 year-old BMD patient with a mild phenotype. Such deletion, which corresponds to 50% of the coding region is the largest reported so far associated with a benign clinical course. Dystrophin assessment (through immunofluorescence and Western blot) using antibodies against different regions of the dystrophin was concordant with his deletion. The observation of this patient has important implication for gene therapy trials based on minigenes, since it confirms that deletions of up to 66% of the rod domain are compatible with a mild phenotype.