Theoretically, 13% of patients with Duchenne muscular dystrophy may benefit from antisense-mediated slopping of exon 51 to restore the reading frame, which results in the production of a shortened... Show moreTheoretically, 13% of patients with Duchenne muscular dystrophy may benefit from antisense-mediated slopping of exon 51 to restore the reading frame, which results in the production of a shortened dystrophin protein. We give a detailed description with longitudinal follow up of three patients with Becker muscular dystrophy with in-frame deletions in the DMD gene encompassing exon 51. Their internally deleted, but essentially functional, dystrophins are identical to those that are expected as end products in DMD patients treated with the exon 51 skipping therapy. The mild phenotype encourages further development of exon 51 skipping therapy. (C) 2010 Elsevier B.V. All rights reserved. Show less