Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked muscular dystrophies. The recent isolation of the defective gene in DMD/BMD and the identification of its protein product, dystrophin, have revolutionized our ability to diagnose DMD/BMD and promoted speculation regarding the application of gene therapy. The purpose of this review is to present progress made in this area of research, with particular reference to dystrophin Kobe, which is caused by exon skipping during splicing due to the presence of an intra-exon deletion. On the basis of result of molecular analysis of dystrophin Kobe we propose a novel way of gene therapy for DMD, in which antisense oligonucleotides transform DMD into BMD phenotype by inducing exon skipping.