Exon skipping therapy by antisense oligonucleotide is a promising approach to Duchenne muscular dystrophy (DMD). We have reported the proof-of-concept studies using morpholino on mice or dog DMD model and on patient derived cells. Based on these results, we had promoted collaborative research with a Japanese pharmaceutical company and encouraged development of DMD gene exon 53 skipping drug, then finally started an investigator-initiated clinical trial from 2013. Furthermore, we are addressing exploratory researches to expand the possibility of AON; such as, an application of AON to Fukuyama congenital muscular dystrophy, and an elucidation of AON uptake mechanism.