The purpose of the present invention is to provide a medicament for high-efficiency skipping of the exon 53 of human dystrophin gene.The present invention provides an oligomer which can make the exon 53 of human dystrophin gene skip.本發明之目的為提供高效率地使人類肌萎縮蛋白基因之第53號外顯子跳讀之藥劑。本發明係提供可使人類肌萎縮蛋白基因之第53號外顯子跳讀之寡聚物。