A peptide nucleic acid derivative of Formula (I) is provided to tightly bind to a splice site withiun a pre-mRNA in a sequence specific manner. Given with excellent cell membrane permeability and strong affinity for RNA, the said peptide nucleic acid derivative induces exon skipping in cells treated with the peptide nucleic acid at sub-femtomolar concentration as "naked" oligonucleotide. The said compound shows therapeutic activity in subjects upon systemic administration even at 1 µg/Kg or less, and therefore is useful to treat a disease or symptom at affordable treatment cost.
