Antisense Nucleic Acid

An oligonucleotide that expresses a functional human WRN protein against a skip mutation in a 26th or 28th exon of a human WRN gene, or a pharmaceutically acceptable salt thereof, wherein

• one nucleotide is bound to another via a phosphate group and/or modified phosphate group in the oligonucleotide,
• the oligonucleotide contains a modified nucleic acid having at least one modified sugar,
• the oligonucleotide is 10 to 30 mer in nucleotide length, and
• the nucleotide sequence of the oligonucleotide is:
• a nucleotide sequence having a sequence identity of 90% or more and 100% or less with a nucleotide sequence complementary to at least one target region having the same nucleotide length as the oligonucleotide in a nucleotide sequence set forth in SEQ ID NO:
• 1, SEQ ID NO:
• 2, SEQ ID NO:
• 3, SEQ ID NO:
• 4, SEQ ID NO:
• 5, or SEQ ID NO:
• 6;
• a nucleotide sequence complementary to a nucleotide sequence formed by deleting, substituting, inserting, or adding one or several nucleotides in the target region;
• or
• a nucleotide sequence hybridizable with an oligonucleotide having the target region under stringent conditions.