Provided are tricyclo-
DNA (tc-
DNA) AON and methods employing tc-
DNA AON for modifying splicing events that occur during pre-mRNA
processing. Tricyclo-DNA (tc-DNA) AON are described that may be used to facilitate
exon skipping or to
mask intronic silencer sequences and / or terminal stem-loop sequences during pre-mRNA
processing and to target RNase-mediated destruction of processed mRNA. Tc-DNA AON described herein may be used in methods for the treatment of
Duchenne Muscular Dystrophy by skipping a mutated
exon 23 or
exon 51 within a
dystrophin gene to restore functionality of a
dystrophin protein; in methods for the treatment of
Spinal Muscular Atrophy by masking an intronic silencing sequence and / or a terminal stem-loop sequence within an SMN2
gene to yield modified functional SMN2
protein, including an
amino acid sequence encoded by exon 7, which is capable of at least partially complementing a non-functional SMN1
protein; and in methods for the treatment of Steinert's
Myotonic Dystrophy by targeting the destruction of a mutated DM1 mRNA comprising 3′-terminal CUG repeats.