The use of antisense oligonucleotides (ASOs) was first identified, over twenty years ago, as a method to arrest gene expression levels both in vitro and in vivo where single-stranded DNA or RNA, in antisense configuration, can target a specific sense mRNA. The strategies in the design and chemistry of antisense compounds have become an effective tool in molecular biology basic research, genomics, proteomics, target screening/validation and drug discovery.