In the past decade, there has been a vast increase in the amount of gene sequence information that has the potential to revolutionize the way diseases are both categorized and treated. Old diagnoses, largely anatomical or descriptive in nature, are likely to be superceded by the molecular characterization of the disease. The recognition that certain genes drive key disease processes will also enable the rational design of gene-specific therapeutics. Antisense oligonucleotides represent a technology that should play multiple roles in this process.