Genetic Testing for Rare and Undiagnosed Diseases

Advances in genetic testing are the most immediate and tangible benefit of the genomic revolution. Never before has it been possible to assay genetic sequence and chromosomal structure so comprehensively and on an industrial scale. The benefits to patients with rare diseases include more rapid and precise diagnosis, improved therapy and outcomes in some cases, and diagnostic closure that terminates what could otherwise have been an interminable odyssey. The challenges in implementation of genetic testing include the cost, ethical issues, gaps in knowledge about mutation pathogenicity and penetrance, and appropriate clinical use. Despite the need to address such challenges, it is foreseeable that essentially all recognizable genetic phenotypes will become routinely diagnosable in the near future. In addition to the intrinsic benefit of diagnosis, the discovery of innumerable novel disease pathways may provide the scientific insights required for the development of new therapies for rare and common diseases alike.