Genetic therapies (a group of techniques developed to correct defective genes) are expected to revolutionize the treatment of rare genetic diseases in the future. Although promising, most of these therapies are currently under development and have a long way to go before their efficacy and safety can be proven. While the potential for these early gene therapy successes to be extrapolated to other conditions and patient populations is exciting, next-generation technologies are dramatically expanding the impact of these medicines on treating human disease.