Introduction: Gene therapy has changed dramatically in the 28 years since the first human gene transfer experiment in 1989. Alipogene tiparvovec, GlyberaR®, a recombinant adeno-associated virus (rAAV) product for lipoprotein lipase deficiency, and Strimvelis®, a lentivirus vector for severe combined immune deficiency are approved in Europe. An rAAV2 product for a congenital form of blindness is currently under review in the United States, likely to be followed by numerous other gene therapies.