Nat. Biotechnol. 29, 121–128 (2011); published online 7 February 2011; corrected after print 12 April 2011

In the version of the article originally published, Table 1 left off AAV as a section heading. A number of products listed under Adenovirus should have been listed under AAV. Neurologix product NLXP10 was incorrectly listed under the heading of retrovirus, and in phase 2 of development. It should have been listed under the heading AAV, and the phase of development should have read “phase 2 completed.” The errors have been corrected in the HTML and PDF versions of the article.