Nat. Genet. 42, 426–429 (2010); published online 11 April 2010; corrected after print 23 March 2011

In the version of this article initially published, incorrect affiliations were published for Lorenzo Beretta and Rafaella Scorza. The correct affiliation for Lorenzo Beretta and Rafaella Scorza is “Referral Center for Systemic Autoimmune Diseases, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico and University of Milan”. The error has been corrected in the HTML and PDF versions of the article.