Nat. Genet. 47, 625–631 (2015); published online 4 May 2015; corrected after print 15 July 2015

In the version of this article initially published, the affiliation for Songhun Jang was incorrectly listed as Kim Illinois Sung University, Pyongyang, North Korea. The correct affiliation is Kim Il Sung University, Pyongyang, North Korea. The error has been corrected in the HTML and PDF versions of the article.