Nat. Med. 23, 250–255 (2017); published online 19 December 2016; corrected after print 18 April 2017

In the version of this article initially published, the Acknowledgements section contained an error: “The WEBs laboratory is supported by the Deutsche Forschungsgemeinschaft grant DFG EXC 1003 (H.S.).” is incorrect. The correct sentence is: “W.E.B.'s laboratory is supported by the Deutsche Forschungsgemeinschaft grant DFG EXC 1003.” The error has been corrected in the HTML and PDF versions of the article.