Nat. Med.; doi:10.1038/nm.4139; corrected online 28 July 2016

In the version of this article initially published online, the url in the Online database section of the Methods was incorrect. The original version included the url http://www.bbmri.nl/molgenis/500FG. The correct url is http://hfgp.bbmri.nl/. The error has been corrected for the print, PDF and HTML versions of this article.