Nat. Genet. 49, 223–237 (2017); published online 19 December 2016; corrected after print 20 April 2017

Following publication of this article, the authors were asked to remove a clinical image and some video footage of one of the affected individuals. Although consent was obtained, in keeping with their ethical consent framework, the authors allow for withdrawal of consent and are carrying out the wishes of the research subjects under their consent process. This amendment has been made in the HTML and PDF versions of the article.