In the author affiliations on page 1118 of the 9 April 2019 issue, affiliation 5 (Paul Veys and Reem Elfeky), “Institute of Child Health, Great Ormond Street Hospital for Children, London, United Kingdom,” should read, “UCL Great Ormond Street (GOS) Institute of Child Health, London, United Kingdom.” In addition, the following affiliations of Paul Veys were omitted: GOS Hospital for Children NHS Foundation Trust, London, United Kingdom, and NIHR GOS Hospital Biomedical Research Centre, London, United Kingdom. The errors have been corrected in the published article.