Declaration of interest
JH Cross has received remuneration to her department as clinical investigator for Vitaflo, GW Pharmaceuticals and Zogenix. She has participated in advisory boards for GlaxoSmithKline, UCB Pharma, Zogenix, GW Pharmaceuticals, Nuticia and Eisai, and as speaker for Shire, Nutricia, Zogenix, GW Pharma and Biomarin, again for which remuneration was made to her department. She holds grants from the European Union, National Institute for Health and Research (NIHR), Action Medical Research, Great Ormond Street Hospital Charity, and SPARKS. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose,