Note: Funding Information: We thank the brave families of both of our patients for their trust and cooperation in this study. We thank Miranda Nijenhuis, Janny Zuiderveen, Gonnie Meijer, Gilles Diercks and Hendri Pas for their assistance in the dermatology laboratory of UMC Groningen. We also acknowledge the wonderful nursing staff of the Giraffe Unit in the Wilhelmina Children’s hospital, UMC Utrecht for their outstanding work. We thank Professors John McGrath (King’s College London, UK), Jakub Tolar (Masonic Children’s Hospital, Univeristy of Minnessota, USA), Christine Bodemer (Necker Hospital, Paris, France) and Dr Anna Martinez (Great Ormond Street Hospital, London, UK) for their role in the international expert advisory panel.