1. Hospital Universitario Severo Ochoa and Universidad Internacional Alfonso X El Sabio Madrid Spain
2. Hospital San Roque de Gonnet La Plata, Buenos Aires Argentina
3. Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
4. ASST Centro Traumatologico Ortopedico G. Pini‐CTO Milan Italy
5. National Institute of Musculoskeletal Diseases Budapest Hungary
6. University Hospital of Bicetre, APHP LeKremlin‐Bicêtre France
7. Instituto Nacional de Rehabilitación Luis Guillermo Ibarra and Hospital Juárez de México Ciudad de México Mexico
8. Oslo University Hospital Oslo Norway
9. IRCCS Bambino Gesù Children's Hospital Rome Italy
10. UOC Clinica Pediatrica e Reumatologia, IRCCS Istituto Giannina Gaslini, and University of Genoa Genoa Italy
11. Centre Hospitalier Universitaire de Bicêtre, APHP, National Reference Centre for Auto‐Inflammatory Diseases and Amyloidosis of Inflammatory origin Le Kremlin‐Bicêtre France
12. Children's Hospital of Eastern Ontario Ottawa Ontario Canada
13. Cincinnati Children's Hospital Medical Center and University of Cincinnati Cincinnati Ohio
14. Clinic of Paediatric and Adolescent Rheumatology, St.‐Josef‐Stift Sendenhorst, Northwest German Center for Rheumatology, Sendenhorst, Germany, and Martin‐Luther‐University Halle‐Wittenberg Halle Germany
15. Fondazione Policlinico Universitario Agostino Gemelli IRCCS and Università Cattolica del Sacro Cuore Rome Italy
16. Hospital General Universitario Gregorio Marañón and Universidad Autónoma de Madrid Madrid Spain