[1] Guys & St Thomas NHS Fdn Trust, Evelina London Childrens Hosp, Dept Paediat Haematol, London SE1 7EH, England
[2] Imperial Coll Healthcare NHS Trust, Dept Paediat, London, England
[3] Kings Coll London, Sch Med Educ, London, England
[4] St Jude Childrens Res Hosp, 332 N Lauderdale St, Memphis, TN 38105 USA
[5] Univ Illinois, Comprehens Sickle Cell Ctr, Chicago, IL USA
[6] Churchill Hosp, Canc & Haematol Ctr, Oxford, England
[7] Univ Paris 05, Reference Ctr Sickle Cell Dis, Hop Necker Enfants Malad, AP HP, Paris, France
[8] Labex GR Ex, Paris, France
[9] Lagos State Univ, Dept Paediat & Child Hlth, Ikeja, Nigeria
[10] Obafemi Awolowo Univ, Dept Haematol & Immunol, Ife, Nigeria
[11] Univ Connecticut Hlth, Neag Comprehens Canc Ctr, New England Sickle Cell Inst, Farmington, CT USA
[12] Amer Univ Beirut, Dept Pediat Hematol Oncol, Beirut, Lebanon
[13] Univ Calif San Francisco, Benioff Childrens Hosp Oakland, Oakland, CA USA