[1] Med Coll Wisconsin, Childrens Hosp Wisconsin, Childrens Res Inst, Milwaukee, WI 53226 USA
[2] Johns Hopkins Univ, Sch Med, Baltimore, MD USA
[3] Washington Univ, Sch Med, St Louis, MO USA
[4] Univ Missouri, Childrens Mercy Hosp, Kansas City, MO 64108 USA
[5] Northwestern Univ, Childrens Mem Hosp, Chicago, IL 60614 USA
[6] Guys & St Thomas Fdn Trust, London, England
[7] E Carolina Univ, Brody Sch Med, Greenville, NC USA
[8] George Washington Univ, Sch Med, Childrens Natl Med Ctr, Washington, DC USA
[9] Childrens Hosp Vanderbilt, Vanderbilt Meharry Ctr Excellence Sickle Cell Dis, Dept Pediat, Div Hematol Oncol, Nashville, TN USA