[1] Univ Cape Town, Red Cross War Mem Childrens Hosp, Dept Paediat & Child Hlth, Cape Town, South Africa
[2] Stellenbosch Univ, Tygerberg Hosp, Dept Paediat & Child Hlth, Cape Town, South Africa
[3] Univ Cape Town, Dept Pediat & Child Hlth, Res Ctr Adolescent & Child Hlth REACH, ZA-7700 Cape Town, South Africa
[4] Univ Cape Town, Dept Pediat & Child Hlth, MRC, Unit Child & Adolescent Hlth, ZA-7700 Cape Town, South Africa
[5] George Washington Univ, Childrens Natl Med Ctr, Ctr Genet Med Res, Washington, DC USA
[6] George Washington Univ, Childrens Natl Med Ctr, Div Nephrol, Washington, DC USA
[7] George Washington Univ, Dept Pediat, Washington, DC 20052 USA
[8] Univ Cape Town, Sch Publ Hlth & Family Med, Div Epidemiol & Biostat, Cape Town, South Africa
[9] Sch Publ Hlth & Family Med, Ctr Infect Dis Epidemiol & Res, Cape Town, South Africa
[10] Univ Cape Town, MRC, Unit Child & Adolescent Hlth, Cape Town, South Africa