[1] Aga Khan Univ & Hosp, Dept Paediat & Child Hlth, Karachi, Pakistan
[2] Chinese Univ Hong Kong, Dept Paediat, Hong Kong, Hong Kong, Peoples R China
[3] Univ Malaya, Fac Med, Dept Paediat, Kuala Lumpur, Malaysia
[4] Washington Univ, Sch Med, Dept Pediat, St Louis, MO 63110 USA
[5] Hosp Ninos Benjamin Bloom, Dept Gastroenterol, San Salvador, El Salvador
[6] KK Womens & Childrens Hosp, Dept Paediat, Singapore, Singapore
[7] UCL, Inst Child Hlth, London, England
[8] Stanford Univ, Dept Pediat, Stanford, CA 94305 USA
[9] Royal Free Hosp, Ctr Paediat Gastroenterol, London NW3 2QG, England