1Paediatric Digestive Disease Research Centre, Mofid Children’s Hospital, Tehran, Islamic Republic of Iran (Correspondence to A.A. Sayyari: [email protected]). 2Department of Disease Control, Ministry of Health and Medical Education, Tehran, Islamic Republic of Iran. 3Department of Gastroenterology, Henri Mondor Hospital, Paris University XII, Creteil, France. Received: 06/05/03; accepted: 15/...