en Pediatric Hematology & Oncology Pediatric Hematology & Oncology گزارش مورد Case report Pancytopenia in childhood can be caused by a variety of underlying diseases including hematological and non-hematological entities. Phenylketonuria (PKU) is an inborn error of phenylalanine metabolism. No association between PKU and pancytopenia has ever been reported. We report the first case of PKU revealed by a pancytopenia at presentation. The patient was an infant girl born to healthy non-consanguineous parents with unremarkable family history. A hereditary metabolic disease workup was performed due to the presence of unexplained hematological features and a global developmental delay. Plasma aminoacid profile by thin-layer chromatography showed elevation of phenylalanine and urine organic acid chromatography showed accumulation of metabolites of phenylalanine; whereas, methylmalonic acid or other abnormal organic acids were not found. This is the first case of untreated PKU associated with pancytopenia who improved with low-phenylalanine diet. Phenylketonuria, Pancytopenia, Infant 25 27 http://ijbc.ir/browse.php?a_code=A-10-342-1&slc_lang=en&sid=1 Rim Ben Abdelaziz rimelair@gmail.com 10031947532846004096 10031947532846004096 Yes Department of Pediatrics, La Rabta Hospital, Tunis Tunisia Fathi Mellouli melloulif@yahoo.fr 10031947532846004097 10031947532846004097 No Pediatric Immuno-hematology Unit. Bone Marrow Transplantation Center Tunis,Tunisia Mohamed Tahar Lamouchi lamouchimohamed512@gmail.com 10031947532846004098 10031947532846004098 No Department of Pediatrics, La Rabta Hospital, Tunis, Tunisia Sana Ben Messaoud 10031947532846004102 10031947532846004102 No Laboratory of Research LR12SPO2 Monia Ben Khaled moniabkhaled@yahoo.fr 10031947532846004100 10031947532846004100 No Pediatric Immuno-hematology Unit. Bone Marrow Transplantation Center Tunis,Tunisia Raoudha Doghri raoudha.doghri@gmail.com 10031947532846004099 10031947532846004099 No Department of Pathology, Institut Salah Azaiez, Tunis, Tunisia Hela Boudabous boudaboushela@gmail.com 10031947532846004101 10031947532846004101 No Department of Pediatrics, La Rabta Hospital, Tunis, Tunisia Amel Ben Chehida benchehida_amel@yahoo.fr 10031947532846004103 10031947532846004103 No Department of Pediatrics, La Rabta Hospital, Tunis, Tunisia Hatem Azzouz azzouzhatem@yahoo.fr 10031947532846004104 10031947532846004104 No Department of Pediatrics, La Rabta Hospital, Tunis, Tunisia Mohamed Bejaoui mohamed.bejaoui@rns.tn 10031947532846004105 10031947532846004105 No Pediatric Immuno-hematology Unit. Bone Marrow Transplantation Center Tunis,Tunisia Neji Tebib nejitebib@yahoo.fr 10031947532846004106 10031947532846004106 No Department of Pediatrics, La Rabta Hospital, Tunis, Tunisia