title: Severe Myelotoxicity Associated with Thiopurine S-Methyltransferase*3A/*3C Polymorphisms in a Patient with Pediatric Leukemia and the Effect of Steroid Therapy.
abstract: Myelosuppression is a serious complication during treatment of acute lymphoblastic leukemia and the duration of myelosuppression is affected by underlying bone marrow failure syndromes and drug pharmacogenetics caused by genetic polymorphisms. Mutations in the thiopurine S-methyltransferase (TPMT) gene causing excessive myelosuppression during 6-mercaptopurine (MP) therapy may cause excessive bone marrow toxicity. We report the case of a 15-year-old girl with T-ALL who developed severe pancytopenia during consolidation and maintenance therapy despite reduction of the dose of MP to 5% of the standard dose. Prednisolone therapy produced a remarkable but transient bone marrow recovery. Analysis of common TPMT polymorphisms revealed TPMT *3A/*3C.
authors.affiliation: Gazi University Faculty of Medicine, Department of Pediatric Hematology, Ankara, Turkey. E-ma-il: draida@yahoo.com.
authors.forename: Burcu Fatma
authors.initials: BF
authors.lastname: Belen
authors.forename: Türkiz
authors.initials: T
authors.lastname: Gürsel
authors.forename: Nalan
authors.initials: N
authors.lastname: Akyürek
authors.forename: Meryem
authors.initials: M
authors.lastname: Albayrak
authors.forename: Zühre
authors.initials: Z
authors.lastname: Kaya
authors.forename: Ülker
authors.initials: Ü
authors.lastname: Koçak