Background and aims: Few studies exist on the frequency of thiopurine methyltransferase (TPMT) mutation in patients from Southern Europe. We aimed to evaluate the frequency of TPMT mutation in a homogeneous Sicilian cohort of patients with inflammatory bowel disease (IBD), autoimmune and hematological disorders, the rate of thiopurine-related adverse events, and its association with the TPMT genotype.
Results: Among 105 patients with IBD, 45 with autoimmune disease, and 34 with hematologic diseases, the homozygous TPMT variant genotype was found in one patient only (0.5%), while the heterozygous TPMT genotype was identified in 8 patients (4.3%). In patients with IBD, leukopenia was observed in ten patients: one had the homozygous TPMT genotype, one the heterozygous genotype, and the remaining eight the wild type genotype.
Conclusions: The frequency of TPMT mutation in a Mediterranean area was low. TPMT genotyping is not a sensitive tool for predicting thiopurine-induced leukopenia.
Keywords: 6-Mercaptopurine; Adverse events; Azathioprine; Genetics.
Copyright © 2016 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.