Consequently, an analysis of the TPMT genotypes before starting treatment may be useful for predicting myelosuppression and other AEs in IBD patients with TPMT polymorphisms, in addition to measurements of the enzyme activity and concentration of 6-TGNs, to ensure the safe use of AZA/6-MP [3,8,13,16,24]. The gene discussed is TPMT; the disease is inflammatory bowel disease.