Our search strategy (see Supplementary Material, Supplementary Digital Content 1, http://links.lww.com/CTG/A449 and Figure 1) identified relevant exonic variants in 8 of the 18 pharmacogenes examined (Table 1) including clinically relevant variants applicable to IBD treatment with azathioprine in either TPMT or NUDT15 in 10% of our patients. The gene discussed is TPMT; the disease is inflammatory bowel disease.