However, TPMT remains the most widely accepted predictor of thiopurine-induced leukopenia to date; current guidelines, including the clinical practice guidelines for AIH by EASL and AASLD, recommend TPMT genotyping prior to the initiation of AZA treatment (Manns et al., 2010; European Association for the Study of the Liver, 2015). The gene discussed is TPMT; the disease is Decreased total leukocyte count.