The frequency observed in this study was 12.4%, which is similar to the frequency of 9.4% in patients with AIH reported by Xiaoli Fan et al.19 Recent studies have found that NUDT15 c.415C>T variants were associated with thiopurine-induced leukopenia, particularly in Asian populations28,32–34. The gene discussed is NUDT15; the disease is autoimmune hepatitis.