NUDT15 enzyme dephosphorylates 6-TGN then prevent the incorporation into DNA or RNA (Moriyama et al., 2016) therefore decreasing of the enzymatic activity which observed in NUDT15 variants, particularly NUDT15*3 was leading to thiopurine-induced myelosuppression (Moriyama et al., 2016). This evidence concerns the gene NUDT15 and myelosuppression.