Additionally, we also found a significant association between TPMT*1/*3C and 6-MP-induced-thrombocytopenia (PLT < 25,000 cell/mm3) during 24 weeks of maintenance therapy when compared with TPMT*1/*1 (OR 4.20; 95% CI: 1.25–14.12; p = 0.014). The gene discussed is TPMT; the disease is Thrombocytopenia.