A 6-year-old Caucasian boy was referred to the tertiary pediatric treatment center with isolated thrombocytopenia (Hb 113 g/L, Ht 0.31 L/L, RBC 4.1 T/L, Plt 32 G/L, WBC 8.37 G/L upon referral) and superficial skin bleedings suggesting immune thrombocytopenia. Here, GSTM1 is linked to Thrombocytopenia.