Investigations revealed anemia with hemoglobin (Hb) 7.7 (11.8–14.6) g/dL, leukocytosis with white blood cell (WBC) count 14.7 (4.0–9.6) × 109 cells/L, reactive thrombocytosis with platelet count 409 (15–360) × 109/L, and C-reactive protein (CRP) of 299.3 (0.0–5.0) mg/L. Here, GSTM1 is linked to thrombocytosis disease.