The Tata Medical Center, Kolkata, reported that 2.2% of 628 patients with ALL had the MLL-F0X04 mutation [14]; our case was a 14-year-old female patient who presented with slight leukopenia (WBC count, 3.85 × 109/L) with a normal platelet count and manual differential counts showing increased neutrophils (72.6%), normal monocytic cells (7.5%), and low eosinophils (0.7%). The gene discussed is KMT2A; the disease is Decreased total leukocyte count.