Laboratory investigation revealed leukocytosis (21 × 109/L, reference range [ref] 4–10 × 109/L; 85.3% neutrophils) and elevation of C-reactive protein (CRP) levels (379.0 mg/L, ref. 5.0 mg/L) raised the suspicion of an undetected infection. The gene discussed is CRP; the disease is Increased total leukocyte count.