Current European guidelines recommend initiation of treatment in all infants aged < 1 year, in children ≥ 1 year of age according to age‐specific immunological thresholds (1–3 years, CD4 count ≤ 1000 cells/μL or CD4% ≤ 25%; 3–5 years, CD4 count ≤ 750 cells/μL or CD4% ≤ 25%; >5 years, CD4 count ≤ 350 cells/μL), and in any child with a World Health Organization (WHO) stage 3/4 or Centers for Disease Control and Prevention (CDC) category B/C event, largely to prevent progression to AIDS and death and to potentially optimize the ultimate CD4 count in adulthood 3. The gene discussed is CD4; the disease is AIDS.