Peripheral blood smear shows target cells, basophilic stippling, and nucleated red blood cells. Hemoglobin electrophoresis reveals HbF 90%, HbA2 4%, no HbA. What is the diagnosis?

• A Beta-thalassemia major (Cooley's anemia) — absent or severely reduced beta-chain synthesis ✓
• B Beta-thalassemia intermedia — two mild beta mutations, some HbA present
• C HbE/beta-thalassemia compound heterozygote — HbE and HbF present, reduced HbA
• D Sickle-beta-thalassemia — HbS and HbF elevated, HbA reduced

Explanation

The complete absence of HbA with 90% HbF and elevated HbA2 indicates severely impaired or absent beta-chain synthesis — the hallmark of beta-thalassemia major. In this condition, excess alpha chains precipitate, causing intramedullary hemolysis and peripheral destruction. Beta-thalassemia intermedia has some residual beta-chain production allowing small amounts of HbA. HbE/beta-thal would show HbE on electrophoresis, and sickle-beta-thal would show HbS.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

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