A 12-year-old girl of Gujarati descent presents with fatigue and dyspnea on exertion. Examination reveals mild jaundice, splenomegaly (3 cm below costal margin), and no hepatomegaly. She has never required blood transfusion. Hemoglobin is 9.5 g/dL, MCV 62 fL, reticulocyte count 8%. Hemoglobin electrophoresis shows HbA 35%, HbA₂ 5.2%, and HbF 60%. What is the most likely diagnosis?

## Diagnosis: Beta-Thalassemia Intermedia ### Clinical Presentation **Key Point:** Beta-thalassemia intermedia is a **non-transfusion-dependent** form of thalassemia with moderate hemolytic anemia, splenomegaly, and a later age of presentation (typically 2–10 years). ### Diagnostic Criteria Comparison | Feature | Beta-Thal Major | Beta-Thal Intermedia | Beta-Thal Trait | Alpha-Thal Trait | | --- | --- | --- | --- | --- | | **Transfusion need** | Regular, from infancy | Occasional or none | None | None | | **HbA** | Absent (0%) | Present (10–30%) | Present (80–95%) | Present (95–98%) | | **HbF** | 70–90% | 10–50% | <1% | <1% | | **HbA₂** | 3–5% | 3–5% | 3.5–5.5% | Normal (2–3%) | | **Hb level** | 6–8 g/dL | 8–10 g/dL | 11–13 g/dL | 12–14 g/dL | | **Reticulocyte count** | 5–10% | 5–8% | <2% | <2% | | **Splenomegaly** | Severe | Mild–moderate | Absent | Absent | | **Age of presentation** | 6–12 months | 2–10 years | Incidental finding | Incidental finding | ### Pathophysiology 1. **Genotype:** Usually β⁺/β⁺ (two hypomorphic alleles) or β⁺/β⁻ (one functional, one non-functional) 2. Reduced but **detectable β-globin production** → HbA present at 10–30% 3. Compensatory increase in HbF and HbA₂ (δ-globin) 4. Moderate hemolysis and ineffective erythropoiesis → mild–moderate anemia 5. Sufficient RBC production to avoid transfusion dependence ### Clinical Pearl **High-Yield:** The **presence of HbA (35%)** with elevated HbF (60%) and elevated HbA₂ (5.2%) in a non-transfused child is the hallmark of beta-thalassemia intermedia. The key distinguishing feature from major is the **presence of functional β-globin chains**. ### Why This Is Not Beta-Thalassemia Major - Major requires **regular transfusions from infancy**; this patient has never been transfused - Major has **absent or trace HbA** (<5%); this patient has 35% HbA - Major presents at 6–12 months; this patient presented at age 12 (later onset) **Mnemonic:** **"Intermedia = In-between"** — intermediate severity, intermediate HbA level (10–30%), intermediate age of presentation (2–10 years). ### Why Alpha-Thalassemia Trait Is Wrong - Alpha-thalassemia trait (2 α-gene deletion) has **normal HbA₂** (2–3%), not elevated (5.2%) - HbF is normal (<1%), not elevated (60%) - Hemoglobin electrophoresis pattern is completely different [cite:Robbins 10e Ch 12]