Thalassemias

Which of the following genetic defects characterizes β-thalassemia major?

A 2-year-old child with known β-thalassemia major on regular transfusions presents with progressive hepatomegaly and elevated liver enzymes. The clinician suspects secondary hemochromatosis. Which investigation is most specific for quantifying hepatic iron overload and guiding chelation therapy?

A 6-month-old infant with β-thalassemia intermedia presents with moderate hemolytic anemia and jaundice. The parents request investigation to assess the severity of hemolysis and predict the clinical course. Which investigation is most appropriate for this purpose?

A 3-year-old child with β-thalassemia major on regular transfusions presents with bone pain and facial deformity. Which histopathologic finding in the bone marrow best distinguishes the skeletal changes of thalassemia from those of hereditary spherocytosis?

Which laboratory finding best distinguishes α-thalassemia trait (α-thalassemia 2) from β-thalassemia trait in a 25-year-old Indian woman with microcytic hypochromic anemia?