Thalassemias MCQ — NEET PG Practice Question | NEETPGAI
Thalassemias
medium
microscope Pathology
A 7-year-old boy from Tamil Nadu presents with severe pallor, hepatosplenomegaly, and frontal bossing. His parents are consanguineous. Hemoglobin is 6.5 g/dL with microcytic hypochromic indices (MCV 62 fL, MCH 18 pg). Peripheral blood smear shows target cells, nucleated RBCs, and polychromasia. Hemoglobin electrophoresis shows absent HbA, markedly elevated HbF (80%), and trace HbA2 (2%). What is the most likely diagnosis?
A. Beta-thalassemia intermedia
B. Alpha-thalassemia major (Hb Bart's)
C. Beta-thalassemia major
D. Beta-thalassemia trait
Explanation
Diagnosis: Beta-Thalassemia Major
Clinical Presentation
Key Point
Beta-thalassemia major typically presents in infancy or early childhood (6–24 months) with severe hemolytic anemia, hepatosplenomegaly, and skeletal deformities (frontal bossing, maxillary prominence).
This patient's age (7 years), consanguineous parents, and severe anemia with organomegaly are classic for beta-thalassemia major.
Hematologic Findings
Table
Feature
Beta-Thalassemia Major
Hemoglobin
6–8 g/dL (severe)
RBC morphology
Target cells, nucleated RBCs, polychromasia
MCV
Markedly reduced (60–70 fL)
Reticulocyte count
Elevated (compensatory)
High-YieldNEET PG
The combination of absent HbA (0%), markedly elevated HbF (>70%), and trace HbA2 (<3%) is pathognomonic for beta-thalassemia major.
Hemoglobin Electrophoresis Pattern
Key Point
In beta-thalassemia major:
HbA is absent (complete loss of β-globin production from both alleles)
HbF is markedly elevated (80–90%) — γ-globin chains compensate
HbA2 is normal or low (<3%) — α2δ2 is not upregulated
This pattern reflects homozygous or compound heterozygous β-globin mutations with complete absence of normal adult hemoglobin.
Pathophysiology
Clinical Pearl
Beta-thalassemia major results from mutations in both β-globin alleles, leading to:
1.
Severe reduction or absence of β-globin chain synthesis
