🏥 USMLE Exam Prep

Sickle cell disease is caused by a mutation in:

A Alpha-globin
B Beta-globin gene substituting valine for glutamic acid at position 6
C Hemoglobin F
D Iron metabolism genes

✓ Correct Answer: Option B

SCD: point mutation in beta-globin gene (Glu→Val at position 6, codon 6). HbS polymerizes when deoxygenated → sickle-shaped RBCs → vaso-occlusive crises, hemolytic anemia.

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