HbH – MCQ

HbH is seen in which of the following conditions?
A. Deletion of 3 beta genes
B. Deletion of 3 alpha genes
C. Deletion of 4 beta genes
D. Deletion of 4 alpha genes

Correct answer : B. Deletion of 3 alpha genes

• HbH is formed by 4 beta chains (tetramer of beta chains)
• It is seen in alpha thalassemia with deletion of 3 alpha chains
• It is precipitated as Heinz bodies within RBC’s
• Deletion of 4 alpha chains results in formation of Hb Barts (gamma chain tetramer) and is incompatible with life