A patient presents with mild jaundice. On examination he had splenomegaly and his USG abdomen showed gallstones. Peripheral smear showed generalized red cell targeting and occasional cells with angular crystals of hemoglobin C. Formation of hemoglobin C requires substitution of glutamic acid with which of the following amino acid?
High-Yield Explanation
Hemoglobin C is formed by a single amino acid substitution with lysine for glutamine at codon 6. Patients with homozygous hemoglobin C presents with mild hemolytic anemia with splenomegaly, mild jaundice, and pigment (calcium bilirubinate) gallstones. The peripheral blood smear shows generalized red cell targeting and occasional cells with angular crystals of hemoglobin C. Persons heterozygous for hemoglobin C are clinically normal. Ref: Linker C.A., Damon L.E., Damon L.E., Andreadis C. (2013). Chapter 13. Blood Disorders. In M.A. Papadakis, S.J. McPhee, M.W. Rabow (Eds),CURRENT Medical Diagnosis & Treatment 2013.