Question
The blood smear of a patient shows the following seen on examination. Most likely the condition involved is?
A. G6PD deficiency.
B. Liver diseases.
C. Lead poisoning.
D. HbC syndromes.
Show Answer
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Correct Answer » D
Explanation
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Arrow pointing in the image is Hemoglobin C crystals
Ans: D. HbC syndromes.
- Hemoglobin C (Hb C) is a structural variant of normal hemoglobin A (Hb A) caused by an amino acid substitution of lysine for glutamic acid at position six of the beta hemoglobin chain.
- This mutated form reduces the normal plasticity of RBCs causing a hemoglobinopathy.Hb C is less soluble than Hb A in red cells.
- Crystal formation may result, leading to increased blood viscosity and cellular rigidity, and shortened red cell survival.
- In those who are heterozygous for the mutation(Hb AC) , about 28–44% of total hemoglobin (Hb) is HbC, and no anemia develops.
- In homozygotes(Hb CC) , nearly all Hb is in the HbC form, resulting in mild hemolytic anemia.
- Target cells, microspherocytes and HbC crystals are found in a blood smear from a homozygous patient.
- In its oxygenated, R state, HbC forms crystals inside red blood cells.
- Hemoglobin C crystals are hexagonal crystals that may be found in individuals with HbC syndromes. The crystals may intracellular or extra-cellular.
- Oxy-HbC crystals also form in red cells of patients with the SC disease, who are doubly heterozygous for both HbS and HbC.
