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.
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.