What is the primary morphological feature of red blood cells in sickle cell disease?

What is the primary morphological feature of red blood cells in sickle cell disease?

• A. Spherocytes
• B. Target cells
• C. Sickle-shaped erythrocytes due to HbS polymerization
• D. Rouleaux formation

Answer: (C)

Sickle-shaped erythrocytes caused by HbS polymerization when deoxygenated. In sickle cell disease, a mutation in the beta-globin gene produces hemoglobin S. Under low oxygen, HbS molecules polymerize into long fibers that distort and stiffen the red cell, giving a crescent or sickle shape. These rigid cells are less deformable, leading to hemolysis and vaso-occlusion, which are hallmark consequences of the condition. Other morphologies like spherocytes, target cells, or rouleaux reflect different mechanisms or diseases (membrane defects or autoimmune hemolysis for spherocytes; thalassemia or liver-related changes for target cells; increased plasma proteins for rouleaux). The sickled shape directly results from HbS polymerization and explains the clinical features of sickle cell disease.

Sickle-shaped erythrocytes caused by HbS polymerization when deoxygenated. In sickle cell disease, a mutation in the beta-globin gene produces hemoglobin S. Under low oxygen, HbS molecules polymerize into long fibers that distort and stiffen the red cell, giving a crescent or sickle shape. These rigid cells are less deformable, leading to hemolysis and vaso-occlusion, which are hallmark consequences of the condition. Other morphologies like spherocytes, target cells, or rouleaux reflect different mechanisms or diseases (membrane defects or autoimmune hemolysis for spherocytes; thalassemia or liver-related changes for target cells; increased plasma proteins for rouleaux). The sickled shape directly results from HbS polymerization and explains the clinical features of sickle cell disease.