Question

Which of the following disorders describes red cells that acquire a reduced surface area from losing unsupported membrane when defective proteins disrupt vertical interactions between transmembrane proteins and the cytoskeleton?

A. spherocytosis
B. stomatocytosis
C. pyropoikilocytosis
D. acanthocytosis

Answer 1

The disorder characterized by reduced surface area in red cells due to defective membrane support is known as spherocytosis (option a). This condition leads to spherical erythrocytes and hemolytic anemia, differing from the sickled cells caused by sickle cell anemia.

Step-by-step explanation:

The disorder that describes red cells acquiring a reduced surface area from losing unsupported membrane, due to defective proteins disrupting vertical interactions between transmembrane proteins and the cytoskeleton, is known as spherocytosis. This is a condition characterized by the presence of spherical erythrocytes in the bloodstream, as opposed to the normal biconcave disc shape. In spherocytosis, erythrocytes have a reduced lifespan, leading to hemolytic anemia, as the abnormal shape of the cells makes them more susceptible to being destroyed in the spleen.

Sickle cell anemia, delineated as an autosomal recessive disorder, is a genetic disease characterized by the production of abnormal hemoglobin S. This causes red blood cells to assume a sickled shape, especially under low oxygen concentrations, which in turn reduces oxygen delivery to tissues. The sickled cells are stiff and can get stuck in capillaries, leading to painful crises and serious complications like strokes or organ damage. However, this is distinct from spherocytosis as the conditions have different pathological mechanisms and implications.

Answer 2

Spherocytosis is the disorder in which red cells acquire a reduced surface due to defective protein interactions, leading to a sphere shape and causing hemolysis. It is distinct from sickle cell anemia, where abnormal hemoglobin causes crescent-shaped cells, leading to blockages and reduced oxygen delivery.

Step-by-step explanation:

The disorder that describes red cells that acquire a reduced surface area from losing unsupported membrane, due to defective proteins disrupting vertical interactions between transmembrane proteins and the cytoskeleton, is spherocytosis (A). This condition leads to red blood cells becoming more sphere-shaped rather than the normal biconcave disc shape, which in turn makes them more fragile and prone to breaking down, a condition known as hemolysis.

In contrast, sickle cell anemia is a genetic disorder characterized by the production of abnormal hemoglobin S. This abnormal hemoglobin causes red blood cells to assume a sickle (or crescent) shape, especially at low oxygen concentrations. Sickle-shaped cells can become lodged in narrow capillaries, blocking blood flow and reducing oxygen perfusion into the blood. This leads to a variety of complications, including painful crises, organ damage, and increased risk of stroke and infections.