**Question:** All of the following are true of sickle cell thalassemia major, except

A. Increased erythropoiesis
B. Normal hemoglobin levels
C. Absence of beta-globin chains
D. Normal red blood cell membrane composition

**Core Concept:**
Sickle cell thalassemia major is a genetic disorder characterized by abnormal hemoglobin production. It is a form of thalassemia where individuals inherit one normal alpha-globin gene and one beta-globin gene with a mutation (e.g., beta-thalassemia trait). Sickle cell trait is caused by a single abnormal beta-globin gene, while sickle cell anemia is caused by both normal and abnormal beta-globin genes.

**Why the Correct Answer is Right:**
Sickle cell thalassemia major is characterized by increased erythropoiesis, which results in the production of fewer but larger red blood cells. This leads to the characteristic sickle shape and reduced lifespan of these cells. Normal hemoglobin levels are maintained in sickle cell thalassemia major as the abnormal hemoglobin (Hb S) is a minor component of the total hemoglobin.

**Why Each Wrong Option is Incorrect:**
A. Increased erythropoiesis is a feature of sickle cell thalassemia major, not a characteristic of normal hemoglobin levels.
B. Normal hemoglobin levels can be maintained due to the minor presence of abnormal hemoglobin in sickle cell thalassemia major.
C. Absence of beta-globin chains is a characteristic of beta-thalassemia major, not sickle cell thalassemia major. In sickle cell thalassemia major, there is a decrease in alpha-globin chains.
D. Normal red blood cell membrane composition is maintained in sickle cell thalassemia major, as the abnormal hemoglobin does not directly affect the membrane composition.

**Clinical Pearl:**
In sickle cell thalassemia major, the abnormal hemoglobin S (Hb S) is a minor component of the total hemoglobin, usually less than 50%. This genetic disorder is a combination of beta-thalassemia major and the sickle cell trait. The clinical manifestations include severe anemia, frequent infections, and organ damage caused by the sickling of red blood cells. Treatment options include blood transfusion, chelation therapy, and splenectomy.