**Question:** Sickle Cell Anaemia all are true except

A. Sickle cell anemia is caused by a mutation in the HBB gene.
B. Hemoglobin S is the mutated protein found in red blood cells.
C. The disease primarily affects individuals of African, Mediterranean, or Asian descent.
D. Treatment options include blood transfusions and bone marrow transplantation.

**Correct Answer:** .

**Core Concept:**
Sickle cell anaemia is a genetic disorder that results from a mutation in the HBB gene, specifically a substitution of glutamic acid for valine at position 6 (HbS) of the beta-globin chain. This leads to the formation of abnormal hemoglobin S, which causes red blood cells to become rigid and sickle-shaped when deoxygenated, leading to a range of clinical manifestations.

**Why the Correct Answer is Right:**
The correct answer (D) mentions blood transfusions and bone marrow transplantation as treatment options for sickle cell anaemia. While these treatments are indeed used in some cases, they are not the mainstay of management for this condition.

**Why Each Wrong Option is Incorrect:**
A. While the underlying cause of sickle cell anaemia is indeed a mutation in the HBB gene, the question specifies that all options are true, except for one. Thus, this option is incorrect as it doesn't address a specific treatment option.

B. Although hemoglobin S is the mutated protein found in sickle cell anaemia, this option does not address a specific misconception or incorrect statement about the condition.

C. This option addresses a misconception about the disease's prevalence, stating that it primarily affects individuals of African, Mediterranean, or Asian descent. In reality, sickle cell anaemia can affect individuals from any ethnic background and is not limited to specific populations.

**Clinical Pearl:**
Sickle cell anaemia is a genetic disorder affecting red blood cells, particularly affecting individuals with a homozygous genotype (SS) for the HBB gene mutation. It primarily occurs in individuals of African, Mediterranean, and Asian descent, but can affect individuals from any ethnic background. Treatment focuses on managing symptoms, preventing complications, and providing supportive care. Blood transfusions and bone marrow transplantation are used in specific cases, but not as primary treatments for the disease.

✓ Correct Answer: D. Adults but not children; with sickle cell disease are functionally asplenic, making them susceptible to infections caused by encapsulated bacteria, such as pneumococci.