**Core Concept**
Sickle cell disease (SCD) is a genetic disorder caused by a mutation in the hemoglobin gene, leading to the production of abnormal hemoglobin (HbS). This results in red blood cells that are misshapen and prone to premature destruction, causing various systemic complications.

**Why the Correct Answer is Right**
Sickle cell disease is characterized by several key features, including:
- **Hemolytic anemia**: The premature destruction of red blood cells leads to a shortage of healthy erythrocytes, causing anemia.
- **Sickle-shaped red blood cells**: The abnormal hemoglobin causes red blood cells to become deformed and assume a sickle-like shape.
- **Increased risk of infections**: SCD patients are more susceptible to infections due to functional asplenia and impaired immune function.
- **Vaso-occlusive crises**: The sickled red blood cells can obstruct small blood vessels, leading to pain crises and organ damage.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
It's essential to note that sickle cell disease is a **multisystem disorder** that affects not only the hematologic system but also the cardiovascular, renal, and neurological systems.

**Correct Answer: D.**