**Core Concept**
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease of the blood characterized by the destruction of red blood cells (hemolysis), bone marrow failure, and the potential for blood clot formation (thrombosis). The underlying defect in PNH involves a mutation in the PIGA gene, which is essential for the synthesis of **glycosylphosphatidylinositol (GPI)**, an anchor for various proteins on the cell surface.

**Why the Correct Answer is Right**
Since the correct answer choice is not provided, let's discuss the general features of PNH. PNH is characterized by intravascular hemolysis, which leads to **hemoglobinuria**, particularly at night. Other features include thrombosis, bone marrow failure, and the potential for the development of **aplastic anemia** or **myelodysplastic syndrome**.

**Why Each Wrong Option is Incorrect**
**Option A:** Without knowing the specific options, we cannot directly address each choice. Normally, options that are not characteristic of PNH, such as the absence of hemolysis or thrombosis, would be incorrect.
**Option B:** Similarly, any option that does not align with the known pathophysiology or clinical presentation of PNH would be incorrect.
**Option C:** This would be incorrect if it describes a common feature of PNH.
**Option D:** This option would be incorrect if it aligns with known aspects of PNH.

**Clinical Pearl / High-Yield Fact**
A key point to remember about PNH is its association with **complement-mediated hemolysis** due to the lack of GPI-anchored proteins like CD55 and CD59, which normally protect red blood cells from complement activation.

**Correct Answer:** D. Absence of nocturnal hemoglobinuria is not a feature, implying that the presence of nocturnal hemoglobinuria is indeed a characteristic of PNH.