**Core Concept**
Hereditary hemochromatosis (HH) is a genetic disorder characterized by excessive iron absorption, leading to iron overload and subsequent tissue damage. It is primarily caused by mutations in the HFE gene, which affects the regulation of iron metabolism.

**Why the Correct Answer is Right**
Hereditary hemochromatosis typically presents with increased serum iron levels, elevated serum ferritin, and decreased serum transferrin saturation. The disease is often associated with the C282Y and H63D mutations in the HFE gene. These mutations disrupt the normal function of the HFE protein, leading to increased iron absorption and subsequent tissue damage.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because hereditary hemochromatosis does lead to increased iron absorption, but the primary cause is not a mutation in the transferrin receptor 2 (TFR2) gene. Mutations in the HFE gene are the most common cause.
* **Option B:** This option is incorrect because hereditary hemochromatosis is primarily associated with increased iron absorption, not decreased iron absorption. The disease leads to iron overload, not iron deficiency.
* **Option C:** This option is incorrect because the primary cause of hereditary hemochromatosis is not a mutation in the hepcidin gene, but rather mutations in the HFE gene. Hepcidin plays a role in iron regulation, but it is not the primary cause of the disease.

**Clinical Pearl / High-Yield Fact**
The C282Y mutation in the HFE gene is the most common cause of hereditary hemochromatosis, and it is often associated with increased risk of liver disease, diabetes, and heart failure.

**Correct Answer: A.**