**Core Concept**
Hyperparathyroidism is a disorder of calcium and phosphate metabolism caused by an overproduction of parathyroid hormone (PTH) by one or more of the parathyroid glands. This leads to increased bone resorption, renal calcium wasting, and increased intestinal calcium absorption.

**Why the Correct Answer is Right**
Hyperparathyroidism is characterized by elevated PTH levels, which stimulate osteoclast activity, leading to bone resorption and increased serum calcium levels. The hypercalcemia can also cause renal impairment, leading to decreased creatinine clearance and increased serum creatinine levels. Additionally, hyperparathyroidism can cause renal stones due to increased calcium excretion.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as hyperparathyroidism is not typically associated with hypocalcemia.
**Option B:** This option is incorrect as hyperparathyroidism can cause renal impairment, leading to decreased creatinine clearance and increased serum creatinine levels.
**Option C:** This option is incorrect as hyperparathyroidism can cause renal stones due to increased calcium excretion.

**Clinical Pearl / High-Yield Fact**
One key feature of hyperparathyroidism is the presence of brown tumors, which are areas of bone resorption that can be palpable and visible on radiographs.

**Correct Answer: A.**