**Core Concept:** Bater syndrome is a clinical entity characterized by a triad of symptoms including hyperkalemia, hypocalcemia, and hyperphosphatemia. It is caused by a deficiency in the enzyme alkaline phosphatase, which plays a crucial role in calcium and phosphate homeostasis.

**Why the Correct Answer is Right:** Bater syndrome is primarily caused by mutations in the ALPL gene, which encodes the enzyme alkaline phosphatase. This enzyme is essential for maintaining calcium and phosphate homeostasis in the body. When there is a deficiency of alkaline phosphatase, there is an imbalance in calcium and phosphate levels, leading to the characteristic triad of symptoms.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because it does not mention the deficiency of alkaline phosphatase and the resulting imbalance in calcium and phosphate levels.

B. This option is incorrect because it does not focus on the primary cause of Bater syndrome, which is the deficiency of alkaline phosphatase.

C. This option is incorrect as it does not explain the enzyme deficiency and its impact on calcium and phosphate homeostasis.

D. This option is incorrect as it does not address the deficiency of alkaline phosphatase and the resulting imbalance in calcium and phosphate levels.

**Clinical Pearl:** A clinical pearl in this context is to be aware of the association between a deficiency in alkaline phosphatase and the development of Bater syndrome. It is important to consider this syndrome in patients presenting with hyperkalemia, hypocalcemia, and hyperphosphatemia, as early diagnosis and intervention can prevent complications such as cardiac arrhythmias, seizures, and renal failure.

**Correct Answer:** D. Bater syndrome is a result of mutations in the ALPL gene, which encodes alkaline phosphatase enzyme. This enzyme is crucial for maintaining calcium and phosphate homeostasis, and its deficiency leads to the characteristic triad of symptoms observed in Bater syndrome.