**Core Concept**
DiGeorge syndrome is a congenital disorder characterized by thymic hypoplasia, parathyroid gland aplasia or hypoplasia, and cleft palate. The primary immunodeficiency and hypocalcemia associated with DiGeorge syndrome can lead to various complications, including seizures in neonates.

**Why the Correct Answer is Right**
The convulsions in this neonate are likely caused by hypocalcemia, resulting from the parathyroid gland aplasia or hypoplasia. The parathyroid glands are responsible for secreting parathyroid hormone (PTH), which regulates calcium levels in the blood. In the absence or underdevelopment of these glands, PTH levels are inadequate, leading to hypocalcemia. Severe hypocalcemia can cause neuromuscular irritability, manifesting as muscle cramps, tetany, and seizures.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the scenario described. While hypomagnesemia can also cause seizures, the primary issue in DiGeorge syndrome is hypocalcemia.
* **Option B:** Hypoglycemia is not directly related to DiGeorge syndrome or the development of seizures in this context.
* **Option D:** Hypoxia is a general term and not specific to DiGeorge syndrome. It is not the primary cause of seizures in this scenario.

**Clinical Pearl / High-Yield Fact**
DiGeorge syndrome is a classic example of a congenital disorder associated with hypocalcemia and immunodeficiency. It is essential to recognize the clinical features of this syndrome, including hypocalcemia, cleft palate, and cardiac defects, to provide timely diagnosis and management.

**Correct Answer:** C. Hypocalcemia.