**Question:** Enzyme deficiency in Von Gierke disease is

A. Galactose-1-phosphate uridylyltransferase
B. Glucose-6-phosphatase
C. Glucose-6-phosphate dehydrogenase
D. Pyruvate kinase

**Correct Answer:** B. Glucose-6-phosphatase

**Core Concept:** Von Gierke disease, also known as galactosemia, is a rare genetic disorder caused by deficiency in the enzyme glucose-6-phosphatase (G6PC). This enzyme plays a crucial role in the liver and kidney in breaking down glucose-6-phosphate to glucose-6-phosphate, which is then utilized or stored.

**Why the Correct Answer is Right:**
Enzyme deficiency in Von Gierke disease affects the liver and kidney's ability to break down glucose-6-phosphate, leading to its accumulation in the blood. This accumulation results in the characteristic symptoms of Von Gierke disease, such as liver dysfunction, neurodegeneration, and hyperglycemia.

**Why Each Wrong Option is Incorrect:**
A. Galactose-1-phosphate uridylyltransferase deficiency is responsible for another type of galactosemia, not Von Gierke disease.
C. Glucose-6-phosphate dehydrogenase deficiency is linked to anemia, not Von Gierke disease.
D. Pyruvate kinase deficiency is associated with hemolytic anemia, not Von Gierke disease.

**Clinical Pearl:**
Von Gierke disease serves as a reminder that enzyme deficiencies can cause specific clinical syndromes by impairing the function of specific organs or pathways. In this case, glucose-6-phosphatase deficiency leads to the accumulation of glucose-6-phosphate, causing Von Gierke disease. Understanding the underlying enzyme deficiency is essential for accurate diagnosis and appropriate management of patients with suspected glucose-6-phosphatase deficiency.