Von Gierke’s occurs due to deficiency of
Von Gierke's is type I, right? There are different types, like type I to VI, each caused by different enzyme deficiencies. Type I is the most common. The enzyme involved in type I is glucose-6-phosphatase. That enzyme is crucial in the liver and kidneys for breaking down glucose-6-phosphate into glucose, which is then released into the blood. Without this enzyme, the body can't properly release glucose from glycogen, leading to hypoglycemia and other symptoms like hepatomegaly and lactic acidosis.
Now, looking at the options, the correct answer should be glucose-6-phosphatase deficiency. The other options would be other enzymes related to different types of glycogen storage diseases. For example, type V is McArdle's disease, which is due to muscle phosphorylase deficiency. Type II is Pompe's disease, caused by acid alpha-glucosidase deficiency. Type III is Cori's disease, due to debranching enzyme deficiency. So the wrong options are likely other enzymes from different types.
The clinical pearl here is that Von Gierke's disease is the only glycogen storage disease that affects the liver and kidneys, and it's the only one where the enzyme deficiency is in the liver's glucose-6-phosphatase. This leads to the characteristic features like fasting hypoglycemia and lactic acidosis because the body can't release glucose properly. Also, the treatment involves frequent feedings to prevent hypoglycemia and managing other metabolic issues.
So putting it all together, the correct answer is glucose-6-phosphatase deficiency. The other options are for different types of glycogen storage diseases. The key is remembering that each type corresponds to a specific enzyme and organ involvement.
**Core Concept**
Von Gierke’s disease (GSD I) is a glycogen storage disorder caused by **glucose-6-phosphatase deficiency**, impairing gluconeogenesis and glycogenolysis in the liver and kidneys. This enzyme deficiency prevents glucose release from glycogen, leading to hypoglycemia and metabolic acidosis.
**Why the Correct Answer is Right**
Glucose-6-phosphatase catalyzes the final step of gluconeogenesis and glycogenolysis, converting glucose-6-phosphate to free glucose. Its deficiency in GSD I blocks this process, causing **intrahepatocellular accumulation of glycogen and glucose-6-phosphate**. This leads to **lactic acidosis** (due to shunting of glucose-6-phosphate to lactate) and **hyperlipidemia** (via increased ketogenesis). The liver’s inability to release glucose results in fasting hypoglycemia, a hallmark of the disease.
**Why Each Wrong Option is Incorrect**
**Option A:** Phosphofructokinase deficiency causes Tarui’s disease (GSD VII), affecting muscle glycolysis.
**Option B:** Acid alpha-glucosidase deficiency causes Pompe disease (GSD