G-6-P deficiency occurs in:

Glycogen storage disease type I (GSD I)/ von Gierke's diseaseIt is the most common of the glycogen storage diseases.This genetic disease results from deficiency of the enzyme glucose-6-phosphataseThe deficiency impairs the ability of the liver to produce free glucose from glycogen and from gluconeogenesis.Since these are the two principal metabolic mechanisms by which the liver supplies glucose to the rest of the body during periods of fasting, it causes severe hypoglycemia and results in increased glycogen storage in liver and kidneys.This can lead to enlargement of both.Both organs function normally in childhood, but are susceptible to a variety of problems in adult years.Other metabolic derangements include lactic acidosis and hyperlipidemia.Frequent or continuous feedings of cornstarch or other carbohydrates are the principal treatment.