Final answer:
Glycogen Storage Disease Type 0 (GSD 0) is a metabolic disorder characterized by the liver's inability to convert glucose to glycogen due to the absence of glycogen synthase, leading to difficulties in maintaining normal blood sugar levels.
Step-by-step explanation:
Glycogen Storage Disease Type 0 (GSD 0) is an inherited metabolic disorder where the body is unable to properly store and utilize glycogen, a complex carbohydrate that serves as a major form of energy storage in liver and muscle cells. Unlike Glycogen storage disease type II which involves a build-up of glycogen causing progressive muscle weakness, and other forms involving deficient mobilization of glycogen, GSD 0 is characterized by the absence of glycogen synthase in the liver, an enzyme necessary for converting glucose to glycogen. This results in individuals with GSD 0 having difficulty maintaining normal blood sugar levels, particularly during periods without food (fasting).