Clear evidence of this role is a metabolic disease called type 1a glycogen storage disease (GSD 1a) or von Gierke disease, characterized by Cori and Cori in 1952 [21], that is caused by G6PC1 activity deficit leading to glycogen accumulation and characterized by poor tolerance to fasting, growth retardation, and hepatomegaly as a result of the accumulation of glycogen and fat in the liver. Here, G6PC1 is linked to metabolic disease.