G6PC1 and glycogen storage disease I: Glycogen storage disease type I (GSD I) is an extremely rare and inherited metabolic disorder occurring with an incidence of approximately 1/100,000 to 1/400,000 live births in the general Caucasian population[1,2] and induced by deficiencies of the glucose-6-phosphatase (G6Pase)/glucose-6-phosphate translocase (G6PT) complex.