The definitive diagnosis of type I glycogen storage disease GSD is by

(B). The diagnosis of type I GSD is suspected on the basis of clinical presentation and the laboratory findings of hypoglycemia, lactic acidosis, hyperuricemia, and hyperlipidemia. Neutropenia is noted in GSD lb patients, typically before 1 yr of age. Administration of glucagon or epinephrine results in little or no rise in blood glucose level, but the lactate level rises significantly. Before the glucose- 6-phosphatase and glucose-G-phosphate translocase genes were cloned, a definitive diagnosis required a liver biopsy. Gene-based mutation analysis provides a noninvasive way to diagnose most patients with types la and lb disease