[Molecular pathology of hepatic glycogen storage disease]

Recent advances of molecular analyses of hepatic glycogen storage diseases have made some progress in understanding of glycogen metabolism. Glucose-6-phosphatase has been shown to comprise at least five different polypeptides, the catalytic subunit, a regulatory Ca2+ binding protein, three transport proteins (glucose-6-phosphate, phosphate/pyrophosphate, glucose). A defect of these protein could cause type I glycogenosis. Only cDNAs of the regulatory Ca2+ binding protein and glucose transport protein were cloned. In type III glycogenosis, using monospecific antibody, correlation of biochemical defects with myopathy and cardiomyopathy was investigated. In type VI glycogenosis, the cDNA of liver phosphorylase was cloned, which will be useful for delineating the molecular defect involved in the disease and family analysis. In type VIII glycogenosis, phosphorylase kinase deficiency, only subunits of muscle type (alpha, beta, gamma, delta) were cloned and clonings of hepatic type subunits were waited. In the near feature, hepatic glycogen storage disease and glycogen metabolism were reevaluated from the points of molecular defects.