Unreliability of platelet glucose-6-phosphatase for the diagnosis of glycogen storage disease type Ia.

The diagnosis of glycogen storage disease type Ia currently uses enzyme analysis of liver tissue. This requires liver biopsy in the at-risk neonate or fetus. Conflicting reports have appeared in the literature on the use of peripheral platelet glucose-6-phosphatase activity for the diagnosis of this disorder. We have applied a sensitive radiometric assay system to the measurement of glucose-6-phosphatase activity in peripheral platelets. Two families with affected members were analysed, revealing no differences in glucose-6-phosphatase activity as compared with control values. Platelet measurement of glucose-6-phosphatase does not appear to be useful for the diagnosis of glycogen storage disease type Ia.