The cause of hyperuricemia and gout in glucose-6- phosphatase deficiency is
Purine overproduction and hyperuricemia in von Gierke disease (glucose-6-phosphatase deficiency) occurs secondary to enhanced generation of PRPP precursor, i.e. ribose-5-phosphate (a pentose).
In glucose-6-phosphatase deficiency, glucose-6-phosphate cannot be converted to glucose. Accumulated glucose-6-phosphate is then metabolized via HMP shunt, which in turn generates large amounts of ribose-5-phosphate, a precursor of PRPP. The increased synthesis of PRPP then enhances de novo synthesis of purine nucleotides.
More formation of pentose
Decreased availability of glucose to tissues
Increased accumulation of sorbitol
Impaired degradation of free radicals