Objective.-To describe two patients with Fanconi's nephropathy secondary to glycogen storage disease and speculate on the possible etiology. Design.-Convenience sample. Setting.-Tertiary care, referral center. Patients.-Two related children referred for failure to thrive, rickets, and hepatomegaly. Intervention.-Dietary and therapeutic measures for rickets and renal tubular acidosis. Measurements and Results.-The main laboratory findings were fasting hypoglycemia and massive glucosuria, with evidence of multiple renal tubular dysfunction characteristic of the Fanconi syndrome. Liver and kidney biopsy specimens were consistent with glycogen storage disease. Enzymatic assay of liver homogenates revealed marked deficiency of phosphorylase b kinase in one patient and absent activity in the other. Conclusion.-Phosphorylase b kinase deficiency may be causally related to hepatorenal glycogenosis with the Fanconi syndrome. More patients with this syndrome need to be studied before a definitive causal role is implicated.
