Elevated serum and urine sialic acid levels in renal diseases of childhood.

Serum and urine sialic acid levels were measured in various renal diseases of childhood. Serum sialic acid levels were found to be elevated in patients with idiopathic nephrotic syndrome (INS) at onsets and relapses, acute poststreptococcal glomerulonephritis (PSGN) and chronic glomerulonephritis (CGN) found by chance proteinuria and/or hematuria. A large amount of bound sialic acids were excreted in the urine in INS at onsets and relapses, although the serum sialic acid levels were increased. Sephadex G-200 column chromatography revealed three separate peaks with sialoglycoproteins in a patient with INS at onset, but only two peaks in a normal control subject. These results suggest that some sialoglycoproteins are involved in the development of INS, PSGN and CGN.