We experienced two female cases of minor glomerular abnormalities with proteinuria disproportionate to the degree of hypoproteinemia. They did not have adequately large amounts of urine protein so as to cause nephrotic syndrome; however, we were unable to determine any cause of hypoproteinemia other than proteinuria. The renal pathology revealed foot process effacement, and hyaline droplet degeneration, suggesting urine protein hyper-reabsorption in the proximal convoluted tubule. Therefore, we thought these cases involved pathophysiological conditions, such as minimal change nephrotic syndrome. In both cases, the hypoproteinemia improved following the administration of oral prednisolone. As in past reports, it is thought that the principal causative factor of hypoalbuminemia in patients with nephrotic syndrome is a catabolic reaction after the serum albumin filtered at the glomerulus is reabsorbed in the proximal tubule. In the present two cases, it is supposed that a large amount of urine protein was filtered in the primitive urine; however, the amount of final urinary protein did not reach the nephrotic range because most of it was reabsorbed in the proximal tubule and reabsorbed in the blood after being disintegrated into amino acids by a catabolic reaction. Or we might simply observe the process before the case 1 got nephrotic syndrome and the healing process of nephrotic syndrome in the case 2.
Keywords: Hyaline droplet degeneration; Hypoproteinemia; Minor glomerular abnormalities; Non-nephrotic proteinuria.