Minimal albuminuria

Although there is still debate about its significance, mildly increased excretion (20 to 300mg/L) of albumin, so-called microalbuminuria (more correctly termed minimal albuminuria or paucialhuminuria), appears to be a predictor of future development of clinical renal disease in patients with hypertension or diabetes mellitus. It is important to remember that tubular and postrenal causes of albuminuria may also be present in association with these disorders. 

Minimal change disease is the most common cause of nephrotic syndrome in children, presenting typically with rapid onset of mostly steroid-sensitive nephrotic syndrome, usually with selective proteinuria (albuminuria). Light-microscopic morphology of the kidney is normal and immunofluorescence is negative. Foot process effacement on electron microscopy is the only observed pathology. 

Charge selectivity is probably mediated mainly by the polyanionic glycosamino-glycans present in the glomerular basement membrane (C5, G6). This barrier restricts mostly the movement of relatively small polyanionic proteins (molecular weight 70-150 kDa), mainly albumin. Loss of charge selectivity is believed to be the main cause of albuminuria (selective proteinuria) in minimal change disease (B10). 

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