Asymptomatic low molecular weight proteinuria in children.

We reviewed the clinical features in 7 boys with asymptomatic low molecular weight proteinuria. The disease had first been reported by us in 1980. The distinctive features common to all patients were male dominance, asymptomatic proteinuria with a large amount of low molecular weight proteins, normal development and growth, normal renal function tests in childhood, and minimal histological changes in renal biopsy specimens. In 1990, 35 cases have been reported in Japan. Thus, asymptomatic low molecular weight proteinuria is not a rare disease and is one of the causes of isolated proteinuria. Furthermore, this condition is recognized as a new entity.