The incidence and distribution of biopsy-proven renal diseases in children

The precise distribution pattern of pediatric renal diseases has seldom been reported especially for young children. In order\nto clarify the incidence and distribution of renal diseases in children, 599 renal biopsy specimens obtained from 547 pediatric\npatients (≦15 years old) were analyzed by routine light, electron and immunofluorescence microscopy. Among the total biopsy\ncases, the most common renal disease identified in childhood was IgA glomerulonephritis (IgAGN; 37%). More than 80%\nof patients with IgAGN were discovered by urinary screening at the school, showing asymptomatic proteinuria and/or\nhematuria. The other major renal diseases were minor glomerular abnormality (12.2%), Henoch-Schönlein purpura nephritis\n(HSPN; 10.6%), and thin basement membrane disease (7.1%). One of the major causes of pediatric nephrotic syndrome were\nminimal change nephrotic syndrome (58%), whereas the other causes were IgAGN (11.6%), HSPN (8.9%), membranous\nglomerulonephritis (5.4%), membranoproliferative glomerulonephritis (3.6%). In conclusion, IgAGN was the most common\nrenal disease also in children as in adolescence. From the age of seven years, the incidence of IgA-GN was highest among\nall the pediatric renal diseases during whole childhood period, and the incidence and number of the patients increased as they\ngrow. On the other hand, there are also many cases with non-progressive clinical courses, such as minor glomerular abnormality\nand thin basement membrane disease in children. The renal biopsy following routine urinary screening at the school\nmay be important for the therapeutic and prognostic guidelines of pediatric group of patients with renal diseases.