Pattern of double glomerulopathy in children.

Occasional case reports have been issued on children with double glomerulopathy, involving either the coexistence of two different glomerulopathies or superimposition of a second glomerulopathy onto a first. A retrospective clinicopathological review of 294 children who had received renal biopsies resulted in 9 (3.1%) being confirmed to have double glomerulopathy. Superimposed glomerulopathy was diagnosed by a second renal biopsy in two cases, and coexistence of two glomerulopathies was confirmed by single biopsy in seven. Original glomerulopathies were those with a chronic course, such as Alport syndrome, IgA nephropathy, relapsing minimal-change nephrotic syndrome, Frasier syndrome, and thin basement membrane nephropathy. The superimposing glomerulopathies were common types in children, such as postinfectious glomerulonephritis, IgA nephropathy, and Henoch-Schönlein nephritis. Thus, the pattern of double glomerulopathy was considered to be due to the chance occurrence of two different glomerulopathies without a common pathogenesis. Acute nephritic symptoms of superimposed glomerulopathies resolved almost completely during follow-up in most cases. Double glomerulopathies are not rare in children and may occur by chance alone in most cases. The possibility of superimposed glomerulopathy should be suspected if the clinical course of a glomerulopathy changes atypically. However, the long-term influence of a superimposed glomerulopathy on renal functional deterioration remains unclear.