Association of IgA nephropathy with steroid-responsive nephrotic syndrome. A report of the Southwest Pediatric Nephrology Study Group.

In a multicenter study of 83 children with IgA nephropathy, we have encountered four patients (three female, one male) who presented with steroid-responsive nephrotic syndrome (NS) 1 to 12 years before the demonstration of IgA nephropathy. Renal biopsies performed within several months of the onset of NS in three of the patients showed changes consistent with minimal change glomerulonephropathy in two and diffuse mesangial hypercellularity in one patient. Immunofluorescence studies performed on two of the biopsies were negative for IgA. Corticosteroid therapy induced remission of NS in all four patients, but this was followed by frequent relapses. IgA nephropathy was diagnosed subsequently by renal biopsies that were performed because of the onset of gross hematuria in three patients and persistent, low-grade proteinuria in the other. Light microscopy studies on these biopsies showed minimal glomerular changes in three and focal proliferative and sclerosing glomerulonephritis in one patient. Subsequent follow-up evaluations have revealed normal serum creatinines and/or glomerular filtration rate (GFR) in all four patients with remission of NS in three and no further episodes of gross hematuria in any patient. These four patients represent either a variant of IgA nephropathy associated with long-standing steroid-responsive NS or development of IgA nephropathy superimposed upon preceding minimal change disease.