This retrospective study was conducted to evaluate changes in the clinical features of MPGN type I in childhood during a 30-year period from 1970 through 1999. Renal biopsies were performed on 2,260 children with glomerulonephritides, among whom were 71 patients with MPGN type-I. Changes in the mode of onset were investigated in patients separated according to the period of onset into two groups by 1974 in which school urinary screening had been widespread. The difference in symptoms after onset was examined between patients with the onset in the 1980s and 1990s under the same circumstances of school urinary screening and of our steroid regimen. Finally, the incidences of this disease in each of the three decades were analyzed. Chance proteinuria and/or hematuria increased (p=0.0107) and acute nephritic syndrome decreased (p=0.0237) in the ratio of the initial symptom on and after 1974. Regarding the clinical presentation after onset, non-nephrotic range proteinuria increased (p=0.0415) and nephrotic syndrome decreased (p=0.0415) in the 1990s, in comparison with the respective rates in the 1980s. The incidence of this disease decreased (p<0.01) in chronological order.
Conclusion: The clinical features of this disease definitely changed over three decades suggesting that the clinical presentation has ameliorated in recent years, regardless of effective palliation of severe symptoms afforded by our steroid regimen.