A Comparative Analysis of the Clinical and Pathological Features of IgA Nephropathy and Thin Glomerular Basement Membrane Disease

ABSTRACT

PURPOSE: IgA nephropathy(IgAN) and thin glomerular basement membrane disease(TGBMD) are common glomerular diseases that cause hematuria in childhood. IgAN has characteristics of IgA deposit as the sole or predominantly localized to the mesangium. Recently, it has been reported that thinning of glomerular basement membrane(GBM) is commonly accompanied with precipitation of electron dense deposits in IgAN. We performed this study to examine the frequency of thinning of GBM among children with IgAN and to analysis the correlation between urinary abnormalities and GBM thickness, and furthermore to conduct comparative analysis of the clinical and pathological features of IgAN and TGBMD. METHODS: This study summarizes data collected from Department of Pediatrics, Busan Paik Hospital, Inje Medical College. Data include 51 cases who were diagnosed as IgAN from 1995 to 2000, and 26 cases who were diagnosed as TGBMD from 1990 to 2000 by percutaneous renal biopsy. RESULTS: Males accounted for 29/51(56.9%) patients with IgAN and 8/26(30.8%) of those with TGBMD. The clinical and laboratory features between IgAN and TGBMD were significantly different regarding the incidence of proteinuria(IgAN vs TGBMD 43.1% vs 3.8%, P=0.001), the incidence of co-appearance of proteinuria with hematuria (41.2% vs 3.8%, P=0.001), total amount of protein in 24 hours collected urine (808+/-188.5 mg vs 251+/-00.7 mg, P=0.001) and the incidence of proteinuria more than 1 gm in 24 hours collected urine (23.5% vs 3.8%, P=0.01). On the contrary, there were no significant differences in the levels of serum albumin, creatinine, BUN, and Ccr between two groups. The mean thickness of GBM in patients with IgAN was293.0+/-9.2 nm(139.7-461.9 nm) and 180.9+/-5.8 nm (110.5-229.5 nm) in patients with TGBMD. The mean GBM thickness revealed significantly thinner in TGBMD compared than those with IgAN (P=0.0001). The frequency of thickness being less than 250 nm was 37.4 +/-34.4% in IgAN and 93.0 +/-7.0% in TGBMD (P=0.0001). But there were no correlations between urinary abnormalities and GBM thickness in patients with IgAN. CONCLUSION: The thinning of GBM would be one of the common pathological findings in IgAN. Moreover, there is no significant correlations between urinary abnormalities and GBM thickness in patients with IgAN. However, patients with IgAN tend to have significantly higher possibilities of proteinuria, co-appearance of proteinuria with hematuria and higher total amount of protein in 24 hours collected urine compared those with TGBMD. These differences might be play an important role as progressive prognostic indicators in patients with IgAN.