Familial IgA nephropathy: a study of renal disease in an Australian aboriginal family.

An Australian Aboriginal family, extending four generations, with a high incidence of renal disease was investigated. Twenty-eight of 114 members screened had hematuria. Of those tested, five had hypertension, four maturity onset diabetes, one a raised serum creatinine concentration, five elevated serum IgA levels and two cortical scarring on intravenous pyelogram. Of the eight members who underwent renal biopsy, five had IgA nephropathy and one had light and electron microscopy evidence of glomerulonephritis, but no IgA was seen on immunofluorescence. One had mild nonspecific changes by light microscopy but no immunofluorescence or electron microscopy was available and the remaining patient had mild changes consistent with hypertension and diabetes. HLA typing, carried out for 27 family members, showed an increased incidence of HLA-B22, B27, B39, and DR1 when compared to Yuendumu Aborigines (B27 and DR1), or Australian Caucasians (B22), or both (B39). This may be due to an association with IgA nephropathy, or a family clustering of antigens. Overall, this study suggests a genetic mechanism in the pathogenesis of IgA nephropathy in some patients and, as there was evidence of renal disease in 25% of those tested, may indicate an underlying high incidence of renal disease in the Aboriginal community.