Mixed-pattern immune deposit glomerulonephritis in a child with inherited deficiency of the third component of complement.

The renal histopathology of a 7-year-old Laotian male with inherited deficiency of the third component of complement, recurrent infections, and persistent hematuria and proteinuria is described. The histologic changes are predominantly those of mesangiopathic disease with isolated changes resembling type I membranoproliferative glomerulonephritis and transmembranous glomerulonephritis. IgG, IgA, IgM, C4, and fibrinogen, but not C3, were detected by immunofluorescence in mesangial zones and in segments of capillary walls. A normal distribution of C3b receptors was present along all capillary walls. This report provides additional support for the association of congenital C3 deficiency and immune deposit glomerulonephritis.