title: Mesangial glomerulonephropathy with decreased circulating C4 and predominant mesangial C4 deposition in association with one null gene at the C4B locus.
abstract: We report a case of mesangial glomerulonephropathy associated with decreased circulating C4 in a young man with recurrent microscopic hematuria and one null gene at the C4B locus. Mesangial deposits moderately reactive with anti-C4 and weakly reactive with anti-C3 and anti-IgA were found on renal biopsy. No evidence was found to support a diagnosis of IgA nephropathy or any other of the recently described mesangial glomerulonephropathies with immunoglobulin and complement deposition. This case apparently represents a unique, heretofore undescribed variant of mesangial glomerulonephropathy associated with mesangial C4 deposition and C4 hypocomplementemia.
mesh_terms: D000293:Adolescent; D003176:Complement C3 / Q000032:analysis; D003181:Complement C4 / Q000032:analysis* / Q000235:genetics; D015935:Complement C4b; D005455:Fluorescent Antibody Technique; D005920:Glomerular Mesangium / Q000276:immunology* / Q000648:ultrastructure; D005921:Glomerulonephritis / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D006417:Hematuria / Q000209:etiology; D006801:Humans; D005779:Immunodiffusion; D007070:Immunoglobulin A / Q000032:analysis; D008297:Male; D010641:Phenotype
chemical_list: D003176:Complement C3; D003181:Complement C4; D007070:Immunoglobulin A; D015935:Complement C4b