A new complement factor B mutation associated withcrescentic C3 glomerulopathy; a case report

C3 glomerulopathy is a recently described entity classified as complementassociated glomerular disease.

We report a case of a 48-year-old man referred to the nephrology department for nephrotic syndrome with rapidly progressive kidney failure, acquired partial lipodystrophy and drusen in Bruch’s membrane of the retina. Blood tests showed low C3 and no evidence for autoimmune diseases, monoclonal gammopathy or infection. The renal biopsy revealed a proliferative endocapillary and crescentic glomerulonephritis with glomerular deposits exclusively of C3 and significant interstitial fibrosis. The electronic microscopy was consistent with dense deposit disease. The complement analysis revealed a pathogenic mutation of the complement factor B (CFB) gene not previously described in literature.

The authors report a new mutation of CFB, in a dense deposit disease patient; this finding brings a new insight to the pathogenic pathway of C3 glomerulopathy and possibly to other complement dysregulation associated glomerular diseases. More clinical trials are needed to clarify both the pathogenicity and the optimal treatment for these entities.