Idiopathic membranous nephropathy in a patient with congenital C9 deficiency

Abstract

  We report a 5-year-old girl with complete C9 deficiency who developed membranous nephropathy. She presented with proteinuria (0.4-1.0g/day) and hematuria (RBC 15-20/HPF), while neither edema nor hypertension were noted. Laboratory data showed decreased CH 50 value: analysis of each complement component revealed complete deficiency of C9. The titer of ASO and ASK, and blood chemistry data were within normal range. Both anti nuclear antibody and anti DNA antibody were negative. The renal biopsy specimen showed membranous nephropathy (stage I). This is the first report of idiopathic membranous nephropathy in a patient with congenital C9 deficiency.