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Kidney non-tumor

Primary glomerular diseases

C1q nephropathy

Reviewers: Nikhil Sangle, M.D. (see Reviewers page)
Revised: 15 April 2012, last major update April 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.


● Heterogeneous disease (J Am Soc Nephrol 2008;19:2237) first described in 1985 (Am J Kidney Dis 1985;6:103)
● Considered by some an independent disorder, by others a subgroup of primary focal segmental glomerular sclerosis (Clin Exp Nephrol 2009;13:263)
● Rare; causes proteinuria that may progress to end-stage renal failure; rarely presents with gross hematuria (Pediatr Nephrol 2010;25:165)
● Teenagers and young adults, higher incidence among blacks and females
● Presents as nephrotic syndrome, renal insufficiency or hematuria
● Collapsing C1q nephropathy with rapid progression to end-stage renal disease appears to reside in the MYH9-associated disease spectrum (Am J Kidney Dis 2010;55:e21)
● Laboratory testing for lupus and HIV negative, normal complement levels and no evidence of infectious or autoimmune disease


● Clinical course is unpredictable; variable response to corticosteroids or cytotoxic drugs but high rate of renal survival (Pediatr Nephrol 2009;24:77)
● Rituximab may be effective (Clin Exp Nephrol 2011;15:164)

Case reports

● 42 year old man with acute renal failure (Saudi J Kidney Dis Transpl 2011;22:324)

Micro description

● Focal and segmental glomerulosclerosis and minimal change disease patterns most common
● Variable mesangial hypercellularity with increase in mesangial matrix
● Variable segmental glomerulopathy

Micro images

Increase in mesangial cellularity

Various images: H&E, global granular mesangial staining for C1q, EM

Segmental sclerosis and hypercellularity


● Prominent mesangial C1q deposition; also co-deposition of IgG, IgM, IgA and/or C3
● Some cases overlap with IgG nephropathy (Clin Nephrol 2009;72:360)

Electron microscopy description

● Paramesangial electron-dense immune complex deposits

Differential diagnosis

IgA nephropathy: IgA immunofluorescence
Lupus nephritis: may have prominent deposition of C1q, C3 and immunoglobulins; good response to steroids

End of Kidney non-tumor > Primary glomerular diseases > C1q nephropathy

Ref Updated: 4/12/12

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