[1653] Pediatric C1Q Nephropathy Stains for Sox9 and Belongs to Focal-Segmental Glomerulosclerosis (FSGS)

Xu Zeng, Ping L Zhang. Wayne State University, Detroit, MI; William Beaumont Hospital, Royal Oak, MI

Background: C1q nephropathy is a controversial entity with distinctive immunopathologic features: dominant or co-dominant C1q staining in glomerular mesangium. By histology, this group of diseases presents as minimal change disease (MCD) or focal glomerulosclerosis (FSGS). Many authors favor latter but without confirmation due to lack of a reliable molecular marker for FSGS. Increasing evidence indicates that FSGS is due to an irreversible podocyte damage by activation of TGF-mediated apoptosis and initiating fibrogenesis to sclerosis. Sox9 is a transcriptional factor and one of the downstream targets of TGF-. Studies have been showed that Sox9 stains positive in FSGS, but negative in MCD. Thus Sox9 serves as a molecular marker for detecting FSGS. Using immunohistochemitry stain for Sox9 in pediatric C1q nephropathy, the purpose of this study is to confirm that C1q nephropathy is a FSGS but not MCD.
Design: Pediatric patients who had diagnosis of C1q nephropathy with histological features of FSGS/MCD in Children's Hospital of Michigan during 2004-2012 were included in present study. Immunohistochemistry stain for Sox9 was performed in paraffin slide in each case. Sox9 staining (nuclear staining) in podocytes was recorded as positive or negative.
Results: Nine patients had been diagnosed C1q nephropathy in the study time frame and 5 patients had available tissue for performing immunohistochemistry stain for Sox9. Among these, 4 patients had FSGS by histology, 2 of which were “very focal”. One remainder patient had no detectable segmental sclerosis and was considered to be MCD. The Sox9 staining in podocyte was positive in all FSGS patients (4/4, 100%) including those with "very focal" lesions. The Sox9 staining was also positive in MCD patient.

Conclusions: Our data confirms that C1q nephropathy is an entity belongs to FSGS. The positive staining Sox9 in the MCD patient probably relates to sampling issue or an on going evolution of MCD to FSGS. Study in more cases is required to confirm the present findings.
Category: Kidney (does not include tumors)

Monday, March 4, 2013 1:00 PM

Poster Session II # 246, Monday Afternoon


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