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Abstract: SA-PO626

Nephrologists Treating C3 Glomerulopathy Patients Report Highest Clinical Utility by Using Gene Sequencing to Confirm a Diagnosis of C3G in Departure from C3G Consensus Report

Session Information

Category: Genetic Diseases of the Kidney

  • 803 Genetic Epidemiology and Other Genetic Studies of Common Kidney Diseases

Author

  • Stromsness, Bjorn, Machaon Diagnostics, Oakland, California, United States
Background

C3 glomerulopathy (C3G) is a recent renaming of a group of diseases and applies to MPGN Type II and III as well as C3 Glomerulonephritis [2]. In 2013, a C3 glomerulopathy consensus report was published with testing guidelines [1, 3]. We were curious about the degree to which physicians followed these guidelines and their impressions of the tests recommended in that report.

Methods

An anonymous survey titled “C3 glomerulopathy testing: A questionnaire for nephrologists” was sent via email to approximately 4,000 nephrologists.

Results

The C3 glomerulopathy consensus report recommended all suspected C3G patients receive testing for C3 Levels, C4 Levels, C3 Nephritic Factor, CFH Level, Serum paraprotein detection and screening for a CFHR5 mutation. Of the physicians who complete the first detailed section of the survey, 97% reported ordering C3 Levels, 93% had ordered C4 Levels, 69% had ordered CFH Levels and 76% had ordered C3 Nephritic Factor testing.

For the self-identified experts, there were five tests seen as having “High Utility in C3G.” Those tests were C3 Level (67%), C4 Level (67%), C3 Nephritic Factor (67%), CFH Antibody (67%) and Genetic Sequencing (83%).

Conclusion

The clinical value of genetic sequencing (CFH, CFI, CD46, C3, CFB, DGKE, CFHR5), C3 Nephritic Factor and CFH antibody testing appears greater than the consensus report indicated. The importance of serum paraprotein detection (Serum Protein Electrophoresis, or SPEP) and the CFHR5 mutation screen may need to be further demonstrated to the field. Additionally, in a search for performing laboratories, we could not find a test which explicitly targeted the CFHR5 duplication referenced in the consensus report and so physician may not actually be screening for that specific mutation.

Funding

  • Clinical Revenue Support