Test Catalog

Test ID: MSFGN    
Fibrillary Glomerulonephritis Confirmation, Mass Spectrometry, Paraffin Tissue

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of fibrillary glomerulonephritis

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

A pathology consultation is typically not required. If the results of this test do not support the clinical findings, a PATHC / Pathology Consultation may be added if appropriate, upon client approval.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Fibrillary glomerulonephritis (FGN) is a rare kidney disease with fibrillary deposits in the glomeruli that contain polyclonal IgG and complement, indicating immune complex deposition. Although usually Congo-red negative, recently cases with weak Congo-red positivity have been observed, making the distinction from amyloid more challenging. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) performed on microdissected glomeruli from patients with FGN demonstrates a unique proteomic profile including the protein DNAJB9 (Mayo Clinic unpublished observations). The presence of DNAJB9 was found to be highly sensitive and specific for FGN, distinguishing it from other glomerular diseases including amyloid, immunotactoid glomerulopathy, and immune complex-mediated proliferative glomerulonephritis. The presence of DNAJB9, in the appropriate clinical and pathological context, can be useful to establish a diagnosis of FGN.

Interpretation Provides information to assist in interpretation of the test results

An interpretation will be provided.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Said SM, Sethi S, Valeri AM, et al: Renal amyloidosis: origin and clinicopathologic correlations of 474 recent cases. Clin J Am Soc Nephrol 2013 Sep;8(9):1515-1523

2. Vrana JA, Gamez JD, Madden BJ, et al: Classification of amyloidosis by laser microdissection and mass spectrometry-based proteomic analysis in clinical biopsy specimens. Blood 2009;114(24):4957-4959

3. Rosenstock JL, Markowitz GS, Valeri AM, et al: Fibrillary and immunotactoid glomerulonephritis: Distinct entities with different clinical and pathologic features. Kidney Int 2003;63:1450-1461

4. Casanova S, Donini U, Zucchelli P, et al: Immunohistochemical distinction between amyloidosis and fibrillar glomerulopathy. Am J Clin Pathol 1992;97:787-795

5. Rosenmann E, Eliakim M: Nephrotic syndrome associated with amyloid-like glomerular deposits. Nephron 1977;18:301-308

6. Nasr SH, Vrana JA, Dasari S, et al: DNAJB9 is a Specific Immunohistochemical Marker for Fibrillary Glomerulonephritis. Kidney Int Rep 2017;3(1):56-64

7. Dasari S, Alexander MP, Vrana JA, et al: DnaJ Heat Shock Protein Family B Member 9 is a Novel Biomarker for Fibrillary GN. J Am Soc Nephrol 2018;(1):51-56