In the News: DNAJB9- a novel autoantigen staining for Fibrillary GN

A new paradigm shift in diagnosis of Fibrillary GN(FGN) has occurred. This rare form of organized deposit related GN might have a pathology staining marker in the making.

Through the use of laser microdissection assisted liquid chromatography tandem mass spectrometry , The Mayo pathologist  recently discovered a novel proteomic biomarker for FGN: DnaJ homolog subfamily B member 9 (DNAJB9), a member of the molecular chaperone gene family. When looking at specific biopsy samples of FGN vs non FGN cases, strong, homogeneous, smudgy DNAJB9 staining of glomerular deposits was seen in all but 2 cases of FGN in one report published in KI-R.

This test had a 98% sensitivity and > 99% specificity. Immunoelectron microscopy showed localization of DNAJB9 to FGN fibrils but not to amyloid fibrils or immunotactoid glomerulopathy microtubules. (http://www.kireports.org/article/S2468-0249(17)30341-8/pdf)

Another similar manuscript in JASN showed the same finding. 

http://jasn.asnjournals.org/content/early/2017/11/02/ASN.2017050566.abstract( below is the visual abstract)

Looks like we may have a diagnostic test and catch more cases of FGN