Elevated serum concentrations of DNAJB9 in fibrillary glomerulonephritis: another step toward understanding a progressive disease.

DnaJ homolog subfamily B member 9 (DNAJB9) is a sensitive and specific marker of fibrillary glomerulonephritis (FGN) in kidney biopsies. In this issue, Nasr and Dasari et al. demonstrate significantly elevated concentrations of DNAJB9 in serum from patients with FGN. This advances our understanding of DNAJB9 as a biomarker in FGN and reframes questions about pathogenesis and potential clinical applications of DNAJB9 serum testing.