The present invention describes the identification of a soluble glomerular permeability factor, anti-Vasorin (or anti-VASN) autoantibodies synthesized by immune system cells, which opens up new perspectives for pathophysiological understanding, monitoring, and therapy of nephrotic syndrome. Clinical applications can include strategies for preventing the action of autoantibodies against said podocyte protein, inhibiting the production of antibodies against this protein, or eliminating these autoantibodies. Although the exact role of anti-VASN autoantibodies and VASN in nephrotic syndrome is still not well understood, the presence of circulating autoantibodies against VASN is highly specific to nephrotic syndrome. Up to now, no anti-VASN autoantibodies have been described in healthy individuals.
Thus, the present invention relates to methods and kits for determining whether a subject has or is at risk of having a nephrotic syndrome associated with anti-VASN auto-antibodies or not.