A seven and a half years old child presents with nonblanching rash over the extensor aspect of arm with swelling over knee. Urine analysis shows proteinurea + and hematuris +++. On kidney biopsy, which finding will be most commonly seen?

The presentation (non-blanching rash on extensor surfaces, joint swelling, proteinuria, hematuria) is classic Henoch-Schönlein purpura (IgA vasculitis). The renal manifestation is IgA nephropathy, which shows mesangial IgA deposition on biopsy. Podocyte fusion occurs in minimal change disease, ATN in ischemic/toxic injury, and thickened basement membrane in membranous nephropathy.