Characteristic renal biopsy immunofluorescence findings that leads to diagnosis of Berger disease is:

IgA nephropathy (Berger Disease) It is the most common type of glomerulonephritis worldwide. Characterized by the presence of prominent IgA deposits in the mesangial regions and recurrent hematuria. Caused due to deposition of aberrantly glycosylated IgA1 / abnormal IgA containing immune complex in the mesangium. C3 deposits are also found in the glomeruli along with IgA due to activation of alternate complement pathway Immunofluorescence - Mesangial deposition of IgA, often with C3 and properdin. Microscopy shows mesangial wideningandendocapillary proliferation may be seen and on electron microscopy electron dense deposits can be seen in mesangium.