IgA nephropathy (IgAN) is the most common type of glomerulonephritis. Its etiology involves an increased production of polymeric immunoglobulin A1 with an abnormal composition of some carbohydrate chains. The reaction of these abnormal forms of IgA1 with specific autoantibodies while circulating immune complexes arise and settle in the renal mesangium with subsequent inflammatory activation of mesangial cells which in up to 50% of cases results in end-stage kidney failure. Pathogenesis involves an interplay of genetic predisposition and environmental effects, mainly of microbial nature. Current therapy is not sufficiently effective and lacks the focus on the cause of the disease, therefore more efficient and specific ways of therapy are being sought to target the individual stages of the pathogenetic process of IgAN development. With the accumulation of knowledge, new questions arise, concerning detailed mechanisms of the pathological processes, as discussed in the text.Key words: autoimmunity - glycosylation of IgA hinge region - IgA nephropathy - immunoglobulin IgA - IgA1 hinge region.