IgA nephropathy: A brief review.

IgA nephropathy is a lifelong disease that is the most common primary glomerulopathy worldwide. It has a complicated and incompletely understood pathogenesis that is theorized as a four 'hit' process involving an improperly produced IgA. While it has a variety of histologic appearances, it is diagnosed by the presence of bright IgA deposits within the mesangium as seen on immunofluorescence and mesangial hypercellularity by light microscopy. This brief review explains the varied histologic features that are important in the diagnosis of IgA nephropathy and the calculation of the MEST-C score that was first introduced by the 2009 Oxford Classification working group.