Mesangial proliferative glomerulonephritis is a form of glomerulonephritis (inflammation of the kidney glomeruli). The mesangial cells (part of the glomerular capillaries) increase in size and number, giving the glomeruli a lumpy appearance.

The mechanism that triggers the disorder is unknown, but it is believed to be some type of immune response, because inflammation of the glomeruli is associated with deposits of antibodies.

The disorder usually causes nephrotic syndrome (protein loss in the urine and swelling of the body). It may be present as acute, chronic, or rapidly progressive glomerulonephritis, and may progress to chronic kidney failure.

This is a relatively uncommon disorder. The term mesangial proliferative GN is actually a description of the microscopic pattern of this disease.

It may be seen more commonly in lupus patients who develop GN, and in patients who have IgA mediated kidney disease (see IgA nephropathy). It can affect both adults and children. Men may be affected slightly more often than women.