IgA nephropathy (IgAN), also known as Berger's disease (/b??r??e?/) (and variations), or synpharyngitic glomerulonephritis, is a disease of the kidney (or nephropathy) and the immune system; specifically it is a form of glomerulonephritis or an inflammation of the glomeruli of the kidney. Aggressive Berger's disease (a rarer form of the disease) can attack other major organs, such as the liver, skin and heart.

Reference
Wiki: IgA nephropathy