Final answer:
IgA nephropathy, also known as Berger's disease, is a kidney condition caused by the buildup of IgA in the kidneys. The most common cause is an abnormal immune response.
Step-by-step explanation:
IgA nephropathy, also known as Berger's disease, is a kidney condition caused by the buildup of a protein called IgA in the kidneys. The most common cause of IgA nephropathy is believed to be an abnormal immune response, where the immune system mistakenly produces IgA antibodies that accumulate in the kidneys. This can lead to inflammation and damage to the kidney tissue.