IgA nephropathy (NORD)

IgA nephropathy is a disease associated with the kidneys, which are two bean-shaped organs in our body that filter out toxic waste products and excess water from blood and excrete them in the urine. Now, inside each kidney there are clusters of capillaries, that is, tiny blood vessels, called glomeruli, which act like filters of the kidney to let water and the harmful wastes through while keeping important things like red blood cells and proteins in.

IgA nephropathy is caused by an abnormal form of IgA, a type of immunoglobulin, also called an antibody.  Normally, this is  a type of protein that helps the body fight against bacteria and other foreign organisms. When the IgA has an abnormal structure, it can accumulate in the kidneys, causing inflammation and damage.

Now, because of the glomerular injury, red blood cells leak into the urine, causing hematuria. The amount of blood sometimes is enough to cause  reddish or blackish discoloration of the urine. Protein leaking into the urine causes proteinuria and may make the urine appear foamy. Frequently, IgA nephropathy presents in children or young adults as either microscopic or visible hematuria, meaning that it can be seen under a microscope or with the naked eye, and it typically develops during an infection involving the mucosal lining, like infections of the gastrointestinal or respiratory tract. In these sorts of infections, the production of the abnormal IgA antibody gets ramped up, leading to more accumulation in the glomerulus, causing inflammation and injury. With each mucosal infection, the glomeruli undergo more injury, so over time, sometimes decades, individuals may progress to renal failure. Renal failure means decreased kidney function which may cause less formation of urine and building up of excess water in the circulation. This leads to high blood pressure which can damage other organs like the brain and heart. In addition, the protein lost in the urine normally helps water stay in the blood vessels. With less protein in the blood, water starts moving  out of the blood vessels and into the tissues, causing puffiness or edema, mainly in the face and the legs.