Nephrotic syndrome is a kidney disorder characterized by excretion of too much protein in the urine. It is usually caused by damage to the glomeruli in the kidneys. In nephrotic syndrome, the glomeruli are affected by an inflammation that allows proteins such as albumin, antithrombin or the immunoglobulins to pass through the cell membrane and appear in urine (usually they don’t appear). Nephrotic syndrome causes swelling (edema), usually in feet and ankles, and increases the risk of other health problems.