A constellation of clinical and laboratory features of renal disease defined by heavy proteinuria with bland urinary sediment, hypoalbuminemia, and peripheral edema. Heavy proteinuria is defined as >3.5 g/24 hours, and hypoalbuminemia as an albumin level <3 g/dL. Patients often have associated hyperlipidemia and thrombotic disease. The incidence of thrombotic events in individuals with nephrotic syndrome is higher in adults (25%) than children (3%). Patients with loss-of-function mutations in sphingosine-1-phosphate lyase may have nephrosis with ichthyosis and adrenal insufficiency.

Nephrotic syndrome is often secondary to systemic disease including diabetes mellitus, systemic lupus erythematosus (SLE), hepatitis B (HBV), hepatitis C (HCV), membranous nephropathy, focal segmental glomerulosclerosis, minimal-change disease, amyloidosis (AA, AL), and other rare etiologies.