Definition of Membranoproliferative GN I:

Membranoproliferative glomerulonephritis type I is a kidney disorder that results in disrupted kidney function, caused by inflammation and changes in the microscopic structure of kidney cells.

See also: Membranoproliferative GN II

Causes, incidence, and risk factors:

Glomerulonephritis is inflammation of the glomeruli, the inner structures of the kidney that help filter waste and fluids from the blood to form urine.

Membranoproliferative GN I is a form of glomerulonephritis. It is caused by an abnormal immune response. Deposits of antibodies build up in a part of the kidneys called the glomerular basement membrane. This membrane helps filter waste and extra fluid from the blood.

The changes in this membrane lead disrupt the body's ability to filter urine. Protein and fluid leak out of the blood vessels into body tissues, leading to edema. Nitrogen waste products may accumulate in the blood (azotemia) because of poor kidney functioning.

The disorder is often progressive and eventually results in chronic renal failure.

Most cases of membranoproliferative glomerulonephritis are type I. The conditions affects both men and women, mostly people under age 30.