Hereditary nephritis

Alternative names

Alport syndrome; Hematuria - nephropathy - deafness; Hemorrhagic familial nephritis; Hereditary deafness and nephropathy

Definition

Alport syndrome is an inherited disorder (usually X-linked) involving damage to the kidney, blood in the urine, and in some families, loss of hearing. The disorder may also include eye defects.

Causes, incidence, and risk factors

Alport syndrome is very similar to hereditary nephritis. There may be nerve deafness and congenital eye abnormalities associated with Alport syndrome. The cause is a mutation in a gene for collagen. The disorder is uncommon, and most often affects males since the genetic defect is typically found on the X chromosome.

In women, the disorder is usually mild, with minimal or no symptoms. Women can transmit the gene for the disorder to their children, even if the woman has no symptoms of the disorder. In men, the symptoms are more severe and progress faster.

The disorder causes chronic glomerulonephritis with destruction of the glomeruli in the kidneys. Initially, there are no symptoms. Progressive destruction of the glomeruli causes blood in the urine and decreases the effectiveness of the kidney's filtering system.

There is progressive loss of kidney function and accumulation of fluids and wastes in the body, with eventual progression to end-stage renal disease (ESRD) at an early age. ESRD, caused by Alport syndrome, often develops between adolescence and age 40.

Risk factors include having a family history of Alport syndrome, nephritis, end-stage renal disease in male relatives, hearing loss before age 30, bloody urine, glomerulonephritis, and similar disorders.

Symptoms

• Abnormal urine color
  
• Blood in the urine
  
• Loss of hearing, more common in males
  
• Decrease or loss of vision, more common in males
  
• Cough
  
• Ankle, feet, and leg swelling
  
• Swelling, overall
  
• Swelling around the eyes
  

Note: There may be no symptoms in some cases. Symptoms of chronic renal failure or heart failure may be present or may develop.

Signs and tests

Examination is nonspecific, except for blood in the urine. Minute amounts of blood (microscopic hematuria) is present from birth in nearly all affected males. The blood pressure may be elevated. Examination of the eyes may show fundus (posterior inner part of eye) or lens changes, cataracts, or lens protrusion (lenticonus). Examination of the ears shows no structural changes.