Alport syndrome

Definition

Alport syndrome is an inherited disorder that damages tiny blood vessels in the kidneys.

Alternative Names

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

Causes, incidence, and risk factors

Alport syndrome is an inherited form of kidney inflammation (nephritis). It is caused by a mutation in a gene for a protein in connective tissue, called collagen.

The disorder is uncommon, and most often affects males. Women can transmit the gene for the disorder to their children, even if they have no symptoms.

Risk factors include:

• End-stage kidney disease in male relatives
• Family history of Alport syndrome
• Glomerulonephritis
• Hearing loss before age 30
• Nephritis

Symptoms

The disorder damages the tiny blood vessels in the kidneys, called glomeruli, that filter wastes.

At first, there are no symptoms. However, progressive destruction of the glomeruli leads to blood in the urine and may decrease the effectiveness of the kidney's filtering system. There is a progressive loss of kidney function and a build-up of fluids and waste products in the body.

In women, the disorder is usually mild, with minimal or no symptoms. In men, the symptoms are more severe and get worse faster.

Symptoms include:

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

The condition can progress to end-stage renal disease (ESRD) at an early age (between adolescence and age 40).

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

Signs and tests

• Changes to the eye, including the fundus (posterior inner part of eye), lens, cataracts, or lens protrusion (lenticonus)
• Elevated blood pressure
• Tiny amounts of blood in the urine (microscopic hematuria)

The following tests may be done:

• Urinalysis shows blood, protein, and other abnormalities.
• BUN and creatinine are elevated.
• Red blood cell count, hematocrit may decrease.
• Audiometry may show nerve deafness.
• Renal biopsy shows chronic glomerulonephritis with changes typical of Alport syndrome.

Treatment

The goals of treatment include monitoring and controlling progression of the disease and treating the symptoms. Most important is to strictly control blood pressure.

Treatment of chronic kidney failure may become necessary. This can include dietary modifications, fluid restriction, and other treatments. Ultimately, chronic kidney failure progresses to end-stage kidney disease, requiring dialysis or transplantation.

Surgical repair of cataracts (cataract extraction), or repair of the anterior lenticonus in the eye may be needed.

Loss of hearing is likely to be permanent. Counseling and education to increase coping skills can be helpful. Learning new skills such as lip reading or sign language may be of some benefit. Hearing aids are helpful. Young men with Alport syndrome should use hearing protection in noisy environments.

Genetic counseling may be recommended because of the inherited pattern of the disorder.

Expectations (prognosis)

Women usually have a normal life span with no signs of the disease except for blood in the urine. Rarely, women will have high blood pressure, swelling, and nerve deafness as a complication of pregnancy.

In men, deafness, visual difficulties, and kidney failure are likely by age 50.

Complications

• Chronic renal failure
• Decrease or loss of vision
• End-stage renal disease
• Permanent deafness

Calling your health care provider

Call for an appointment with your health care provider if your symptoms suggest Alport syndrome, or if you have a family history of Alport syndrome and you are planning to have children.

Call your health care provider if your urine output decreases or stops or if you see blood in your urine. This may be a symptom of chronic kidney failure.

Prevention

This uncommon disorder is inherited. Awareness of risk factors, such as a family history of the disorder, may allow the condition to be detected early.

References

Appel GB. Glomerular disorders and nephrotic syndromes. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 122.