Alport syndrome

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.

Alternative Names

Causes

Alport syndrome is a form of 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 get worse 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

Exams and Tests

A doctor's exam will likely only reveal blood in the urine. Minute amounts of blood (microscopic hematuria) is present from birth in the urine of nearly all affected males.

The blood pressure may be elevated. Examination of the eyes may show changes in the fundus (posterior inner part of eye) or lens changes, cataracts, or lens protrusion (lenticonus). An ear exam will show no structural changes.

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

Treatment

The goals of treatment include monitoring and controlling progression of the disease and treating the symptoms. The most important task is strict control of high blood pressure.

Treatment of chronic renal failure

Surgical repair of cataracts (cataract extraction), or repair of the anterior lenticonus is possible.

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.

Outlook (Prognosis)

In women, there is usually 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 renal failure are likely by age 50.

Possible Complications

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

When to Contact a Medical Professional

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

Call your health care provider if urine output decreases or stops. This may be a symptom of chronic renal 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.