Alport syndrome

Definition

Alport syndrome is a hereditary disease of the kidneys that primarily affects men, causing blood in the urine, hearing loss, and eye problems. Eventually, kidney dialysis or transplant may be necessary.

Demographics

Alport syndrome affects about one in 5,000 Americans, striking men more often and more severely than women. There are several varieties of the syndrome, some occurring in childhood and others not causing symptoms until men reach their 20s or 30s.


Description

All varieties of Alport syndrome are characterized by kidney disease that usually progresses to chronic kidney failure and by uremia (the presence of excessive amounts of urea and other waste products in the blood).



Causes

Alport syndrome, in most cases, is caused by a defect in one or more genes located on the X chromosome. It is usually inherited from the mother, who is a normal carrier. However, in up to 20% of cases there is no family history of the disorder. In these cases, there appears to be a spontaneous genetic mutation causing Alport syndrome.

Blood in the urine (hematuria) is a hallmark of Alport syndrome. Other symptoms that may appear in varying combinations include:

  • protein in the urine (proteinuria)
  • sensorineural hearing loss
  • eye problems such as nystagmus (involuntary, rhythmic eye movements), cataracts, or cornea problems
  • skin problems
  • platelet disorders
  • abnormal white blood cells
  • smooth muscle tumors

Not all patients with Alport syndrome have hearing problems. In general, those with normal hearing have less severe cases of Alport syndrome.

Diagnosis

Alport syndrome is diagnosed with a medical evaluation and family history, together with a kidney biopsy that can detect changes in the kidney typical of the condition. Urinalysis may reveal blood or protein in the urine.

Tests

Blood tests are performed to evaluate platelet levels. Low platelet levels are another indication of Alport syndrome. Tests for the Alport gene are now available. Although testing is fairly expensive, it is covered by many types of health insurance. DNA tests can diagnose affected children even before birth, and genetic linkage tests tracing all family members at risk for Alport syndrome are available.

Treatment

There is no specific treatment that can cure Alport syndrome. Instead, care is aimed at easing the problems related to kidney failure, such as the presence of too many waste products in the blood (uremia).

To control kidney inflammation (nephritis), patients should:

  • restrict fluids
  • control high blood pressure
  • manage pulmonary edema
  • control high blood levels of potassium

Rarely patients with Alport syndrome may develop nephrotic syndrome, a group of symptoms including too much protein in the urine, low albumin levels, and swelling. To ease these symptoms, patients should:

  • drink less
  • eat a salt-free diet
  • use diuretics
  • have albumin transfusions

The treatment for chronic kidney failure is dialysis or a kidney transplant.

Prognosis

Women with this condition can lead a normal life, although they may have slight hearing loss. An affected woman may notice blood in her urine only when under stress or pregnant.

Men generally have a much more serious problem with the disease. Most will experience kidney disease in their 20s or 30s, which may eventually require dialysis or transplantation, and many develop significant hearing loss. Men with Alport syndrome often die of complications by middle age.

Prevention

Alport syndrome is a genetic disease and prevention efforts are aimed at providing affected individuals and their families with information concerning the genetic mechanisms responsible for the disease. Since it is possible to determine if a woman is a carrier, or if an unborn child has the condition, genetic counseling can provide helpful information and support for the decisions that affected individuals and their families may have to make.