Alport syndrome


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Alport Syndrome

 

Definition

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.

Description

Alport syndrome affects about one in 5,000 Americans, striking men more often and 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. All varieties of the 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 and symptoms

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 [involuntary, rhythmic eye movements (nystagmus), 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. Blood tests can reveal a low platelet level.
In addition, 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 also 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.

Key terms

Albumin — A protein that is important in maintaining blood volume. Low albumin levels is one sign of Alport syndrome.
Dialysis — A technique of removing waste material from the blood. It is used with patients whose kidneys have stopped functioning and can no longer cleanse the blood on their own.
Diuretic — A drug that increases the amount of urine a person produces.
Hematuria — Blood in the urine, Hematuria is a hallmark of Alport syndrome.
Pulmonary edema — Excess fluid in the air spaces of the lungs.
Uremia — The presence of excessive amounts of urea and other waste products in the blood.

Resources

Organizations

American Association of Kidney Patients. 100 S. Ashley Dr., #280, Tampa, FL 33602. (800) 749-2257. http://www.aakp.org.
American Kidney Fund (AKF). Suite 1010, 6110 Executive Boulevard, Rockville, MD 20852. (800) 638-8299. http://216.248.130.102/Default.htm.
National Kidney and Urologic Disease Information Clearinghouse. 3 Information Way, Bethesda, MD 20892. (301) 654-4415. http://www.niddk.nih.gov.
National Kidney Foundation. 30 East 33rd St., New York, NY 10016. (800) 622-9010. http://www.kidney.org.
National Organization for Rare Diseases. P.O. Box 8923, Fairfield, CT 06812. (213) 745-6518. 〈http://www.w2.com〉.

Other

Alport Syndrome Home Page. 〈http://www.cc.utah.edu/∼cla6202/ASHP.htm〉.
"Alport Syndrome." Pediatric Database Home Page. 〈http://www.icondata.com/health/pedbase/files/ALPORTSY.HTM〉.
The Hereditary Nephritis Foundation (HNF) Home Page. 〈http://www.cc.utah.edu/∼cla6202/HNF.htm〉.

Al·port syn·drome

(awl'port),
a genetically heterogeneous disorder characterized by nephritis associated with microscopic hematuria and slow progression of renal failure, sensorineural hearing loss, and ocular abnormalities such as lenticonus and maculopathy; autosomal dominant [MIM*104200, MIM*153640, and MIM*153650], autosomal recessive [MIM*203780], and X-linked recessive [MIM*301050 and MIM*303630] forms exist. The X-linked form is caused by mutation in the collagen type IV α-5 gene (COL4A5) on chromosome Xq; the autosomal recessive form results from mutation in the collagen type IV α-3 gene (COL4A3) or α-4 gene (COL4A4) on 2q.

Alport syndrome

A heterogeneous group of conditions with variable patterns of heredity–most are X-R but also AD and AR frequency 1 in 50,000 Clinical Glomerulonephritis, hematuria, proteinuria, evolving to HTN, nephrotic syndrome, and end-stage renal disease, variably accompanied by sensorineural deafness, colored urine, swelling, cough, poor vision Treatment Kidney transplant may be successful in absence of anti-glomerular basement membrane and anti-tubular antibodies

Al·port syn·drome

(al'pōrt sin'drōm)
A genetically heterogeneous disorder characterized by nephritis associated with microscopic hematuria and slowly progressive renal failure, sensorineural hearing loss, and ocular abnormalities such as lenticonus and maculopathy; autosomal dominant, autosomal recessive, and X-linked recessive forms exist. The X-linked form is caused by mutation in the collagen type IV alpha-5 gene (COL4A5) on chromosome Xq; the autosomal recessive form is due to mutation in the collagen type IV alpha-3 gene (COL4A3) or alpha-4 gene (COL4A4) on 2q.

Alport,

Arthur Cecil, South African physician, 1880-1959.
Alport syndrome - progressive microscopic hematuria.
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