Merck Manual

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Alport Syndrome

(Hereditary Nephritis)

By

Frank O'Brien

, MD, Washington University in St. Louis

Full review/revision Jul 2021 | Modified Sep 2022
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Topic Resources

Alport syndrome is a hereditary (genetic) disorder that results in glomerulonephritis in which kidney function is poor, blood is present in the urine, and deafness and eye abnormalities sometimes occur.

Alport syndrome is usually caused by a defective gene on the X chromosome (female sex chromosome), but it sometimes results from an abnormal gene on a nonsex (autosomal) chromosome. Other factors influence how severe the disorder is in a person who has the defective gene. Alport syndrome can cause chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more , sometimes with loss of most kidney function (kidney failure).

Symptoms

Females with the defective gene on one of their two X chromosomes usually do not have symptoms, although their kidneys may function somewhat less efficiently than normal. Most of these females have some blood in the urine. Occasionally, a female loses most kidney function (kidney failure Overview of Kidney Failure Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney failure has many possible causes. Some lead to a rapid decline in kidney function... read more ).

Males with the defective gene on their one X chromosome develop more severe problems because males do not have a second X chromosome to compensate for the defect. Males usually develop kidney failure between the ages of 20 and 30, but in some males, the defective gene does not cause kidney failure until after age 30.

Alport syndrome can affect other organs. Hearing problems, usually an inability to hear sounds in the higher frequencies, are common. Cataracts Cataract A cataract is a clouding (opacity) of the lens of the eye that causes a progressive, painless loss of vision. Vision may be blurred, contrast may be lost, and halos may be visible around lights... read more Cataract can also occur, although less often than hearing loss. Abnormalities of the corneas, lenses, or retina sometimes cause blindness.

Diagnosis

  • Urinalysis

  • Kidney biopsy

  • Molecular genetic analysis

Genetic testing is usually offered to people with a family history of kidney disease.

Treatment

NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
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