Alport Syndrome - Facts and Information
- Publish Date: 2009/11/21 - (Rev. 2009/11/23)
- Author: Thomas C. Weiss
Outline: Alport syndrome is a form of genetic disease involving a mutation that affects a persons ears eyes and kidneys.
Main DigestAlport syndrome is a form of genetic disease involving a mutation that affects a person's ears, eyes and kidneys. The syndrome is named for Doctor Alport, who described a British family whose members developed both deafness and renal disease in the year 1927.
Dr. Alport made note of the fact that the male members of the family died because of the kidney issues they were presented with, while the women in the family were not as greatly affected and lived until an old age. Alport syndrome is also known by the names Hereditary nephritis, Hemorrhagic Familial Nephritis, Hematuria Nephropathy Deafness, and Hereditary Deafness Nephropathy.
Since then, medical science has discovered that the majority of people with Alport syndrome have it because of a mutation in the collagen gene COL4A5, which encodes for the alpha-5 chain of collagen type IV; it is located on the X chromosome. The fact that women have two X chromosomes finds women affected by Alport Syndrome with one regular copy of the gene and one that is not. Men have one copy of the X chromosome; should they inherit the COL4A5 mutation, the gene that is not regular is the one copy of the gene they have, and the effects are more severe.
Type IV collagen is present in, 'basement membranes,' (BM) which are selective barriers between a person's cells. In a person's kidneys the glomerular BM filters out waste products in the person's urine, while keeping molecules that are useful within their bloodstream. In Alport syndrome, the abnormal collagen disrupts this BM filter; what this can lead to is a loss of red blood cells and proteins into the person's urine. The presence of blood in a person's urine is a common sign to all forms of Alport syndrome. In a person's ear, the presence of abnormal collagen in their cochlea has the result of progressive deafness, resulting in an inability to hear high tones which is lost first. The presence of abnormal collagen can also affect the lens of the person's eye.
Causes and Risk Factors of Alport Syndrome
Alport syndrome is caused by a mutation in a gene for a protein in connective tissue referred to as collagen. While the disorder is uncommon, it largely affects men. Women can transmit the gene for Alport syndrome to children, despite a lack of presentable symptoms. The risk factors for Alport syndrome include:
Hearing loss prior to age 30
Family history of Alport syndrome
End-stage kidney disease in male relatives
Symptoms of Alport Syndrome
The person with Alport syndrome will commonly not experience any symptoms at first. What follows is the progressive destruction of the persons glomeruli, which leads to blood in their urine and decreasing effectiveness of their kidney's ability to filter appropriately. The person experiences a progressive loss of kidney function in general, as well as a buildup of wastes and fluids in their body. Women with Alport syndrome experience symptoms that are commonly milder or no symptoms at all. For men, the symptoms are generally more severe and worsen at a quicker rate. The symptoms of Alport syndrome include:
Blood in the urine
Abnormal urine color
Swelling around the eyes
Ankle, feet, and leg swelling
Loss of hearing, more common in males
Decrease or loss of vision, more common in males
People with Alport syndrome can progress to end-stage renal disease at an early age, between adolescence and the age of forty. People with the syndrome, oftentimes women, might not experience any symptoms at all. Symptoms of either heart failure or kidney failure can be present or develop in people with Alport syndrome.
Signs and Tests for Alport Syndrome
Signs of Alport syndrome can include changes to the person's eye, to include the posterior inner part of their eye, the cataracts, lens, or lens protrusion. The person may have blood in their urine, or experience an elevation in their blood pressure. There are some different tests that can be performed in relation to Alport syndrome; these include:
Red blood cell count
A doctor tests to find out if the person's urinalysis shows blood, protein or other abnormalities, while they test BUN and creatine for elevated levels. The doctor checks for a decrease in the person's red blood cell count or hematocrit. The person may present with a positive Hematuria test, or have an Audiometry that shows nerve deafness. A Renal biopsy may show chronic glomerulonephritis that has changes which are typical of Alport syndrome.
Treatment of Alport Syndrome
Treatment goals related to Alport syndrome include both monitoring and control of the progression of the disease, as well as treatment of the person's symptoms. One of the most important things to do is control any symptoms related to high blood pressure. Treatment of chronic renal failure becomes a necessity. Dietary modifications, fluid restrictions, as well as other forms of treatments are involved. As chronic renal failure progresses towards end-stage renal failure in the person with Alport syndrome, dialysis or a kidney transplant are required. Gene therapy might one day be able to give people with Alport syndrome a cure through replacement of the COL4A5 gene.
The potential for repair of either the person's anterior lenticonus or cataracts in their eyes is possible. The loss of hearing the person with Alport syndrome may experience is likely to be permanent. Education regarding the disease, as well as counseling, can both be helpful. People with Alport syndrome can benefit from learning sign language or how to lip read. Hearing aids also provide assistance. Young men who experience this syndrome need to use protective devices for their hearing in loud environments. Families with Alport syndrome may also benefit from genetic counseling.
Women with Alport syndrome commonly have a regular life span and do not experience signs of the disease, with the exception of blood in their urine. On rare occasion, women will experience swelling, pressure, as well as nerve deafness as complications of pregnancy. Men with Alport syndrome experience visual difficulties, deafness, and kidney failure, commonly by the age of fifty. The complications of Alport syndrome include a decrease or loss of vision, end-stage renal disease, permanent deafness, and chronic renal failure. Awareness of the risk factors for Alport syndrome, to include the presence of a family history of the disease, can permit the condition to be detected at an early stage.
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