What is Alport Sydrome?
Alport Syndrome is a genetically inherited disease of the kidneys. It may also affect the inner ears and eyes. It is caused by genetic mutations of the collagen IV family of proteins. These proteins are a major part of tissue structures called basement membranes that are present in all tissues including the kidney, inner ear, and eye. Genetic mutations of collagen IV cause thinning and splitting of the glomerular basement membrane. Ultimately, this process causes scarring throughout the kidney and may lead to kidney failure.
How is Alport Syndrome Diagnosed?
A diagnosis of Alport syndrome is considered in a person with kidney issues (blood and/or protein in urinalysis) and hearing loss. Sometimes vision screening is also helpful.
Kidney biopsies can also show an absence of collgen tissue and can be tested for the precence of specific genes (COL4A3, COL4A4, and COL4A5). This information can even sometimes determine the specific genetic form of the disease.
Because Alport Syndrome is a hereditary disease, genetic testing will confirm the diagnosis.
What are the Symptoms of Alport Syndrome?
Symptoms of Alport Syndrome may include:
- Hematuria – Blood in urine
- Abnormal urine color
- Proteinuria – Large amounts of protein “spilling” into the urine
- Edema – Swelling in parts of the body, most noticeable around the eyes, hands and feet, and abdomen.
- Foamy urine
- Low Blood Albumin Levels
- Decreased or loss of vision (more common in males)
- Flank pain.
- Loss of hearing (more common in males)
- High Cholesterol in some cases
- High Blood Pressure in some cases
- Tendancy to form Blood Clots if spilling large amounts of protein
- Kidney Failure in only some cases
Who gets Alport Syndrome?
Alport Syndrome is estimated to affect approximately 1 in 5,000-10,000 people in the the United States, and is considered a rare disease. It most often affects males. Women can pass the gene for the disorder onto their children, even if they have no symptoms.
Most cases of AS are caused by a mutation in the collagen gene COL4A5. This gene is located on the X chromosome. Women have two X chromosomes (XX) and they usually have one normal and one abnormal copy of the gene. Women generally have a less severe form of the disease. Because Men only have one copy of the X chromosome (XY) and it is abnormal, they generally have a more severe form of AS. About 50% of males with X-linked disease require dialysis or kidney transplantation by age 25 years, and about 90% develop end-stage renal disease (ESRD) before 40 years of age. In female patients with X-linked Alport Syndrome, progression to ESRD was previously thought to be rare. However, recent observations have shown that as many as 12% of female patients also develop ESRD by the age of 40 years; this rate increases to 30% by the age of 60 years and 40% by age 80 years (1).
In autosomal recessive and autosomal dominant Alport Syndrome the severity of disease affects male and females the same. Patients with the autosomal recessive form of Alport Syndrome are likely to develop kidney failure by youn adulthood. Patients with autosomal dominant Alport Syndrome tend to not experience kidney failure until later into middle age.
How is Alport Syndrome Treated?
It is very important for people with Alport Syndrome to be seen regularly by a nephrologist to monitor the effects of the disease. Patients should be on a medication that slows the progression of kidney damage. These medications are called ACE-inhibitors (angiotensin converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers).
The Alport Syndrome Research Collaborative developed Clinical Practice Recommendations aimed at standardizing therapy for children with Alport Syndrome. Guidelines for treatment of adult Alport Syndrome patients are also available (1).
Regular hearing and vision evaluation is also important.
Your nephrologist may also recommend:
- Diuretics to help eliminate excess fluids in the body
- Low Sodium diet help to control edema
- Anticoagulants to prevent blood clots
- Blood Pressure medications to lower high blood pressure
- Statins to lower the cholesterol level
- Maintaining a healthy diet: Correct amounts of protein and fluid intake according to your nephrologist’s recommendations. A healthy diet consists of low salt with emphasis on fruits and vegetables, low in saturated fat and cholesterol.
- Not smoking
- Genetic Counseling
For more detailed information regarding Alport Syndrome visit www.alportsyndrome.org