Definition & Facts
Alport syndrome is an inherited disorder. It is the result of genetic mutations that occur and are passed on to offspring. This syndrome is most often an X-linked disorder that affects males more often and more severely than females. It is characterized by both kidney disease and deafness. Some cases also have been shown to involve eye problems.
The disease was named for A. Cecil Alport, a British doctor. In 1927, he described the hereditary combinations of nephritis and deafness in three generations of a family. Similar families were discovered soon after. Alport syndrome is a rare disease that affects less than 200,000 people in the United States. It accounts for only about two percent of adults experiencing kidney failure.
Symptoms & Complaints
One sign seen in the early stage of the disease is blood in the urine (hematuria). Still, this usually is only seen microscopically, so many people might not notice it unless it is picked up on a routine urinalysis.
Symptoms in later stages may include swelling in the body as the kidneys cannot get rid of wastes, increased blood pressure (hypertension), and pain in the lower abdominal area where the kidneys are located.
Another symptom of Alport syndrome is hearing loss. In the most common form of the syndrome, males can have hearing loss in their teens while females may not experience it until later in life. In less common forms, both males and females experience hearing loss either during childhood or later in life. Hearing loss usually occurs before kidney failure.
Additionally, the syndrome can affect the eyes. Eye symptoms may include abnormal shape of the lens that can lead to a slow decline in vision, corneal erosion, unusual coloring of the retina, and macular holes.
Alport syndrome is caused by a genetic mutation that affects the type IV collagen family of proteins. These collagen proteins are found in many body tissues, but particularly in those called basement membranes. They help the structures of the tissues and are found specifically in the kidney, the inner ear, and the eye. There are three types of this syndrome, and each involves a different inheritance pattern. The types include:
- X-linked-This is the most common, and it affects males more severely than females.
- Autosomal recessive-Both parents have the genetic mutation and pass it onto their child.
- Autosomal dominant-This is the rarest type in which only one parent must have the genetic mutation in order to pass it onto the child.
Patients with Alport syndrome will experience damage to the collagen structures during the normal filtering process that the kidneys undergo. Scar tissue will form and cause a decrease in the function of the kidneys and eventually, kidney failure. Similar events happen in the ear and in the eye, and they can cause deafness and serious eye problems as well.
Diagnosis & Tests
Since Alport syndrome is so rare, it is often overlooked when a doctor is looking for a diagnosis. When a patient visits the doctor, the doctor is likely to first complete a medical history and physical examination.
It is important for patients to relay all family history since this disease is hereditary and conveying the existence of family members with similar symptoms can help lead to a quicker diagnosis. The physical exam may reveal a tenderness in the abdomen where the kidneys are located as well as high blood pressure and swelling, especially in the extremities.
The doctor is likely to order a urinalysis to check for blood in the urine and protein in the urine sample. Additionally, blood work should be completed. The doctor should order the blood urea nitrogen test (BUN test) which helps test kidney function. A serum creatine test and a complete blood count may also prove useful.
In addition, hearing should be tested and the ear examined. This may involve a computed tomography (CT) scan of the head to enable to physician to see the structures of the inner ear. A visit to the eye doctor may be revealing as well. One telltale sign of Alport syndrome is a dot-and-fleck retinopathy, an unusual coloring of the retina that can help in the diagnosis of the disease.
Treatment & Therapy
There is no cure to Alport syndrome, so treatment revolves around monitoring and controlling the disease while reducing symptoms. The doctor is likely to recommend a diet that does not stress the kidneys more than necessary. This type of diet generally limits the amounts of salt, potassium, fluids, and proteins ingested. The doctor will likely have specific guidelines to follow.
In addition, it may be important to take medications to control high blood pressure in order to slow the progress of the kidney disease. When a patient reaches end-stage renal disease and the kidneys fail, they will need to undergo dialysis several times per week and/or have a kidney transplant.
Hearing loss can sometimes be treated with hearing aids. The eyes are treated as needed as well. For example, a badly shaped lens may be replaced by a synthetic version.
Prevention & Prophylaxis
In addition, when the genetic link is known, this may lead to early detection of Alport syndrome. Early detection leads to the best prognosis because medications can be given to help slow the progress before any damage is actually done.