How Alport syndrome affects the eyes

Understanding Alport syndrome

Alport syndrome is a progressive kidney disease. It can also affect hearing and cause eye abnormalities. Some individuals can develop progressive hearing loss. But vision is not usually impaired due to eye abnormalities. Gene mutations in collagen cause Alport syndrome.

Collagen is a protein present throughout the body. This includes in the three associated organs — kidneys, ears and eyes. Collagen is necessary for maintaining healthy tissue.

The gene mutations that cause Alport syndrome can lead to kidney failure, hearing loss and vision problems.

The earliest signs of Alport syndrome are kidney related. Signs include blood or protein in the urine, high blood pressure, and swelling in the legs, ankles, feet and around the eyes. The first sign, blood in the urine, develops early in life. This disease attacks the glomeruli — the tiny filters inside your kidneys.

Damage to the glomeruli means the kidneys cannot properly filter waste and fluid in the body. This can ultimately lead to kidney failure.

Problems relating to ears and eyes include progressive hearing loss and eye abnormalities. Eye issues are not common during the childhood years. They typically appear later in the teenage years as the glomeruli become more damaged.  Depending on the type of Alport syndrome, eye changes may be more common in males than in females diagnosed with the disease.

Types of Alport syndrome

There are three different genetic types of this condition.

The most common form is X-linked Alport syndrome (XLAS). This type results from a mutation on the X chromosome and occurs in about 80% of the people diagnosed with Alport syndrome.

XLAS is more severe in male patients than in females. Approximately 90% of males develop kidney failure by age 40 if they don’t receive treatment. Kidney failure is less common and occurs more slowly in female patients.

The second most commonly diagnosed form is autosomal recessive Alport syndrome (ARAS). This version affects males and females equally. ARAS occurs when both parents carry the abnormal gene and pass it on to their child.

The rarest form is autosomal dominant Alport syndrome (ADAS). This form happens when one parent has the condition and passes on the abnormal gene. Thus, Alport syndrome requires only one copy of the abnormal gene.

Alport syndrome is hereditary and is estimated to affect one in every 5,000 to 10,000 individuals. Signs and symptoms may differ due to age, gender and inherited type of Alport syndrome. But with every type of Alport syndrome, the kidneys are primarily affected.

Hearing problems often appear in late childhood or early adolescence. Eye abnormalities can become clear in teen years but may not be detected until adulthood.

Ocular manifestations

Alport syndrome can lead to kidney failure and hearing loss. But the eye abnormalities caused by the disease rarely result in vision loss. Ocular abnormalities caused by Alport syndrome affect the cornea, the lens and the retina. These generally present after kidney issues have developed.

Eye abnormalities are not common in ADAS. In individuals with XLAS and ARAS, the abnormalities have similar characteristics.

Anterior lenticonus

Though considered a rare condition, one ocular manifestation of Alport syndrome is anterior lenticonus. Anterior lenticonus is an abnormal shape of the eye’s lens. It occurs when the lens protrudes into the anterior chamber. The anterior chamber is the part of the eye between the cornea and the iris.

Anterior lenticonus is not present at birth but develops over time. One indication of anterior lenticonus is the need for frequent changes in eyewear prescriptions. This symptom is a convenient diagnostic indicator for Alport syndrome. Almost everyone with anterior lenticonus has Alport syndrome.

Anterior lenticonus is present in approximately 15% to 20% of patients with X-linked and autosomal recessive Alport syndrome.

Lens replacement surgery is the recommended treatment for anterior lenticonus. This surgery is essentially the same procedure that is performed for cataracts. A new lens permanently replaces the abnormal one.

Dot-and-fleck retinopathy

This condition causes pigment (color) changes in the retina. It becomes more apparent as kidney functions decline due to Alport syndrome. The abnormal coloring is seen as yellow and/or white dots or flecks on the retina and is sometimes called “fleck retina.”

This condition does not generally result in any vision abnormalities. Dot-and-fleck retinopathy is rarely detected in childhood. Instead, it only becomes clear when kidney failure begins, progressing alongside the deterioration of the kidneys.

Every male exhibiting dot-and-fleck retinopathy should be tested for Alport syndrome. This condition is present in 85% of adult males affected by the disease.

No treatment is necessary for dot-and-fleck retinopathy as it does not affect vision.

Recurrent corneal erosion

This condition occurs when the cornea’s outer layer — the epithelium — does not attach properly to the underlying layers.

These corneal erosions can cause irritation and discomfort. This includes recurring eye pain, itchiness, redness, light sensitivity and eye watering. These symptoms can lead to blurry vision at times.

Some steps you can take to protect your cornea and eyes include:

• Wearing protective lenses

• Abstaining from rubbing your eyes

• Lubricating your eyes

• Informing your eye doctor that you have Alport syndrome

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Macular hole

This is a rare complication among patients with Alport syndrome. In fact, fewer than 5% develop a macular hole.

A macular hole can result due to progressive thinning of the retina. The macula is located at the center of the retina and provides detailed vision of what is directly ahead of you. A macular hole can impair vision.

The occurrence of a macular hole in younger patients is directly related to Alport syndrome.

Optical coherence tomography (OCT) can detect a macular hole by providing cross sectional images of the retina. A macular hole can affect central vision. Treatment may be necessary to prevent more serious complications from occurring. 

Other eye symptoms

There are a few additional or secondary symptoms related to Alport syndrome.

• Nearsightedness or myopia – This symptom is sometimes associated with Alport syndrome. But, myopia is a common condition affecting one-in-four people in the world. Alport syndrome is not usually the cause.

• Astigmatism – Astigmatism may occur due to anterior lenticonus. Astigmatism results in blurred vision and occurs when the curve of the cornea or the lens inside the eye is egg-shaped instead of ball-shaped.

• Corneal posterior polymorphous dystrophy – This is an uncommon condition that causes changes to the cornea. It is often bilateral and can affect vision.

• Cataracts – Anterior lenticonus can lead to cataracts, cloudy areas in the lens that can cause decreased visual acuity.

Diagnosis and treatment

It is very important for people with Alport syndrome to have regular, comprehensive eye exams. Eye doctors can monitor and help patients maintain the health of their eyes.

Diagnostic procedures

A urinalysis is the most effective means of testing for Alport syndrome. A blood test or kidney biopsy may also be necessary to determine if you have Alport syndrome.

In addition to a comprehensive eye exam, the following tests may be ordered by your eye doctor:

• Retinal photographs

• OCT

• Wide field color imaging

• Common eye tests such as slit lamp exam, dilated eye exam and ophthalmoscopy

Genetic testing can also confirm the diagnosis since Alport syndrome is an inherited condition. It can also pinpoint the specific type of Alport syndrome you have.

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Treatment

Alport syndrome affects multiple areas of the body. So, several medical specialties work together to treat the symptoms.

Options for treating or slowing the effects of kidney disease include taking high blood pressure medication. Water pills and limiting salt intake may also be recommended. In the event of kidney failure, a kidney transplant is the most successful treatment.

As hearing loss progresses in Alport syndrome patients, hearing aids are often required.

Your eye doctor can prescribe protective or corrective lenses. They can also address any discomfort due to recurrent corneal erosions. Rarer, more serious cases may require additional procedures or eye surgery.

Managing vision care

Some Alport syndrome patients never develop any eye issues. If you have Alport syndrome, inform your eye doctor of your diagnosis. This is important even if you are not experiencing any eye problems. Your doctor should always be aware of your condition and monitor you for any eye-related signs and symptoms.

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Page published on Tuesday, July 4, 2023

Page updated on Tuesday, July 11, 2023

Medically reviewed on Monday, June 26, 2023