Usher syndrome

What is Usher syndrome?

Usher syndrome is a genetic disorder that can cause vision loss from retinitis pigmentosa, in addition to hearing loss and issues with balance. It is often identified in childhood but can be diagnosed in the teen years or early to mid-adulthood.

There are three types of Usher syndrome, with type 1 being the most severe and type 3 the least severe. Balance, hearing, and vision tests can be used to diagnose this condition, although genetic testing is the only way to identify the disorder subtype.

This condition is rare, affecting approximately four to 17 in 100,000 people. Type 1, which can cause vision and hearing issues early in life, is more common in certain populations, such as eastern and central European Jewish or French Acadian communities.

There is currently no known cure, but early intervention may help slow the progression of vision and hearing loss. A network of healthcare providers can help provide support and treatment for common symptoms and issues.

What are the symptoms of Usher syndrome?

Symptoms of Usher syndrome differ depending on which type you have. Depending on the type of Usher syndrome, vision loss can begin at birth or in early to mid-adulthood.

All individuals with Usher syndrome have a condition called retinitis pigmentosa (RP), a disorder that affects the retina, the light-sensitive tissue at the back of the eye. RP causes the cells of the retina to break down over time.

The degeneration of the retina’s cells leads to a gradual loss of night and peripheral vision. The field of vision continues to narrow until only central vision remains. In some cases, central vision and color vision loss can occur in the later stages.

Retinitis Pigmentosa can cause difficulty:

• Adjusting to changes in brightness.

• Navigating in the dark.

• Identifying small objects in their path.

Individuals with Usher syndrome also usually suffer from hearing loss. Some children are born deaf, while others don’t develop hearing problems until later in life. Children with hearing issues should be identified early so that proper intervention can be provided for speech and communication difficulties.

Usher syndrome may also lead to balance problems due to its impact on the inner ear and visual system. This can result in delays in walking and coordination in children.

READ MORE: Will my sight be affected by my hearing loss?

What are the types of Usher syndrome?

There are three types of Usher syndrome, with symptoms decreasing in severity from type 1 to type 3. The presence and extent of symptoms and age of onset distinguish the three types. In the United States, types 1 and 2 comprise about 95% of all Usher syndrome cases.

Symptoms of type 1 include:

• Vision loss beginning in early childhood, with severe vision loss later in life

• Profound hearing loss at birth

• Balance problems, with children often not walking until at least 18 months

Symptoms of type 2 include:

• Vision loss beginning in teen years or adulthood, with severe vision loss later in life

• Mild to severe hearing loss at birth or in early childhood

• Normal balance

Symptoms of type 3 include:

• Vision loss beginning in early to mid-adulthood

• Normal hearing at birth, with hearing loss beginning in late childhood

• Normal balance, although balance issues may develop later in life

While individuals with types 2 and 3 may benefit from hearing aids, some findings have shown that people with type 1 may benefit more from cochlear implants.

In addition, since many people with type 1 struggle with communication, it can be beneficial for them to learn sign language at an early age.

What are the causes of Usher syndrome?

Usher syndrome is a recessive genetic disorder. This means that a mutated copy of the gene must be inherited from both parents in order to develop the syndrome.

If both parents have the mutated gene but are unaffected (they are “carriers” for the gene), there is a one out of four chance of developing Usher syndrome. If only one parent carries the gene, an individual will not develop the disorder but may be a carrier.

To date, scientists have identified nine different genes that can cause Usher syndrome. Different genes have varying likelihoods of causing types 1, 2 and 3. Genetic testing can be used to identify mutations in the following genes:

• Type 1 – MY07A, USH1C, CDH23, PCH15, USH1G

• Type 2 – USH2A, GPR98, DFNB31

• Type 3 – CLRN1

Even if both parents are carriers for Usher syndrome, they must be carriers for the same mutation on the same gene in order for the disorder to be passed on.

How is Usher syndrome diagnosed?

Usher syndrome is typically diagnosed using a combination of hearing, balance and vision tests as well as laboratory tests.

Some common tests include:

• Comprehensive eye exam – Evaluates the health of the eye and assesses vision, including peripheral vision

• Electroretinography (ERG) – Measures the response of the light-sensitive retina to help diagnose retinitis pigmentosa

• Electronystagmography (ENG) – Analyzes eye movements to detect balance problems

• Videonystagmography (VNG) – Analyzes involuntary eye movements to detect balance problems

• Optical coherence tomographies (OCT) – Provides 3D images of cross-sections of the retina

• Fundus autofluorescence (FAF) testing – Takes pictures of the retina using blue light and fluorescent properties of retinal pigment

• Hearing evaluations – Measure hearing by testing a variety of sounds and frequencies

Genetic testing is the most accurate way to diagnose Usher syndrome, allowing doctors to identify the particular subtype of Usher syndrome.

What are the treatment options?

There is currently no cure for Usher syndrome. Early intervention and treatment can help slow the progression of the condition and help individuals retain more of their hearing and eyesight. If you notice symptoms of decreased hearing, vision or balance in your child, it is important to notify your child’s doctor as soon as possible.

Common treatments and adaptive strategies include:

• Hearing aids

• Cochlear implants

• Assistive listening devices

• Vision aids, including prescription glasses

• Vision rehabilitation services

• Learning American Sign Language or another sign language

• Learning braille

• Speech therapy services

• Mobility and orientation training for balance

• Auditory training

Research by the National Eye Institute and the Foundation Fighting Blindness suggests that taking vitamin A could help slow the progression of RP, potentially helping individuals with Usher syndrome maintain their peripheral and night vision longer.

Taking too much vitamin A can be dangerous, however. So, it is important to discuss any treatments with your doctor prior to beginning supplements. The study also did not include people with type 1 Usher syndrome, so it is unknown whether increased vitamin A would help individuals with type 1.

As gene therapy continues to evolve, new treatments may develop that target the mutations responsible for Usher syndrome.

When should you see a doctor?

If your child has symptoms of vision or hearing loss or balance issues, speak to your child’s physician as soon as possible. You should schedule an appointment if your child is exhibiting symptoms of Usher syndrome, including:

• Hearing loss

• Vision loss

• Difficulty navigating in the dark

• Balance or coordination problems

At the appointment, it can be helpful to ask questions such as:

• Would my child benefit from hearing aids or a cochlear implant?

• What are the best options for vision aids for my child?

• How can I help my child’s balance and/or coordination problems?

• Should I look into ASL or Braille lessons for my child?

• How can I help my child deal with vision and hearing loss?

• Should I or my family undergo genetic testing?

Early intervention is critical for children with Usher syndrome. In addition, routine, comprehensive eye exams and physical exams are the first step in evaluating your child’s health and vision needs.

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Page published on Tuesday, June 27, 2023

Page updated on Wednesday, July 5, 2023