Usher’s syndrome – Diagnostics – Overview of Information and Clinical Research

Usher syndrome is a rare genetic disease that affects both hearing and vision, and sometimes balance. Because the symptoms appear at different stages of life and vary in severity, proper diagnosis requires a careful combination of hearing tests, vision exams, balance assessments, and genetic testing to distinguish it from other conditions.

Introduction: Who Should Get Tested for Usher Syndrome

If you notice that your child has hearing loss or deafness from birth, it is important to consider the possibility of Usher syndrome. Many children with this condition are born deaf or with significant hearing problems, but the vision issues may not become apparent until later in childhood or adolescence. This delay between the identification of hearing loss and the diagnosis of vision problems can sometimes stretch to 5 to 10 years, which is why early and comprehensive diagnostic testing is so important.^[5]

Parents should seek diagnostic evaluation if their child shows signs of hearing loss combined with difficulty seeing in the dark, trouble moving around in dimly lit spaces, or taking longer to adjust to changes in lighting. These are often the first signs of retinitis pigmentosa, the eye disease that causes progressive vision loss in people with Usher syndrome. Children may also trip over objects they don’t see in their path or struggle with tasks that require side vision.^[1]

In some cases, children with Usher syndrome type 1 may also have difficulty keeping their balance, which can delay milestones like sitting up independently or learning to walk. If a baby or young child is born deaf or with severe hearing loss and also struggles with balance, this combination of symptoms should prompt immediate medical attention.^[2]

Because Usher syndrome is inherited from both parents, genetic testing and early screening have become more common. Even if there is no known family history of the condition, both parents may be carriers of the gene mutation without showing any symptoms themselves. If you have a family member with combined hearing and vision loss, or if your child has unexplained sensory issues, it is advisable to consult with a doctor who can arrange for comprehensive diagnostic testing.^[8]

⚠️ Important

Because newborn hearing screening is now widely available, hearing loss is often identified very early, sometimes as young as 6 months old. However, the diagnosis of Usher syndrome itself may not happen until much later, when vision problems start to appear. This is why it is crucial to ask your child’s doctor about Usher syndrome if hearing loss is detected, so that vision monitoring can begin early.

Diagnostic Methods: How Doctors Identify Usher Syndrome

Diagnosing Usher syndrome involves a combination of tests that assess hearing, vision, balance, and genetics. Because the condition affects multiple sensory systems, doctors need to look at the complete picture to distinguish Usher syndrome from other conditions that may cause hearing or vision problems on their own.

Hearing Tests

The first step in diagnosing Usher syndrome is usually a hearing test. Many children with this condition are born with moderate to profound hearing loss, depending on the type of Usher syndrome they have. Audiologists, who are specialists in hearing, use a variety of tests to measure how well a child can hear different sounds and frequencies.^[5]

Hearing tests for Usher syndrome typically assess the severity and type of hearing loss. The hearing loss in Usher syndrome is called sensorineural hearing loss, which means it is caused by problems in the inner ear or the nerve pathways that carry sound signals to the brain. This type of hearing loss is different from hearing problems caused by ear infections or blockages, which affect the outer or middle ear.^[3]

Because hearing loss can be a symptom of many different conditions, audiologists also look for patterns that might suggest Usher syndrome. For example, children with type 1 Usher syndrome are often born profoundly deaf, while those with type 2 have moderate to severe hearing loss that primarily affects high-frequency sounds, making it hard to hear soft speech sounds like “d” and “t.” Type 3 is rare and involves hearing that is normal at birth but gradually worsens over time.^[3]

Vision Tests

Vision testing is critical for diagnosing Usher syndrome because the condition always involves retinitis pigmentosa, a progressive eye disease. An eye doctor, also called an ophthalmologist, will perform a comprehensive dilated eye exam, which is a simple and painless procedure. During this exam, the doctor puts special eye drops into your child’s eyes to widen the pupils, allowing them to see the back of the eye more clearly.^[1]

The exam includes checking the retina, which is the light-sensitive tissue at the back of the eye. In people with Usher syndrome, the cells in the retina gradually break down over time. The doctor will look for signs of this breakdown, such as changes in the appearance of the retina or the presence of dark spots. These changes indicate that retinitis pigmentosa is present.^[2]

One important part of the vision exam is a visual field test, which checks your child’s side (peripheral) vision. In Usher syndrome, peripheral vision is often the first to be affected, leading to a condition called tunnel vision, where the person can only see what is directly in front of them. This test helps doctors understand how much vision has already been lost and how the condition is progressing.^[1]

Doctors may also use additional tests to get more detailed information about the retina. One such test is electroretinography (ERG), which measures how well the retina responds to light. This test involves placing a sensor near the eye to detect electrical signals produced by the retina when exposed to light. A weaker response can indicate that the retina is damaged.^[1]

Another test called optical coherence tomography (OCT) uses light waves to take detailed pictures of the retina. These images allow the doctor to see the different layers of the retina and identify any areas of thinning or damage. This test is especially useful for monitoring how the disease is progressing over time.^[1]

Balance Tests

For children with Usher syndrome type 1, balance problems are a key feature that helps distinguish this type from others. The balance system is located in the inner ear, in a part called the vestibular system. When this system is not working properly, children may have trouble sitting up, standing, or walking at the expected ages.^[8]

Doctors can test balance using a procedure called videonystagmography. This test checks for abnormal eye movements that occur when the balance system is not functioning correctly. It helps doctors determine whether the vestibular system is affected, which is a strong indicator of Usher syndrome type 1.^[1]

Balance testing is particularly important because not all children with hearing and vision loss have balance problems. Children with Usher syndrome type 2 and most with type 3 have normal balance, so the presence or absence of balance issues helps doctors narrow down which type of Usher syndrome a child has.^[3]

Genetic Testing

Genetic testing is the most definitive way to diagnose Usher syndrome and determine which specific type a person has. Because Usher syndrome is caused by changes (mutations) in specific genes, a genetic test can identify which gene is affected. Scientists have identified at least 9 to 11 different genes that can cause Usher syndrome, depending on the source.^[1]^[2]

Genetic testing involves taking a small sample of blood or saliva and analyzing it in a laboratory to look for mutations in the genes known to cause Usher syndrome. The test can confirm the diagnosis even before vision problems become obvious, which is especially helpful for families who want to start planning for the future as early as possible.^[3]

Knowing the specific genetic mutation can also provide information about how the disease is likely to progress and whether a child might be eligible for certain research studies or clinical trials. Different types of Usher syndrome progress at different rates, so genetic testing helps doctors and families understand what to expect.^[7]

Because Usher syndrome is inherited in an autosomal recessive pattern, both parents must carry a copy of the mutated gene for their child to develop the condition. This means that parents who are carriers do not have symptoms themselves, and they may not even know they carry the gene. Genetic testing can also help other family members understand their risk of being carriers, which can be useful for family planning decisions.^[8]

Diagnostics for Clinical Trial Qualification

Clinical trials are research studies that test new treatments or therapies for diseases like Usher syndrome. To participate in a clinical trial, patients usually need to meet certain criteria, which often include specific diagnostic tests to confirm the diagnosis and measure the severity of their condition.

For Usher syndrome clinical trials, genetic testing is almost always required. Researchers need to know which specific gene mutation is causing the condition because many experimental treatments are designed to target specific genetic subtypes. For example, a gene therapy trial for type 1B Usher syndrome, caused by mutations in the MYO7A gene, would only be open to patients with that exact mutation.^[13]

Vision testing is also a standard part of clinical trial qualification. Researchers typically use tests like ERG and OCT to measure how much retinal damage has occurred and how much vision the patient still has. Some trials may only accept patients at certain stages of vision loss—for example, those who still have some central vision but have lost most of their peripheral vision. These measurements help researchers determine if a treatment is working by comparing vision before and after the intervention.^[1]

Hearing tests are used to assess the degree of hearing loss and determine whether a patient’s hearing is stable or worsening. Some clinical trials may focus specifically on vision treatments, while others may aim to preserve both hearing and vision. Understanding the baseline hearing level is important for tracking any changes during the trial.^[5]

In addition to these sensory tests, clinical trials may also require general health assessments, such as blood tests, to ensure that participants are healthy enough to receive the experimental treatment. Some trials also collect detailed medical histories and ask about the age when symptoms first appeared, as this information helps researchers understand how the disease progresses and which patients are most likely to benefit from a particular therapy.^[13]

⚠️ Important

If you or your child is interested in participating in a clinical trial, it is important to work closely with your healthcare team to gather all the necessary diagnostic information. Many trials have very specific requirements, and having recent test results can speed up the enrollment process. Ask your doctor about keeping copies of your test results and genetic testing reports so they are ready when needed.

Prognosis and Survival Rate

Prognosis

The prognosis for people with Usher syndrome varies depending on the type and the severity of symptoms. While there is currently no cure, the condition does not affect life expectancy. People with Usher syndrome can live full lives with the help of supportive treatments and assistive technologies.^[2]^[9]

The progression of vision and hearing loss depends on which type of Usher syndrome a person has. In type 1, vision loss typically begins in the first decade of life and progresses to severe vision loss by midlife. Hearing loss is profound from birth. Children with type 1 also experience balance problems that can affect motor development.^[1]

People with type 2 Usher syndrome generally have a slower progression of vision loss, which usually begins in the teenage years. Hearing loss is moderate to severe from early childhood but does not typically worsen over time. Because balance is not affected in type 2, individuals can develop motor skills normally.^[3]

Type 3 is the rarest form and has the most variable progression. Hearing and vision are typically normal at birth, with hearing loss beginning in late childhood and vision loss starting in adolescence or early adulthood. Some people with type 3 also develop balance problems, but not all do.^[3]

The psychological impact of Usher syndrome can be significant, as individuals must continuously adapt to progressive sensory loss. Many people experience grief and emotional challenges as their vision narrows and communication becomes more difficult. However, with proper support, counseling, and adaptive strategies, many individuals with Usher syndrome lead independent and fulfilling lives.^[18]^[19]

Survival rate

Usher syndrome does not reduce life expectancy. The condition affects the senses of hearing, vision, and sometimes balance, but it does not impact other vital organs or systems in the body. People with Usher syndrome have a normal lifespan and can live as long as anyone else.^[2]^[9]

While the sensory losses associated with Usher syndrome can create challenges in daily living and may require significant adaptations over time, the condition itself is not life-threatening. With appropriate support, including vision and hearing aids, orientation and mobility training, and access to assistive technologies, individuals with Usher syndrome can maintain a good quality of life throughout their normal lifespan.^[11]

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