Usher syndrome is a condition that causes problems with hearing and vision. People with Usher syndrome are either born deaf or lose hearing throughout their childhood, teenage years, and early adult life. They also lose their sight and can have balance problems.
Usher syndrome is a genetic disorder, which means that parents can pass it on to their children, even if neither parent has symptoms of the disease.
Types of Usher Syndrome
There are three types of Usher syndrome based on the degree of hearing and balance problems at birth. Children with type 1 are born completely deaf and have severe balance problems, while children with type 2 or 3 are born with moderate hearing loss or normal hearing that becomes worse over time. Type 2 usually does not cause balance problems. Types 1 and 2 are the most common, and make up 90%-95% of all cases in the United States.
In addition to hearing loss and balance problems, all types of Usher syndrome cause retinitis pigmentosa, a condition that causes reduced eyesight, night blindness, and eventually total blindness.
All three types of Usher syndrome cause problems with hearing and vision, while type 1 and type 3 also cause balance problems. These symptoms can be different for each person, and can get worse slowly or more quickly depending on the type of the disease.
- Deafness. Children with type 1 Usher syndrome are completely unable to hear in either ear from the time they are born.
- Vision. Children with type 1 Usher syndrome start to have problems with their vision while they are young, usually before they are 10 years old. At first, they can’t see at night, but this gets worse until they are completely blind.
- Balance. This type of Usher syndrome causes balance problems, and your child might not be able to sit without being held. They might start walking later than usual, at around 18 months old.
- Hearing. Children born with type 2 Usher syndrome have some hearing loss, but may be able to hear with hearing aids, and many of them can talk.
- Vision. People with type 2 Usher syndrome also have vision problems, but these don’t show up as fast as they do for people with type 1, and usually start in the teenage years.
- Balance. Type 2 Usher syndrome doesn’t cause balance problems like type 1 and type 3.
- Hearing. Children with type 3 Usher syndrome causes are born with normal hearing that gets worse as they grow into teenagers and adults.
- Vision. People with type 3 Usher syndrome start to have night blindness in their teens, and are usually legally blind by mid-adulthood.
- Balance. Type 3 Usher syndrome can affect balance, but this is usually not as serious as it is with type 1.
Usher syndrome is caused by genes in your child’s DNA, the code that has all of the information about their body. It is inherited, which means that parents can pass these genes on to their children. Even parents who don’t have symptoms of Usher syndrome can be carriers for the disease, meaning they have the genes that cause the disease and can pass them on to their children.
Usher syndrome is a recessive disorder. This means that both parents need to be carriers for the gene that causes Usher syndrome for their child to be at risk. If both parents are carriers, then they have:
- A 1 in 4 (25%) chance of having a child with the symptoms of Usher syndrome
- A 2 in 4 (50%) chance of having a child who is a carrier of the gene that causes Usher syndrome (but no actual symptoms)
- A 1 in 4 (25%) chance of having a child who doesn’t have Usher syndrome and isn’t a carrier
If your doctor thinks that your child might have Usher syndrome, they will do a physical exam of your child and may also do some tests that will measure your child’s hearing, vision, and balance. These tests can include:
- Visual field test. This test measures the peripheral vision, the part of your vision that is to the outside instead of right in front of you.
- Electroretniogram [ee-LEK-troh-RET-in-oh-GRAM]. This test measures how much your eyes respond to light, which can show how much vision remains.
- Retinal examination. Your doctor can look at your child’s retina to see if there are signs of Usher syndrome.
- Hearing evaluation. During this test, an audiologist [aw-dee-OL-uh-jest] checks your hearing to see if you can hear high, low, quiet, and loud noises.
- Electronystagmogram [ee-LEK-troh-nai-STAG-moh-GRAM]. This test looks at eye movements you can’t control, which can be a sign that there is a balance problem.
Usher syndrome is a permanent, degenerative (gets worse over time) disease. However, there are steps that you and your doctor and other experts can take to help prepare children with Usher syndrome to live more independent lives. These can include:
- Hearing aids, unless the child is profoundly deaf
- Assistive listening devices
- Cochlear implants
- American Sign Language training
- Orientation and mobility training
- Communication services
- Braille training
- Low-vision services
Some doctors think that vitamin A can slow down the progress of retinitis pigmentosa, the condition that causes blindness in people with Usher syndrome. If your child has type 2 or type 3 Usher syndrome, you should talk to your doctor about whether vitamin A supplements might help slow down the disease.
While Usher syndrome can’t be prevented, you can talk to your doctor if you think that your child has this disease so that they can recommend treatment that might help your child deal with the symptoms throughout their life.
If you are thinking about having a child, you can talk to your doctor about the risk of passing on genetic diseases like Usher syndrome to your child.