This section is a compilation of answers to the questions most commonly asked about Usher syndrome. Just start by following one of the links below for detailed answers. If you can’t find the question you wanted to ask, don’t hesitate to contact us at

  1. What is Usher syndrome?

    Usher syndrome is a genetic condition that causes hearing loss, vision loss, and sometimes balance/vestibular problems. Usher syndrome is "recessive" which means that two of the same Usher genes must be inherited - one from the mother, one from the father - in order for the child to have Usher syndrome. Often, parents do not know that they are carriers of the Usher syndrome gene because there is no history of Usher syndrome in the family.

    When both parents are carriers of the same Usher gene, there is a 25% chance that their child will have Usher syndrome, a 50% chance that their child will be a carrier of the Usher gene, and a 25% chance that their child will neither be a carrier nor have Usher syndrome. If both parents have Usher syndrome caused by the same gene, all of their children will have Usher syndrome. Some families have two or more children with Usher syndrome.

    For more information about the genetics of Usher syndrome, you may view our USH Talk, "Genetics 101."

  2. How many types of Usher syndrome are there?

    There are three clinical types of Usher Syndrome:

    Type 1 – causes profound deafness, Vision loss cause by retinitis pigmentosa (RP) may be noticed before the age of 10. Poor balance from birth is often associated with Usher type 1, which causes delays in sitting and walking. Children with Usher type 1 who receive cochlear implants at an early age usually communicate using speech and lip-reading. Many adults with Usher 1 communicate with sign language and identify as a culturally Deaf and/or DeafBlind.

    Type 2 – causes a moderate hearing loss. RP may not become apparent until adolescence. Speech assisted by the use of lip-reading and hearing aids or cochlear implants will usually be their primary method of communication. Balance is not affected, therefore children with type 2 walk at the typical age of 10 to 14 months.

    Type 3 – is the rarest form of Usher syndrome. It occurs with higher frequency in individuals of Ashkenazi Jewish and Finnish heritage. Children usually have normal hearing and vision at birth, then develop hearing loss and RP in adolescence or later. Hearing can deteriorate steadily over ten or fifteen years. Some with type 3 also experience balance problems.

    There are at least eleven different genetic types of Usher syndrome. There are six different genes that cause Usher type 1, three that cause Usher type 2, and two that cause Usher type 3. DNA testing - usually with a simple blood test - is the only reliable way of determining the true genetic type.

    Recent breakthroughs in genetic testing are allowing for earlier diagnosis of all types of Usher syndrome.

  3. What is Usher Syndrome Type I?

    (For an overview of the science behind Usher syndrome type 1, review this article from the National Institutes of Health (NIH) National Center for Biotechnology Information (NCBI), last revised October 8, 2020.)

    Usher syndrome type 1 is a recessive genetic disease. This means that a child receives two copies of the same Usher 1 gene, one from each parent. There are five subtypes of Usher 1: type 1B, type 1C, type 1D, type 1F and type 1G.

    Children with Usher type 1 are usually born profoundly deaf and experience progressive vision loss due to a retinal disease called retinitis pigmentosa (RP). The symptoms of RP first manifest as difficulty seeing in dimly lit areas - or night blindness - and a gradual loss of peripheral vision (tunnel vision). These symptoms will generally be noticed before the age of 10 and continue through adulthood.

    Children and adults with Usher type 1 usually have vestibular issues that affect balance. Balance issues manifest early in children with Usher type 1. The result is that they learn to sit up and walk later than their peers. Balance problems can become more pronounced as visual fields decrease.

    With the availability of genetic testing, Usher syndrome can be diagnosed in infancy. Prior to genetic testing, a diagnosis wasn’t usually made until one's 20s, 30s or 40s, when the vision loss from RP became severe enough to affect communication, socialization, daily living, and travel. Genetic testing - usually through a simple blood test - is the only way to definitively diagnose Usher syndrome.

    Carriers of Usher Type I
    Usher syndrome occurs when an individual inherits two copies of the same type of Usher 1 gene - one from each parent. If an individual has one Usher type I gene and one gene that is not Usher, they are considered to be a "carrier" of the Usher gene. Carriers have typical vision, hearing and balance. If two carriers of the same gene have a child, there is a 25% chance in each pregnancy that their child will inherit two Usher genes - one from each parent - and that child will have Usher syndrome. If a child inherits one Usher 1 gene and one non-Usher 1 gene, that child will be a carrier, like their parents. He or she will have typical vision, hearing, and balance. It is also possible that a child of 2 carriers will inherit 2 non-Usher syndrome genes, which means that they will not have Usher syndrome and they will not be a carrier.

    Hearing in Type I
    Hearing loss in children with Usher syndrome type 1 is usually severe to profound and present at birth.

    Vision in Type I
    A person with Usher 1 may become legally blind as a young adult primarily because of severe tunnel vision. Central vision is usually retained into adulthood, allowing individuals to continue to read print and use a computer. Some adults with Usher 1 will lose central vision more quickly, retaining only light perception.

    Balance in Type I
    Individuals with Usher type 1 often have limited vestibular functionality. This can result in severe balance issues. Children with Usher type I are often late sitters or late walkers. It is not uncommon for children with type I Usher to begin walking at 24-36 months. These balance issues are present throughout life and often become more pronounced in low light or as the vision degrades.

    Physical and occupational therapy can help individuals with type I with their balance issues. Core strengthening and hippotherapy can improve a person's ability to compensate for the decreased vestibular functionality. Mobility training can also be also helpful.

    Genes involved in Type I
    Usher syndrome type I is the most severe form of Usher syndrome and is characterized by congenital, profound, sensorineural hearing loss; vestibular dysfunction, often manifested as delayed walking (>18 months); and the onset of RP by the age of ten (Keats and Lentz, 2006). Usher syndrome type I is further subdivided into 5 types. Mutations in the MYO7A, USH1C, CDH23, PCDH15, and USH1G (SANS) genes cause Usher syndrome type 1B, type 1C, type 1D, type 1F and type 1G respectively.

    Mutations in these genes account for most cases of Usher syndrome Type I. Mutations in MYO7A are the most common accounting for 39-55% of cases (Keats and Lentz, 2006). An Ashkenazi Jewish founder mutation, R245X, has been identified the PCDH15 gene which has a carrier frequency of up to 2.5% in this population. MYO7A, USH1C, CDH23, and PCDH15 mutations have also been reported in several families with recessive nonsyndromic hearing loss. In addition, a few families with autosomal dominant nonsyndromic hearing loss (DFNA11) have also been described with mutations in MYO7A.

    Although these are the most common characteristics of Usher syndrome due to mutations in these genes, there can be variations. Overlapping and atypical presentations have been described for all three types of Usher syndrome. For example, some individuals with mutations in type I genes may have a milder presentation (moderate hearing loss and/or a normal vestibular system). In addition, certain genes (MYO7A, USH1C, CDH23, PCDH15, and DFNB31) can cause isolated hearing loss without developing retinitis pigmentosa.

    Identified disease-causing mutations in all of these genes include missense, nonsense, frameshift, splice-site as well as deletions distributed across nearly all exons.

    Usher Type I subtypes
    Although all individuals with Usher type 1 demonstrate similar symptoms, the genetic causes differ. Some are more common than others. Usher subtype 1b is by far the most common form of Usher type 1 and accounts for over 40% of all cases. Subtype 1d appears to be next most common and is responsible for about 25% of all cases. Usher Ic is not very common in the general USA population, but it is common among French Acadians in Louisiana. Usher 1f and 1g are uncommon and so far only a few cases have been reported. There is a form of Usher 1f that is common among people with Ashkenazi Jewish ancestry. Usher 1a does not exist and 1e is quite rare. There is evidence that there are more Usher 1 subtypes that have not yet been identified.

  4. What is Usher Syndrome Type 2?

    [For an overview of the science behind Usher syndrome type 2, review this article from the National Institutes of Health (NIH) National Center for Biotechnology Information (NCBI), last revised October 8, 2020 or review this article from the Online Mendelian Inheritance in Man website.]

    Individuals with Usher type 2 are born hard-of-hearing and gradually lose their vision due to retinitis pigmentosa (also known as RP). Hearing tests show a sloping hearing loss that is mild to moderate in the low frequencies and severe to profound in the high frequencies. Vestibular problems are absent in type 2, which distinguishes it from type I. RP generally manifests in the teen years and progresses throughout life.

    Today, most diagnoses are made before adulthood, but older people still report that the diagnosis wasn’t made until later in life when the RP became severe enough to interfere with their mobility.

    Carriers of Usher Type 2
    When an individual has one Usher 2 gene (carrier), half the normal amount of the protein usherin is produced. Scientists believe that this is sufficient for normal vision and hearing, therefore no observable symptoms result. There are theoretical reasons to think that there may be very mild hearing and vision problems in older adults who are carriers, but this has never been studied. It may be that these genes are partly responsible for some of the hearing and vision losses that all of us have as we grow older.

    Hearing in Type 2
    People with Usher type 2 are born with a moderate to severe hearing loss. The hearing loss is milder in the low frequencies and more severe in the higher one. Since most speech involves the lower frequencies, this means that adults and children with Usher type 2 will usually have good oral communication skills.

    Vision in Type 2
    A person with Usher 2 may become legally blind as a young adult primarily because of severe tunnel vision. While most adults retain good central vision for most of their lives, some with Usher 2 will lose their functional vision as they age.

    Balance in Type 2
    Individuals with Usher type 2 rarely experience balance issues.

    Genes involved in Type 2
    There are three subtypes of type 2 which have known gene locations: USH2A, GPR98 (VLGR1)and DFNB31 (WHRN).

    USH2A accounts for approximately 80%, GPR98 (VLGR1) accounts for approximately 15%, and DFNB31 accounts for approximately 5% of type 2 cases. DFNB31 mutations have also been reported in several families with recessive nonsyndromic hearing loss. Identified disease-causing mutations in all of these genes include missense, nonsense, frameshift, splice-site as well as deletions distributed across nearly all exons.

    Some mutations in USH2A can cause retinitis pigmentosa without hearing loss.

    Usher Type 2 subtypes
    Subtype 2c appears to be uncommon. Because the genes for 2b and 2d have not been identified, we don’t have any idea about their frequencies, but we believe them to be uncommon. There is evidence that there are more Usher 2 subtypes that have not been recognized.

  5. What is Usher Syndrome Type 3?

    Usher syndrome type 3 is is the rarest form of Usher syndrome, characterized by later onset hearing loss, RP that manifests between the second and fourth decades of life and variable vestibular dysfunction. Forty-two percent of those with Usher syndrome in Finland are thought to have USH3. It is also found in individuals of Ashkenazi Jewish heritage.

    Hearing in Type 3
    Individuals are born with normal hearing. Hearing loss begins during late childhood or adolescence and progresses to profound hearing loss.

    Vision in Type 3
    Children born with Usher type 3 have retinitis pigmentosa (RP) that manifests in later childhood or early adolescence.

    Vestibular Function in Type 3
    Vestibular (balance) function is typical at birth and may become affected in some with Usher 3 in adult years.

    Genes involved in Type III
    To date, only mutations in the CLRN1 (USH3A) and HARS (USH3B) genes are known to cause this type of Usher syndrome. Identified disease causing mutations in these genes include missense, nonsense, frameshift, splice-site as well as deletions distributed across nearly all exons.

  6. What is Retinitis Pigmentosa?

    How Retinitis Pigmentosa Works
    Retinitis pigmentosa (RP) is a disease of the retina cells in the eye that are known as the rods. The retina is the light sensitive tissue of the back of the eye where the first stage of “seeing” take place. With RP the retina slowly degenerates and loses its ability to transmit pictures to the brain. The early symptoms of RP include difficulty seeing in the dark, often coupled with problems in adapting to bright light and changing light conditions. A later symptom is a loss of ability to see to the periphery, also called tunnel vision.

    Rods are located in the retina and are mainly responsible for our ability to see dim light. Also, because they are located in the periphery of the retina, they help in peripheral vision. Because it is genetic, RP is actually present at birth, but it does not become detectable until later.

    Night blindness
    This refers to the inability to see in dim light. During twilight or at night, people with RP will have a great difficulty in seeing. In fact, a child who might see perfectly well during the day may be blind once the sun goes down. The first symptom is usually difficulty in situations where the level of light is low, like a movie theater. This is often present at an early age. Children with RP are sometimes reluctant to go out at night and may insist on a light during the night when sleeping. They may have difficulty in going from bright to dark lighting.

    Tunnel Vision
    In RP the cells at the edge of the retina gradually stop sending information about changes in light levels and the shape of objects on the edge of someone’s vision. This loss of visual field, or “tunnel vision” means that someone cannot see objects unless they are directly in front of him. This may mean for example, that they can still read books and a computer screen, but will need help to keep from running into things and tripping over low obstacles. As the RP progresses their ability to see out toward the sides and the top and bottom of their visual field decreases. The peripheral vision gradually decreases until they have a severe tunnel vision as adults

    Follow this link to get answers to common questions about RP from the Foundation Fighting Blindness.

  7. What causes Usher syndrome?

    Usher syndrome is inherited, which means that it is passed from parents to their children through genes. Genes are located in almost every cell of the body. Genes contain instructions that tell cells what to do. Each person inherits two copies of each gene, one from each parent. Sometimes genes are altered, or mutated. Mutated genes may cause cells to act differently than expected.

    Usher syndrome is inherited as an autosomal recessive trait. The term autosomal means that the mutated gene is not located on either of the chromosomes that determine a person's sex; in other words, both males and females can have the disorder and can pass along the disorder to a child. The word recessive means that to have Usher syndrome, an individual must receive a mutated form of the Usher syndrome gene from each parent. If a child has a mutation in one Usher syndrome gene but the other gene is normal, he or she is predicted to have normal vision and hearing. Individuals with a mutation in a gene that can cause an autosomal recessive disorder are called carriers, because they “carry” the gene with a mutation but show no symptoms of the disorder. If both parents are carriers of a mutated gene for Usher syndrome, they will have a one-in-four chance of having a child with Usher syndrome with each birth.

    Usually, parents who have typical hearing and vision do not know if they are carriers of an Usher syndrome gene mutation.

    This content was generously provided by the National Institutes of Health. For more on Usher Syndrome from the NIH, please visit their website.

  8. Does Usher syndrome always result in total blindness?

    Very few people with Usher syndrome will become totally blind – that is, have no light perception. Some adults maintain a small degree of central vision throughout their lives while others lose all usable vision. Natural history studies are currently collecting data to map the "typical" progression of vision, hearing and vestibular loss for the various types of Usher syndrome.

    Children will begin to develop night blindness in dimly lit areas. Progressive loss of visual fields will affect their ability to see to their right, left, above and below. Typically, central vision for reading and fine detail is functional into the adult years, as long as good lighting is available. It may take a minute or so for individuals with RP to adjust to glare and dramatic changes in lighting. As visual fields narrow, individuals with RP will often stop and scan the environment before entering a building or room. Objects and people at a distance will be easier to discern than those that are near to them.

    Sometimes children and adults with Usher appear to be clumsy because of vestibular/balance issues. This can be even more noticeable as visual fields decrease, or in dimly lit areas. Depth perception may be affected, as well as the ability to see monotones such as grey, white and black.

    Low vision specialists can suggest optical aids and devices that maximize remaining vision. Orientation and mobility instructors can provide training in safe travel.

  9. Why is early diagnosis important?

    Early diagnosis is critical for children with Usher syndrome. While there is no definitive cure for Usher syndrome, there are a LOT of treatments. There are treatments for hearing loss, treatments for balance issues, and, yes, treatments for vision loss. And many of these treatments are most successful when begun very early in life.

    In short, there is something that can be done. Lots of somethings. But you need a definitive diagnosis and you need it as early as possible. Here are just some of the reasons why early diagnosis is a good thing for a family:

    Communication Skills
    Kids with Usher syndrome have hearing loss. Regardless of the communication method a family chooses, be it sign language or oral communication, early detection is the key. Most language is developed in the first five years of life. You need to get started right away and knowing whether you’re dealing with Usher needs to be part of the decision process.

    Safety Concerns
    A child with hearing loss does not need mobility training, but a child with Usher syndrome might. Many parents of children with Usher report suspecting that their child had problems seeing at night, but they often only recognize it after an accident has occurred.

    Balance is also a concern in families with Usher. Riding a bike, ice skating or simply hiking a steep trail requires different preparation, skills and awareness for kids with Usher. Parents and kids can get creative and plan ahead when they have a diagnosis.

    Educational Support Planning
    Families that have a child with undiagnosed Usher syndrome may only consider supports for hearing loss as part of the Individualized Education Plan (IEP). Early diagnosis of Usher can change that before visual struggles start to appear. Vision loss changes the way a child learns. For example, a child with night vision problems might need a high contrast or tactile diagram of the night sky for an astronomy class. Those types of visual accommodations need to be part of a child’s IEP.

    Future Clinical Trials
    There are treatments nearing or in clinical trial that hold the hope of slowing, stopping, or even reversing the vision loss associated with Usher syndrome. But almost all of these treatments are diagnosis specific. In other words, it’s not enough to suspect Usher syndrome. You have to know definitively and you have to know the specific genetic cause.

    Family Planning
    Many families of children with hearing loss ask the question “will my next child have hearing loss, too?” Usher syndrome is an autosomal recessive genetic disorder. Each child born to carrier parents has a 25% chance of having Usher syndrome. A definitive diagnosis of Usher syndrome will assist parents who are planning to expand their family to make an informed decision.

    Satisfies the Need to Know
    Knowing removes the doubt. There are thousands of adults with Usher syndrome living happy, productive lives. Knowing this gives families a chance to support their child to take control of their own lives, to find positive adult role models with Usher syndrome, and to envision a future that is vibrant and bright.

  10. How does basic genetics apply to Usher syndrome?
    How does basic genetics apply to Usher syndrome?

    All of the genes in our bodies are made of a chemical called DNA (deoxyribonucleic acid). DNA is a chemical made of four kinds of building blocks, or bases: adenine (A), cytosine (C), guanine (G), and thymidine (T). These bases can be strung together in many different combinations to create unique DNA sequences. Genes are made of these sequences and contain the instructions for life. A small part of a gene might have a DNA sequence that looks like this:


    In total, humans have about 100,000 different genes that are grouped into small structures called chromosomes. People have 23 pairs of chromosomes, including a pair of sex chromosomes. Each pair consists of one chromosome that is inherited from the mother and another chromosome that is inherited from the father. The sex chromosomes contain genes that determine the sex of a person. Girls inherit two X chromosomes, whereas boys receive one X chromosome and one Y chromosome.

    Because people have two versions, or copies, of every chromosome, they therefore have two copies of every gene. The DNA sequences of these genes are more or less the same in everyone. However, sometimes there is a difference in one person's gene sequence as compared to the majority of the population. This DNA change is called an alteration, or mutation. Some mutations may occur that do not interfere with the health of an individual. Other mutations disrupt the gene enough so it does not function correctly. Below is an example of a mutation in a gene associated with hearing. The base change from G to T is enough to alter the instructions contained in the DNA sequence.

    ... A G A T G A G C A ... Normal sequence = Working gene
    ... A G A T T A G C A ... Mutated sequence = Non-working gene

    Gene mutations can be dominant or recessive. The Usher syndrome mutation is recessive. In this case, the altered gene is not strong enough to have an affect if a person also has one unaltered gene. As a result, an individual must inherit two altered genes, one from each parent, in order to be affected. The term carrier is used to describe a person who has one unaltered gene and one gene with a recessive mutation. This person is not affected but can pass on that mutation to his or her children. Because many Usher syndrome parents are carriers, Usher syndrome often appears in families with no history of Usher syndrome.

  11. What is a genetic test?

    A genetic test determines the DNA sequence of a certain region of the human genome. This region could be a whole gene, a portion of a gene, or other areas thought to regulate genes. The test will look for certain changes in the sequence that are known to have consequences on the function of a gene. These tests can be used to:

    1. diagnose a disease or other trait,
    2. determine if a person is a carrier of a mutation that could lead to disease in their children, and
    3. predict if a disease or trait that is not yet detectable by other medical tests may occur in the future.
  12. How are genetic tests performed?

    Most genetic tests are performed on a DNA sample. Because every tissue in the body is made of cells that contain DNA, any tissue can be used as a source of DNA. However, blood is the most common source because it can easily be obtained in large quantities; typically 5-10 ml (1-2 teaspoons) are taken for a test. Some laboratories will allow cheek cells to be submitted for genetic testing. In this case, the cells are usually collected by rubbing the inside of the mouth with a small brush.

    After the DNA is obtained from a blood or other tissue sample, a variety of different methods can be used to look for mutations in your genes. Sometimes the whole coding sequence of the gene is examined. This is similar to reading a page in a book to look for spelling errors in all of the words. Other times, methods are used that only look for the most common mutations. In this case, the test is similar to looking at a page only for a specific misspelled word and ignoring all of the other words. Some laboratories may combine these methods by first screening for common mutations and then, in certain circumstances, examining the whole coding sequence of the gene. Different laboratories may test for a different number of Usher genes.

  13. Why is genetic testing helpful?

    If you are visiting this website, chances are you suspect that you or a family member has Usher syndrome. The only way to know for sure is through genetic testing. Knowing can lead to improved decisions about treatment and management. In addition, genetic testing can help determine if other problems related to Usher syndrome besides hearing loss may be present or may develop in the future.

    In addition to improved treatment choices, genetic information may help in other ways. Genetic testing can provide an individual or the parents of a child with the satisfaction of understanding the cause of certain physical issues. It can also be useful when making reproductive choices because once a genetic cause is identified, it is then possible to predict the likelihood that future children of that person will also have Usher syndrome. In general, how people use genetic information will vary widely depending upon individual perspectives about hearing loss, religious beliefs, and other factors.

    Regardless of how the genetic information is used it can be an overwhelming and stressful experience for people to learn that a mutation in their own genes is the cause of their child's situation. It should be remembered, however, that genetic mutations are very common. All people carry gene mutations that might affect their health or physical characteristics. Mutations in some genes may cause medically important conditions, while others explain many of the normal differences between people. No person is responsible for the particular genes he or she possesses.

    These benefits and drawbacks of genetic testing must be understood by anyone considering testing so that an informed decision about testing can be made. Genetic counselors are skilled in educating others about genetic testing and its many associated issues. You should feel free to contact a counselor or doctor if there is any information about genetic testing that is unclear, or if you would like to discuss your particular situation.

  14. How does a child inherit a recessive mutation?
    How does a child inherit a recessive mutation?

    Children receive one copy of each chromosome from their mother (shown in green) and one copy from their father (shown in blue). In this image, a red band represents a recessive mutation in a gene on one copy of the father’s chromosomes and a second red band represents a recessive mutation in the same gene on one copy of the mother’s chromosomes. Each child has a 50% chance of receiving the copy with the recessive mutation from either parent. But, in the case of recessive mutations, both copies need to be altered for an individual to be affected. The chance of two events happening at the same time can be found by multiplying the chance of the two separate events together.

    (chance of receiving mutation from father) x 1/2
    (chance of receiving mutation from mother) x 1/2
    = (chance of receiving two mutations) 1/4

    Therefore, in each pregnancy, there is a 25% chance that the child will inherit both mutations and, on average, 1 out of 4 children will be have Usher syndrome.

  15. How are the results of an Usher gene test interpreted?

    There are four possible outcomes to an Usher gene test:

    No mutations are detected:
    If no mutations are found, and the entire coding sequence was analyzed in a gene, it is unlikely that the hearing loss is caused by mutations in that specific gene. However, the patient may have Usher syndrome due to mutations in another gene that causes Usher syndrome. Not all genes for Usher syndrome have been identified.

    Two mutations are detected:
    If two identical mutations or two different mutations in the same gene are found, and these mutations have been previously found to cause Usher syndrome, it can be assumed that the hearing loss is caused by these mutations.

    Only one mutation is detected:
    If only one mutation is detected, interpretation can be difficult.

    • It is possible that the test did not detect the second mutation. Even though examining the whole coding sequence of the gene will detect most mutations, there are other regions of the gene sequence and surrounding DNA that could contain a mutation. Unfortunately, these sequences are rarely analyzed unless a specific mutation is already known.
    • The mutation that was found may be unrelated to the hearing loss.
    Mutations were detected but their significance is unknown:
    Some changes in these genes are not considered to affect the function of the gene. These changes are often called “polymorphisms”. Sometimes, a new mutation is found and it is not yet clear whether the change will cause hearing loss or not. Unfortunately, more studies would need to be done before a definite conclusion could be made.

  16. How much does a genetic test cost?

    The cost and turn-around-time of a genetic test may vary depending on the lab and the methods used for testing. Some Usher screens cost around $500. More accurate and detailed testing may cost between $2000-$5000. A typical range of time to get the results might be 8-12 weeks. Insurance companies will often pay for genetic tests, but you should check with your company before your doctor orders the test.

    Individuals living in the United States who suspect they have Usher syndrome may be eligible for free genetic testing through the: Open Access Genetic Testing Program

    When you receive your results, please be sure to update your USH Trust Registry.

  17. What are the research areas into potential treatments?

    Research into effective treatments for Usher syndrome is focused on four main areas: gene therapy, retinal implants, stem cell therapy, and drug-based therapy. For the latest news on these and other research, Science News.

    For research updates organized by subtype, go to: Progress in Research to Treat Usher Syndrome

    Gene Therapy
    In 2008, researchers at the University of Pennsylvania and Children’s Hospital of Philadelphia used gene therapy to safely restore vision in three young adults with Leber’s Congenital Amaurosis (LCA), a rare and severe form of congenital blindness. According to Albert Maguire, ophthalmologist at the University of Pennsylvania, “Patients’ vision improved from detecting hand movements to reading lines on an eye chart.” One year later, the patients continue to enjoy the same level of improved vision, and the clinical trials have been expanded to include new patients. For more on this topic, click here.

    Many genetic diseases, including Usher syndrome, are caused by a spectrum of different mutations that include a type of mutation called a nonsense mutation. PTC Therapeutics has produced a drug, initially known as PTC 124, now called Ataluren, that has been successful in clinical trials for a subset of patients with Duchenne Muscular Dystrophy and Cystic Fibrosis, who harbor a nonsense mutation. These two diseases have initially been targeted due to their reasonably large patient populations, however, Ataluren may be effective in treating other diseases in which a subset of patients harbor nonsense mutations. A lab in Germany is testing the drug in a mouse model for one of the mutations that can cause Usher 1C via direct administration to retinal cells. For more on this topic, click here.

    Usher syndrome 1f is another type of Usher syndrome in which a subset of patients harbors a nonsense mutation. One particular mutation runs in Ashkenazi Jews. Researchers at the Technion in Israel discovered that, like Ataluren, a class of antibiotics, aminoglycosides, can counteract nonsense mutations. Gentamicin is an aminoglycoside. However, continued use of gentamicin is not feasible as, at the constant daily doses that would be required, it would be toxic to humans. Dr. Tamar Ben-Yoseph, a geneticist at the Technion who specializes in Usher Syndrome, collaborated with Professor Timor Baasov of the Chemistry department to modify aminoglycosides to make them safe for humans. The result was NB54, a derivative of gentamicin. The team has been testing NB54 in the lab and is working to obtain an animal model for the next phase of testing. For more on this topic, click here.

    Retinal Implants
    The U.S. Department of Energy is funding through 2010, and possibly beyond, the development of an artificial retina. The implant is a collaborative effort between the U.S. government, private industry and research universities. Clinical trials are underway for a 16 and 60 electrode version, The Argus I and II respectively, and development of the next generation with even more electrodes is underway. The implant works similarly to a cochlear implant, with a small camera mounted on glasses that sends a signal to the electrode array implanted on the retina. For more on this topic, click here and here.

    Researchers at the Massachusetts Institute of Technology are working a retinal implant that works similarly to the Argus implant with glasses and a camera. The chip will be implanted outside of the retina with only the electrodes attached to the retina. MIT hopes to begin clinical trials in three years. For more on this topic, click here.

    Click here to learn about other countries and teams also researching retinal implants.

    Stem Cell Therapy

    Several researchers are working to use stem cells to create new retinal cells to replace damaged ones. At SUNY Upstate Medical University in Syracuse, N.Y., researchers were able to convert frog stem cells into retinal cells. These cells developed into functioning eyes, enabling the tadpoles to see. For more on this topic, click here.

    Researchers at the University of Washington in Seattle are working to use stem cells to replace damaged retinal cells. They have succeeded in creating retinal cells from stem cells and are implanting these cells into blind animal models. For more on this topic, click here.

    Advanced Cell Technology (ACT) in Cambridge, MA, working with collaborators at Oregon Health and Science University, have created human embryonic stem cell (hESC)-derived retinal pigment epithelium (RPE). They have already implanted these cells into mouse and other animal models. Robert Lanza, Chief Scientific Officer at ACT, states that the company is preparing to apply to the FDA to begin clinical trials in humans. For more on this topic, click here.

    Using a type of skin cells known as human iPS cells, researchers at the University of Wisconsin-Madison School of Medicine and Public Health have successfully grown multiple types of retina cells, paving the way for repairing damaged retinas with new cells grown from the patient’s own skin. For more on this topic, click here.

    Drug-based Therapies
    Ciliary Neurotrophic Factor (CNTF) or NT-501 is a drug-based therapy from Neurotech. Using Encapsulated Cell Technology (ECT), surgeons deliver CNTF directly into the eye via implanted capsules. Phase 2 clinical trials for retinitis pigmentosa are complete. Several patients have experienced improved visual acuity following the implants. The FDA has fast tracked CNTF, meaning that, once clinical trials are complete, the FDA will expedite review of the results. For more on this topic, click here.

    Researchers at the Schepens Eye Research Institute in Boston discovered which chemicals in the eye, glutamate and aminoadipate, cause other cells to transform into retinal progenitor cells. These cells are similar to stem cells and regenerate new retinal cells. Testing in the lab and in mice showed that the cells became progenitor cells, migrated to the correct locations in the retinas, and developed into new retinal cells. For more on this topic, click here.

  18. What hearing changes can occur?

    Many people with Usher syndrome are born profoundly deaf. People with profound hearing loss often get little benefit from hearing aids. Those that choose cochlear implants have very little degradation in hearing as they age since cochlear implant bypass the hair cells in the cochlear.

    The most common genetic cause of Usher syndrome, Usher Type 2a, often causes moderate to severe hearing loss at birth. Like all people, those with Usher syndrome often experience a degradation in hearing as they age. Those that may have benefited from hearing aids may find the benefit wanes as they age. Some chose to have cochlear implants to compensate for the loss. Studies show that the majority of people with Usher syndrome experience a similar rate of hearing loss with age as the general population. However, a small percentage of people with Usher Type 2 may experience a faster rate of age-related hearing loss.

    People with Usher Type 3 often have normal hearing or a mild loss that deteriorates throughout life. By the third decade of life, most people with Usher Type 3 have hearing loss that is similar to all other types of Usher syndrome.

    People with Usher syndrome often greatly benefit from hearing interventions such as hearing aids and cochlear implants.

    Boys Town National Research Hospital maintains an excellent site that describes hearing loss in children. It is also applicable to adults.

  19. Some genetic conditions occur more frequently among people whose ancestors are from specific geographic locations or religious/cultural groups. Due to either intermarriage or a small gene pool, there is a higher chance that specific genes common to this group will be passed on, including genes which cause specific conditions such as Usher syndrome. Because of this phenomena, Usher syndrome may be more frequently seen in the following ethnic groups:

    Ashkenazi Jews - Usher 1f and Usher 3a are currently on the Ashkenazi Jewish genetic panel of 19 diseases for which Jewish couples should be tested if they are planning to have a family. Testing can determine whether individuals are carriers of these genes. If both parents are carriers of the same gene for Usher syndrome, there is a 25% chance of having a child with Usher syndrome in each pregnancy; a 50% chance that their child will inherit one Usher syndrome gene (and therefore be a carrier for Usher syndrome) and a 25% chance that the child will not inherit an Usher gene (will not be affected and will not be a carrier). Learn more about Usher 1f and Usher 3a.

    Acadian/French ancestry - Usher 1C is more prevalent in those of French heritage. Individuals with Usher syndrome 1c and carriers of the USH 1c gene migrated to Canada and Louisiana in the United States. Louisiana has a large USH1C community in and around the Lafayette area. Some families have multiple generations of individuals with Usher syndrome.

    Finnish Heritage - according to one study, Usher 3A accounts for up to 40% of all Usher syndrome in Finland

    Usher 1C - French, French Canadian or Acadian heritage
    Usher 1F - Ashkenazi (European) Jewish heritage
    USH 3A - Ashkenazi (European) Jewish heritage and Finnish heritage
    USH 3B - Amish heritage and anecdotal connection to India

    For more information on the different types of Usher syndrome, click here.

  20. Glossary of Terms

    Terminology related to Usher syndrome, blindness, hearing loss, and genetics is explained or defined below.

  • Audiologist

    A person who specializes in testing hearing and hearing loss.

  • A person who has one typical, or unaltered version of a gene, and one version with a mutation. This person is not usually affected by the mutation, but is capable of passing it on.

  • Chromosome

    A structure containing many genes arranged on a long strand of DNA. Each person has 23 pairs of chromosome, including a pair of sex chromosomes.

  • Clinical geneticist

    A doctor who specializes in recognizing and treating patients with genetic diseases.

  • DNA

    Deoxyribonucleic acid. The chemical that makes up genes. It is composed of adenine (A), cytosine (C), guanine (G), and thymidine (T).

  • Gene

    A unique sequence of DNA that serves as a specific set of instructions in the body.

  • Hearing threshold

    The lowest level of sound that can be heard during a hearing test.

  • Hereditary

    Inherited; something that is passed from parent to child

  • Mutation

    A change in a gene sequence that often disrupts the function of the gene.

  • Mutation - Recessive

    A mutation in a gene that is not strong enough to make a person affected if the person also has a normal copy of the gene.

  • Ophthalmologist

    A doctor who specializes in studying eye diseases.

  • Otolaryngologist (ENT/ORL)

    A doctor who studies ear, nose and throat disorders.

  • Sensorineural hearing loss

    Hearing loss caused by problems in the inner ear.

  • Syndromic deafness

    Hearing loss that is associated with other medical problems.