What Is Usher Syndrome?
Usher syndrome is a genetic condition that gets transmitted in the family and affects hearing, vision, and balance. It is a common condition that causes deafness and blindness in children. In some patients, it may also affect the balance. The degree of hearing loss will vary from person to person; in some patients, it will be partial hearing loss, whereas, in some, it may be complete hearing loss. The vision problems are called retinitis pigmentosa. In this condition, the retina of the eye is affected, which is part of the eye that plays an important role in vision. In this condition, the retina of the eye is damaged slowly over time and can even lead to complete blindness.
What Are the Different Types of Usher Syndrome?
There are three types of Usher syndrome which affects the varying degree of hearing and vision loss, and they are:
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Type 1- Babies with Type1 Usher syndrome suffer from severe hearing loss or deafness. They start to have vision loss from around when they are ten years old and get worse with age. The vision loss starts as loss of vision at night and can worsen to cause complete vision loss over time. Also, the children suffering from type1 Usher syndrome do not start to walk till at least 18 months old.
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Type 2 - Babies with type 2 Usher syndrome are born with hearing loss. The hearing loss may be moderate to severe. These children do not suffer from balance-related problems. The vision gets affected when they are in their teenage years and get worse over age.
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Type 3- Type 3 Usher syndrome is rarely seen. The children suffering from this type of Usher syndrome are born with normal hearing and vision. Hearing loss begins to affect in late childhood time, and vision loss begins in early to mid-adulthood. The vision is affected initially as night blindness. Balance problems are seen only in half the population suffering from type 3 Usher Syndrome.
What Causes Usher Syndrome?
Usher syndrome is caused by a mutated gene and is passed on to children. For this condition to pass on to the next generation, both the parents need to be a carrier of the gene. With each pregnancy, the chance of having a child with Usher syndrome is one in four, that is, 25 %.
What Are the Symptoms of Usher Syndrome?
The symptoms of Usher syndrome will vary from person to person and will also vary according to the type of Usher syndrome the patient is having. The common symptoms of this condition are:
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Hearing Loss- Some children suffering from this condition will be completely deaf when they are born, and some others will experience only mild to moderate hearing loss that can worsen over the years. In some other groups of patients, the onset of hearing loss will be in their adulthood. The degree of hearing loss will depend on the type of Usher syndrome the child is suffering from.
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Vision Loss- The children with Usher syndrome have vision due to a condition called retinitis pigmentosa. This begins as difficulty in seeing in low light conditions (night blindness) and can worsen to cause complete blindness.
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Balance Problems- The patients with Usher syndrome also experience balance-related problems which are maintained by the inner ear. When there is damage to the inner ear, it can affect balance and coordination.
What Causes Vision Loss in Usher Syndrome?
In Usher syndrome, the part of the eye called the retina is affected. The retina is the tissue at the back of the eye and helps to see. The mutated gene affects the retina’s light-sensing cells called rods and cones. This condition is known as Retinitis pigmentosa. These rods and cones are affected slowly, resulting in night blindness. The damage usually starts from the sides and results in peripheral vision loss, which then moves to affect the central vision.
What Causes Hearing Loss in Usher Syndrome?
In Usher syndrome, the cells which transmit the sound are affected. The cochlea is a spiral structure present in the inner ear. When this is affected due to gene mutation, it cannot transmit sound effectively, and hence the patient will have hearing loss.
If you notice any hearing or vision problem in your child, get consulted by a specialist so that an early diagnosis can be made. The diagnosis of this condition is made by the following tests:
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Hearing Test- An otolaryngologist (a specialist in ear, nose, and throat-related problems) along with an audiologist (a specialist who deals with hearing problems) test the child’s hearing. They do tests that will check the child’s ability to hear a variety of sounds and frequencies.
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Vision Tests- An ophthalmologist will evaluate the child's vision. They do tests to see the damage to the retina. They will also do a test specific to retinitis pigmentosa, which is an electroretinogram (ERG). This test is done under general anesthesia. Electroretinogram is an evoked response from the cones and rods of the retina. This test checks the retina's response to light.
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Balance Tests- Electronystagmography is a test done to assess the balance of the patient. This test checks eye movements to check for balance problems.
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Genetic Testing- When Usher syndrome is diagnosed in a child, then a genetic test is done to get a definitive diagnosis as well as to know which type of Usher syndrome the child has. This is done by doing a blood test and looking for one of the nine genes that cause Usher syndrome.
How Is Usher Syndrome Treated?
Usher syndrome cannot be cured as of now. The treatment will depend upon the age, symptoms, and general health of the patient. The treatment involves ways to manage the symptoms and to improve the quality of life of people suffering from Usher Syndrome and is discussed below:
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Hearing Aids- Hearing aids will assist patients having mild to moderate hearing loss. This can be given to patients suffering from type 2 or 3 Usher syndrome patients.
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Cochlear Implants- This can be for patients with severe hearing loss. This will be helpful for patients suffering from type 1 Usher syndrome.
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Vision Aids- There are various options to cope with vision loss other than prescription glasses which will be useful for these patients.
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Orientation and Mobility Training- The orientation and mobility training will help these patients with balance-related problems to some extent.
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Speech Therapy- As these patients have hearing loss, there are chances that these patients will have chances of developing dumbness as a consequence of deafness. In such cases, a speech therapist will provide assistance in the condition.
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Vitamin A Supplements- There is evidence showing that taking vitamin A can delay the retinitis pigmentosa in Usher syndrome patients. Consult a doctor before taking these supplements, especially when you are pregnant.
Conclusion
Usher syndrome is a genetic condition that is inherited from the parents. These conditions affect hearing, vision, and balance in patients. When you see any signs of any of these symptoms in your child, get a consultation from a doctor as an early diagnosis will help to manage this condition in a better way. There are treatments developed to cure this condition now, but with the help of various aids and devices, patients with Usher syndrome can lead a normal life like everyone else.
