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Usher Syndrome – symptoms, diagnosis and treatment
What is Usher Syndrome?
Usher syndrome is a rare genetic, inherited condition affecting both hearing and vision. According to Sense, Usher syndrome affects between 4-7 people in 100,000 people worldwide. Damage to hearing causes deafness/hearing loss, whereas an eye disease called Retinitis Pigmentosa (RP) causes vision loss.
The Usher syndrome is not a disease that someone gets with time, people are born with it. Since it is genetic, it is passed on through genes. As this disease affects hearing, it also causes problems with balance for many people.
What causes Usher syndrome?
This syndrome is caused by mutation in specific genes. The research is still ongoing, however, so far, the below genes have been associated with this syndrome:
Type 1: MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2
Type 2: USH2A, ADGRV1, WHRN
Type 3: CLRN1, HARS1
The most common genes contributing towards type 1 and 2 are MYO7A and USH2A.
Usher’s syndrome affects both vision and hearing. The vision is affected as the gene mutation in this syndrome affects the rods and cone’s cells (light-sensitive cells). As these cells are affected, with time, they go bad, starting with blurring outer edges and only leaving the centre part (central vision) which eventually might lead to blindness.
The gene mutation affects the nerve cells in the spiral structure of the inner ear called the cochlea, stopping them from transmitting sound normally, causing hearing problems.
Types of Usher syndromes
There are three types of Usher syndrome, each type causes different degrees of hearing and vision loss. Type 1 and type 2 are most common, whereas type 3 is very rare.
People with Type 1 Usher syndrome are either born with deafness or have severe to profound hearing loss, making sight loss very evident in childhood. As a result, they might lose night vision by age 10, which worsens with time. Balance issues, such as problems in walking, sitting, or standing up are faced because of type 1 Usher syndrome. Most babies with this type will not start walking until 18 months because of affected balance.
People with type 2 Usher syndrome are born with moderate to severe hearing loss (however, less severe than type 1). Night vision loss starts in teenagers and slowly affects their vision with time. Children with this type of Usher syndrome do not face balance problems.
People with type 3 syndrome have normal hearing at birth which starts to decline in late childhood. Vision loss begins in early to mid-adulthood, which grows with age. About half of the people experience a problem with balance.
What are the symptoms of Usher syndrome?
Usher syndrome causes a condition called retinitis pigmentosa, a severe eye condition; this condition starts by affecting night vision and makes it hard for the person to see things when it’s dark or dim, causing loss of peripheral vision. This condition worsens with time, removing most of your side (peripheral) vision until you are left with a tiny bit of central vision. Most people suffering from retinitis pigmentosa will lose their sight with time.
This syndrome adversely damages the ears, causing hearing problems. For some people, this loss can be managed through hearing aids, others might lose their hearing capability completely. The hearing damage depends on what type of Usher syndrome the person is suffering from and the phase of diagnosis.
Because this syndrome damages the ear, it naturally affects the balance of the body, which can lead to problem in movements, such as sitting or walking.
Usually hearing loss is the first symptom to become apparent. Sight loss follows a similar pattern to non-syndromic retinitis pigmentosa; early symptoms include night blindness and reduced peripheral vision, with central vision loss occurring later.
How is Usher syndrome diagnosed?
This syndrome can usually be diagnosed in children or teenagers by running the below tests:
- Hearing test – type 1 and type 2 are usually picked up through a new-born screening, which is a series of health checks conducted on an infant to confirm their health status
- Sight test – this entails a series of tests such as:
- Colour vision test
- Visual field testing to check the peripheral vision loss
- Tomography and autofluorescence to assess the health of the retina
- Electroretinogram to assess the photoreceptors cells (to check response to light) to help diagnose retinitis pigmentosa
- Balance test – a range of tests are conducted to find the cause of balance problems such as assessing the eardrum movement, checking abnormality in eye movement through various approaches
- Genetic test – similar to any other genetic testing, this test is conducted through a blood test to diagnose the Usher syndrome
Can Usher syndrome be treated?
This syndrome can be managed with various options depending on the type, and how far along is the person with this condition. These technological treatment options help individuals to maximise their hearing and vision ability and remove the barriers to education and employment too.
- Hearing aids – this option is effective for those with mild to moderate hearing loss. It is specifically helpful for people suffering with type 2 and 3 of Usher syndrome as they develop hearing loss at a later stage of their life.
- Vision aid – vision loss can be treated with devices such as prescription glasses, lenses that filter light, reading prism and more. There are non-optical aids available such as text-reading software, braille readers and enlarged publications. These aids can talk or the text is magnified, to aid reading.
- Cochlear implants – an advanced device implanted to help in hearing when normal hearing aids are not effective. This implant consists of two parts – an implant placed in the inner ear, surgically and an external device which is worn on or near the ear. These two parts are connected with each other through a magnet. This treatment can be utilised by anyone but is most beneficial for those suffering with type 1 Usher syndrome.
- Vitamin A supplements – intake of vitamin A can help slow the development of RP in some people. However, too much Vitamin A can cause serious side effects. It’s best to consult your doctor before starting these supplements.
Can Usher syndrome be prevented?
Unfortunately, since this is a genetically inherited condition, it cannot be prevented. However, early diagnosis, and correct treatment can help patients to maximise their ability to hear and see. It is essential to keep an eye on your child’s day-to-day actions and consult your doctor if you’re not sure about anything. You should look out for the below in your children:
- Fast change in your child’s prescription
- Problem hearing/following any sound
- Issues in movement such as walking, sitting, or getting up
- Difficulty in balance or coordination
- If your child has started walking at a very late stage