What is Usher syndrome?
Usher syndrome (USH) is a condition that causes hearing and vision loss. Some people also have problems with balance.
For normal vision, the retina acts like the film in a traditional camera. It is here where the pictures are created, then sent to the brain for interpretation.
The retina is made up of light-sensitive cells. There are two different types of cells – rods and cones.
Rods are good for seeing in the dark and seeing things in your side vision. Cones are the cells that are used for your sharp vision. They are good for seeing things in daylight, colour and fine detail.
When you have retinitis pigmentosa, rods and cones don’t work the way they are supposed to.
How common is USH?
Whilst USH is rare, inherited retinal diseases altogether affect around 1 in 4000 people or over 2 million people worldwide. They are the leading cause of blindness in working age adults.
What are the causes?
USH is a genetic condition.
Genes contain DNA, which is short for ‘deoxyribonucleic acid’. A gene has the instructions on how cells in our body grow and work.
USH is caused by a change in one or more genes. This results in vision and hearing loss.
Around 15 different genes are thought to cause USH. There are many more genes, but they haven’t been discovered yet.
A person with USH will have inherited a change in both USH genes – one from each parent. The parents of someone with USH often do not show signs of the condition. They typically have good vision and hearing. Often there is no history of USH in the family.
Parents who are closely related (e.g. cousins) may have a higher chance than unrelated parents to both carry the same gene causing USH.
What are the symptoms?
There are three clinical types of USH, but type 1 and type 2 are more common.
- Affects around 40 per cent of people with USH.
- There is profound deafness from birth, requiring cochlear implants. These devices are placed through surgery. They send sound directly from the ear to stimulate the hearing nerve.
- Balance problems. Affected children usually take longer to sit, stand and walk than a typically developing child.
- Difficulty seeing at night (night blindness) and side vision loss (tunnel vision) may occur in childhood to early teens.
- Affects around 60 per cent of people with USH.
- There is often moderate hearing loss from birth. Hearing aids are often needed.
- Night and side vision problems start to develop during teenage years and early twenties.
- Balance may be affected in later years.
Very few people go completely blind from USH. Central vision often remains.
How is USH diagnosed?
Diagnosis of USH usually involves testing hearing, vision and balance.
Therefore, diagnosis may require the coordinated efforts of several medical professionals. These include: paediatricians (specialists in childhood conditions), otolaryngologists and audiologists (specialists in ears and hearing), ophthalmologists (eye specialists) and allied health professionals.
To check your child’s eyes, an eye healthcare provider will do various eye tests, photographs and scans. This helps better understand their eye problem. Often you will be asked about your child’s general health and if anyone else in the family might have vision problems.
If you or your child are diagnosed with USH, it can be helpful to speak to a genetic counsellor. This may help you:
- understand what USH could mean for you and your family
- provide support to help you and your family adjust to living with the condition
- if you are thinking about starting or extending your family
- learn about any appropriate research studies or clinical trials.
Sometimes doctors cannot be certain which gene change is causing USH just by looking into the eye. Genetic testing may be suggested. This involves having a small blood or saliva sample collected and sent to a laboratory. Genetic testing could help find out the exact gene change causing USH in you or your child. However, it doesn’t always identify the gene change because many are still being discovered.
In Victoria, you can access specific genetic eye counselling through the Ocular Genetics Clinic at the Royal Victorian Eye and Ear Hospital or Genetic Eye Clinic at The Royal Children’s Hospital. If you live in another state, it is best to speak with your eye healthcare provider and local clinical genetic service.
What treatment is available?
The treatment of USH is directed toward managing the vision, hearing and balance problems associated with USH.
For most inherited retinal diseases – including USH – currently there is no potential medicine, surgery or ability to cure vision loss.
There is a lot of promising research into gene therapy and stem cell technology and upcoming clinical trials that are bringing hope to families.
It is possible to manage the vision, hearing and balance problems that occur in USH.
You can look after and maximise vision for you or your child through:
- regular eye checks, no matter the level of vision
- orientation and mobility training
- using low vision aids such as magnifiers and closed-circuit televisions
- using technology and applications (apps) on devices
- educational support at school or university
- wearing sunglasses
- extra lighting for help in dark environments
- not smoking
- having a healthy diet.
Managing hearing problems may involve cochlear implants, hearing aids, sign language (AUSLAN), adaptive technology and communication skills training.
Managing balance and coordination problems associated with USH may involve physiotherapy and occupational therapy programs. Speech-language therapy programs can also support people with USH.
You may find support groups and online patient communities helpful.
What research is happening at CERA?
CERA researchers are working on potential treatments for inherited retinal diseases. At the same time, they’re advancing scientific knowledge of the genes that cause these diseases.
- Principal Investigator Dr Tom Edwards is investigating a gene therapy for a specific inherited retinal disease.
- Professor Alex Hewitt (CERA) and Professor Alice Pébay (University of Melbourne) are using stem cell technology and gene-editing techniques to develop new treatments.
- Dr Raymond Wong is using cell reprogramming and stem cell technologies to understand how to replace lost retinal cells.
- CERA and the University of Melbourne are creating a national clinical database of people with inherited retinal diseases. The project aims to improve understanding of inherited retinal disease and find patients who are eligible for clinical trials.
- Associate Professor Penny Allen is leading the Bionic Eye Project at CERA. She is testing a bionic eye in people with retinitis pigmentosa.
How can I help?
You can support CERA’s research into USH by:
- making a donation
- volunteering for research or being informed about any upcoming clinical trials
- referring yourself or a patient to the national IRD database.