Webinar: Usher syndrome mini series – part one
This webinar covers key questions and topic areas including what Usher syndrome is, how to get a diagnosis, both clinical and genetic, and what will happen after this.
Retinal degeneration can be one feature of a genetic condition that also affects other body systems. Certain genetic faults that cause damage to the eye can also impact other organs and tissues. Where more than one body system is involved, the condition is called a syndrome. However, the sight loss aspect can be very similar to that experienced by people living with non-syndromic retinitis pigmentosa.
There are three different clinical types of Usher syndrome, type 1, type 2, and type 3.
Symptoms
Hearing loss is the first symptom to become apparent, usually from birth. 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.
People with Usher type 1 develop profound deafness from birth and sight loss becomes evident in early childhood. The deafness is generally so early in onset and so severe that hearing aids may not be of value, although cochlear implants may be beneficial. Balance is often affected in those with type 1 and can slow the development of sitting or walking.
People with Usher type 2 also experience early onset hearing loss but this is less severe than in type 1. Sight loss usually becomes apparent during the teenage years. Balance is generally not affected.
Usher type 3 is very rare and is generally found in people with their family origins in Finland. Hearing at birth is usually normal but is lost during late childhood and becomes worse over time, with sight beginning to deteriorate during adolescence.
Cause
The prevalence of Usher syndrome varies from country to country, but it is a rare condition affecting approximately 1 in 10,000 people. Usher syndrome occurs when there are mutations in genes that are important for the function of the photoreceptors in the retina and the sound-sensing “hair cells” in the cochlea, or inner ear.
So far, researchers have found 11 genes that are associated with the three main subtypes of the syndrome. Usher syndrome occurs equally in both genders and is always inherited in a recessive pattern, meaning that both a person’s copies of the gene must be faulty for the condition to occur. Read more about inheritance patterns.
Treatment
Current treatment focuses on helping an individual to adapt to hearing and vision loss and to maximising the vision and hearing that they do have. This includes the use of hearing aids, assistive listening devices, cochlear implants, mobility training, and low vision services. The wide range of assistive technologies available provides plenty of choice for users at all stages of sight and hearing loss and this technology has also removed many barriers to education and employment.
Researchers are exploring a number of approaches to treating sight loss in Usher syndrome and there are clinical trials underway. Usher syndrome gene therapy is quite challenging as the genes affected tend to be extremely large in size and difficult to deliver into cells.
However, a project funded by Retina UK has enabled early development of a method to safely deliver these larger genes. This requires further work before it can be tested in people. Other approaches include ‘silencing’ the faulty section of genetic code or editing the genetic code. Alternatively, a treatment that is designed to work regardless of the underlying genetic fault could work for sight loss in Usher syndrome. Such treatments include cell-based therapies and more traditional drugs.
Visit the Research News for updates.
For up to date information on current clinical trials, visit www.clinicaltrials.gov. Please note that this website is not regulated, even though it is hosted by a US government institution. If you are considering joining a trial found on clinicaltrials.gov, always discuss it with your usual ophthalmologist or family doctor first to ensure that it is legitimate. Please also note that participation in a genuine clinical trial will never require payment.
Most potential therapies are gene specific, so it’s essential that those living with Usher syndrome are offered genetic testing to allow them to make choices about future treatments and clinical trial participation.
Retina UK is occasionally approached by researchers and companies looking for our help in recruiting participants for studies or patient involvement initiatives, and we can pass on details of opportunities to people on our database who have expressed an interest in these activities and given their consent to be contacted. Anyone who is not already in touch with Retina UK can call 01280 821334 or email info@RetinaUK.org.uk so that we can add them to our database. It is helpful for us to have as much detail about the diagnosis as possible, including genetic diagnosis if available, as some opportunities are condition specific.
More information
The Retina UK Helpline provides information, support and signposting to people affected by inherited sight loss as well as healthcare and education professionals.
Contact 0300 111 4000 (9.30am – 9.30pm Mon to Fri) or Helpline@RetinaUK.org.uk.
Join our lived experience panel
If you would like to get involved in representing the inherited sight loss community through activities like focus groups, surveys and research projects, join our Experience Panel.
