Usher syndrome: types, symptoms, causes and support in the UK

Usher syndrome is an inherited genetic condition. Sense describes it as causing hearing loss, sight loss and balance problems, present from birth but often taking years for symptoms to appear, and usually diagnosed in older children or teenagers.

The sight loss is caused by retinitis pigmentosa (RP), a deterioration of the retina that causes progressive loss of peripheral vision, sometimes called tunnel vision, and night blindness. Retina UK explains that Usher syndrome occurs when there are mutations in genes important for the function of the photoreceptors in the retina and the sound-sensing hair cells in the inner ear. It has found 11 genes associated with the three main subtypes.

Deafblind UK says there are three main types but not everyone fits neatly into them, which can make diagnosis difficult; such cases are referred to as atypical. A UK clinical reference article says types 1 and 2 together account for 90 to 95% of cases, and that most cases of type 3 come from Finland.

Retina UK says 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.

The UK clinical reference article says loss of vision usually starts with night blindness, followed by loss of peripheral vision, and that some degree of tunnel vision can continue until quite late. It notes that the rate of loss of hearing and sight varies between individuals, even in the same family, and that Usher syndrome can lead to or present with psychiatric disturbances.

Retina UK says Usher syndrome occurs equally in both genders and is always inherited in a recessive pattern. Both of a person's copies of the gene must be faulty for the condition to occur, which means each parent usually carries one faulty copy without being affected. The UK clinical reference article says that if a child is born with the condition the risk of an affected sibling is 1 in 4, and that preimplantation genetic testing has been reported as successful for affected families.

Many treatment approaches are specific to a particular gene fault, so Retina UK says it is important that those affected are referred for genetic testing to access new treatments and clinical trial opportunities.

Usher syndrome is usually suspected when hearing loss and retinitis pigmentosa occur together. The UK clinical reference article says electroretinography (ERG) to detect retinitis pigmentosa and electronystagmography (ENG) to detect vestibular problems aid early detection, and that most people with retinitis pigmentosa and hearing loss probably have Usher type 1 or type 2.

Early diagnosis matters because it allows specialist educational and support planning. Retina UK describes diagnosis as both clinical and genetic, and says people with the condition should be referred for genetic testing. Sense says a GP is responsible for referring you to specialists including ophthalmologists and audiologists.

Retina UK says current treatment focuses on helping an individual to adapt to hearing and vision loss and maximising the vision and hearing they have, using hearing aids, assistive listening devices, cochlear implants, mobility training and low vision services. Researchers are exploring approaches to treating sight loss, including gene therapy, and clinical trials are underway.

The UK clinical reference article says all affected people will benefit from a multidisciplinary approach, including adjustment and career counselling, technology such as hearing aids or cochlear implants, orientation and mobility training, and communication services and independent living training. Deafblind UK recommends regular eye checks, which can also highlight complications such as cataracts, and UV protection from sunglasses.

Deafblind UK says that because sight and hearing change over time, people have to repeatedly adapt, developing and changing coping strategies as they go.

Sense says that after a diagnosis you should talk to your GP, who can refer you to specialists and to counselling, and that you can choose to register your sight loss (a Certificate of Vision Impairment in England and Wales) and your hearing loss. Registration is voluntary and can help with benefits such as help with NHS costs and public transport concessions. It also says an eye clinic liaison officer can give practical and emotional support, and that if you have a combined sight and hearing impairment you are entitled to an assessment under the deafblind guidance, which may lead to communicator guides, mobility training and assistive technology.

Retina UK says hearing loss is the first symptom to become apparent, usually from birth. Sight problems may not show until later: it says first signs of visual loss in type 1 start in early childhood, and the UK clinical reference article says children with type 1 usually have some problems with vision by about age 10, with night vision affected first.

The same article says poor balance in type 1 makes children slow to sit without support, and that they rarely learn to walk before 18 months. Sense has guidance for parents on what to tell a child who has been diagnosed with Usher syndrome.

On the NHS, hearing loss is investigated by audiology and sight loss by ophthalmology, with genetic services providing testing and counselling. A GP coordinates referral. Some people seek private genetic testing or a second opinion; if you do, ask how results will be shared with your NHS team and who will provide counselling.