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Usher Syndrome
Frequently Asked Questions (FAQs)
- What is Usher Syndrome?
- What are the symptoms?
- How is it transmitted?
- How quickly does it progress?
- What are the challenges for someone who has visual & auditory disability?
- How can family and friends help?
- Can it be treated?
- What can be done?
- How prevalent is Usher Syndrome?
- How can the diagnosis be handled better?
- How can education and career guidance help?
- Can counselling help?
What is Usher Syndrome?
Usher syndrome is an inherited condition which results inhearing loss and a progressive loss of vision from Retinitis Pigmentosa (RP). The hearing loss is thought to be congenital, and ranges from moderate to profound. RP can occur without hearing loss. The condition is named after a British ophthalmologist, C.H. Usher, who in a paper in 1914 described several cases in which the link between congenital deafness and RP was stressed. However, as far back as 1860 workers such as von Graef and Liebreich in Berlin were aware of the link between congenital deafness and RP, especially in consanguineous marriages. There are three known forms of Usher syndrome.
What is Usher Syndrome type 1?
Individuals with Usher syndrome type 1 are born profoundly (completely) deaf and experience problems with balance. In adolescence, they usually begin to exhibit the first signs of RP: night blindness and loss of peripheral vision.
What is Usher Syndrome type 2?
Individuals with Usher syndrome type 2 experience moderate to severe hearing impairment at birth, but they do not have balance problems and hearing loss is not progressive. Symptoms of RP develop later in adolescence.
What is Usher Syndrome type 3?
With Usher syndrome type 3, at birth there is no hearing or visual impairment. Hearing loss and vision loss due to RP develop in adolescence or early adulthood and both are progressive.
Researchers believe that the hearing loss in Usher syndrome is due to a problem with the sensory (nerve) cells in the cochlea, a structure within the inner ear that is necessary for transmission of sound to the brain.
What are the symptoms?
Night Blindness
The first symptom to appear in RP is night blindness; this may also be coupled with difficulty in adapting to bright light or rapidly changing light conditions. Difficulty with dark adaptation can occur in childhood, and although it may be noticed it is seldom attributed to RP, but rather clumsiness, stupidity or even lack of carrots!
Tunnel Vision
In one form of retinal degeneration the rod cells which lie on the periphery of the retina gradually lose function and fail to transmit information about changes in light levels and shapes of objects on the periphery. This loss of visual field or 'tunnel vision', as this is commonly known, means that the individual loses his or her ability to locate objects which are not directly in front, so that for instance, he may still be able to read the bus timetable but unable to locate the bus station without help.
Loss of Central Acuity
Another form of retinal degeneration causes the cone cells to be affected initially so that the individual can no longer see the details of the object in front of him and he will be unable to read print. This type of loss is referred to as macula degeneration and in this case low vision aids such as hand magnifiers and magnification of print using a closed circuit television screen as well as large print texts may be helpful.
In both forms of retinal degeneration the extent and speed at which vision deteriorates is extremely variable. In some individuals the breakdown of the retina is so marked that at the age of six they require special education for the visually impaired and are on the blind register.
Others may have noticed no severe restriction of vision until they reach their thirties and it is not uncommon for some to retain their reading vision well into old age.
For those with Usher Syndrome, the retinal condition tends to be diagnosed later in life and affected individuals may not know they have RP until they have reached young adulthood.
How is it transmitted?
Usher is transmitted genetically by an autosomal recessive gene. To produce a child with Usher both parents must carry the recessive gene. Autosomal implies that the gene is not sex linked and so both males and females are equally affected by the condition. In recessive inheritance both parents carry the gene, but are not aware that they are carriers until the condition is diagnosed in their children. The child with Usher syndrome has two recessive genes for the trait and will transmit these genes to their offspring.
If a person with Usher marries another with the same syndrome, all their children will be expected to have the same condition. If a person with Usher marries a person without the condition, the children will be unlikely to have the condition, but they will be carriers. If a person with Usher marries another deaf person, the latter should be tested to see if they have the condition, albeit mildly.
A child who is identified as being at high risk for Usher syndrome should be referred immediately to an ophthalmologic clinic which has the capacity for full diagnostic testing.
How quickly does it progress?
By the age of 20 most deaf people will be in training or already employed. Those who have RP may well be doing work which will eventually prove difficult or even dangerous to carry out.
The rate at which vision will degenerate over the third decade of life is difficult to predict, there is therefore a question about when to change course. Should the keen young motor mechanic and student nurse carry on, and have perhaps 10 to 15 satisfying years of work, or should they change to something that they can work at even when their vision has become severely restricted?
What are the challenges for someone who has visual & auditory disability?
"Most deaf people have a negative attitude towards blindness. For very understandable reasons deaf people universally feel the worst possible handicap that can befall a human being is blindness. Ironically, blind people feel the same way about deafness."
Vernon
Vernon's apt words embody the dilemma which affects those who are both deaf and blind. As the deaf person contemplates the future with RP he or she is already leaving the world of the deaf and entering the world of the blind, yet neither world wants to know him. Contrary to popular opinion, people with one disability are not predisposed to being sympathetic and understanding towards those with a different condition from their own.
Deaf people are largely dependent on sight to aid communication, as the visual field narrows it becomes more difficult for the affected person to follow signs and lip read more than one person. Young adulthood is the time to be out and about pursuing sports and leisure activities and socialising with friends. The young deaf person who also has RP will find that night blindness places severed limitations on their social life, on opportunities for meeting people and on developing friendships.
A deaf friend who, for some inexplicable reason, walks into lamp posts, trips over curb stones and needs to hang on to an arm is an embarrassment and liability to his friends. Thus, even before the diagnosis of RP is confirmed this young deaf person has begun to withdraw from social life an the pattern of isolation is being established.
Regrettably, in some cases RP is not diagnosed until a serious incident such as a road traffic accident suggests that the patient's vision should be examined more thoroughly. The victim not only has to face recovery from an accident but also the knowledge that he has an untreatable eye condition.
All these factors, social isolation, uncertainty about employment, the emotional reaction of parents and facing an unknown future make it hard for this young person to adjust. The youngster often faces these difficulties with little constructive help from the army of professionals who may be consulted, and they are fortunate if they find anyone who truly understands the condition of Usher Syndrome, who can offer the constructive counselling that will be needed over the ensuing months and years.
How can family and friends help?
A diagnosis of Usher Syndrome for the individual poses many problems and also for the family. The reaction of friends and relations can largely determine how the victim will handle the future and how well. Parents who have faced the first hurdle of deafness with their child, who have spent the growing years struggling with language, lip reading, speech development and hearing aids and learning sign language, together with the emotional output involved will begin to feel that this great effort has been rewarded as the young adult starts out in life. It is at this point, as the son or daughter becomes more outgoing, starts work, starts driving perhaps, or wants to get engaged that the awful truth is often discovered.
Reactions to the diagnosis of RP vary. Some parents are so shocked that they can hardly bring themselves to talk about it to each other. If the diagnosis is made when only one of the parents is present, he or she not only has to bear the initial shock, but also has the unenviable task of trying to convey the news to the spouse. The consultant may not have had enough time to explain in terms that the parent con comprehend the nature of Usher syndrome, and the stricken parent leaves the consulting room with many half formed questions till unanswered. It is often left to the parent to break the news to their child and many are at a loss as to how this should be done. They may not disclose the diagnosis immediately; some parents carry the burden of knowledge for months or even years only revealing the truth when their child is planning to marry or take a hazardous job.
Some families cannot accept the prognosis of possible blindness. The term 'blind' is an inadequate word because in lay terms it means someone who cannot see anything [In the same way the term ‘deaf’ can convey a meaning of total deafness whereas it is a term covering all degrees of hearing impairment]. Unless the nature of RP as a visual handicap is explained these parents take comfort in the knowledge that their son or daughter can see to read and ignore the fact that he or she may only have 25% of his central vision still functioning. This attitude can lead them to react inappropriately to the practical and emotional needs of the affected child.
An understandable reaction to the diagnosis of Usher is for the family to search for treatments. They may have been told kindly or otherwise by the consultant that there is at the moment no known cure for RP, yet they have read newspaper reports about treatment around the world which claim to arrest the condition. Sadly, many families spend the next vital years pursuing these claims, raising money and making big financial sacrifices in order to pay for travel and treatment yet the real need for rehabilitation, career guidance and help with daily living skills for the young person is neglected.
Can it be treated?
Although there is no known effective treatment for RP, the future is not without hope. Intensive research is under way across the world to discover the cause, prevention, and treatment of the vision loss with Usher syndrome. While not a cure, a specified dose of vitamin A has been found to slow the progression of RP in some individuals with typical RP and Usher syndrome type II. Contact your doctor, ophthalmologist or local member organization of Retina International for more information.
Research to precisely identify the specific genes involved in each Usher syndrome type is moving at a rapid pace. In the near future it should be possible to perform a test on genetic material from blood and other cells to determine if the specific gene defect causing Usher syndrome is present. When available, this testing will provide an accurate genetic diagnosis useful for early detection of the disorder, and for defining the risks of other family members or future offspring being affected.
Currently there is no way to halt the degeneration of the retina or to restore normal hearing. The hearing loss cannot be corrected with middle ear surgery. Some patients with severe hearing impairment have benefited from cochlear implants. Others with residual hearing may benefit from the use of hearing aids.
What can be done?
Early Diagnosis
The need for early diagnosis is essential if the traumatic effect of discovering this potentially blinding disease is to be reduced. However, this can only occur if the professionals who see the deaf-blind child during their school life are aware of Usher Syndrome and know what to look for. The major symptoms that should lead to an immediate referral are night blindness, extreme sensitivity to light and/or tunnel vision; also these children may have a problem with balance. The family doctor, the class teacher and the audiologist who see the deaf child regularly need to be aware that the congenitally deaf child is in a high risk group for Usher. Other professionals such as the ophthalmologist, the optician and the psychologist need information too, if early diagnosis is to be achieved.
How prevalent is Usher Syndrome?
It has proven difficult to establish accurate figures for the occurrence of Usher Syndrome. Figures for the incidence in Europe are incomplete; in the USA more statistical work has been done but even there the figures are tenuous. About 3 per 100,000 people in the US have Usher. Of all those who have a congenital hearing impairment, 3 to 6% are victims of Usher. Of the 70,000 to 100,000 population who have RP in the US, one out of four has Usher syndrome. Thus, Vernon estimates that there are 17,500 to 25,000 people who will be deaf-blind due to Usher syndrome. As Vernon rightly points out, these figures show that Usher syndrome is all too common among deaf people. Ignorance amongst professional people who deal with deaf children about this syndrome is widespread. This must change. The need for earlier diagnosis is paramount if benefit is to be had from educational guidance, career counselling, psychological coping techniques and genetic counselling.
How can the diagnosis be handled better?
While it is true that at present the medical professional can offer no effective treatment for RP, they can and should offer time, sympathetic handling and honesty to the people in their care. What goes on in the consulting room when the patient and his family are told about the diagnosis of Usher syndrome is critical to the way in which they will all handle the situation later. Too often the facts are given in a cold even brutal manner and the bewildered family is marshalled out of the room before they have time to think. If the deaf patient communicates by sign language and finger spelling and no communicator is present it is possible that he has only grasped half of the truth. If the parents are too upset to explain, the 'victim' is left in the highly unsatisfactory state of knowing something is badly wrong, but not knowing what. It is important that a sign language interpreter used to the medical terminology is made available at these appointments.
Much of this anguish can be avoided if the patient and the family are given a proper explanation of the condition and allowed time with the help of a communicator (if necessary) to ask questions and understand the implications of the disorder. The medical social worker should be involved to introduce the family to organisations, aids and benefits which may be needed in the future. It is very important at this stage that the individual and the family are given the support they need and not left to face the future 'as best they can'. It may help the newly diagnosed person and his family to be linked with a family who are handling the situation reasonably well, in order to talk about their concerns.
How can education and career guidance help?
If Usher is diagnosed before the young person has left school the teaching staff will need advice on handling the pupil with RP. Informing the school that the child has Usher syndrome is not enough, precise information about the field of vision, the extent of central loss and whether he needs protection from extraneous light will be required.
There are some Low Vision Aids such as magnifiers, binoculars and Closed Circuit Television which could benefit the student's visual performance and he should be referred to the Low Vision Aid Clinic at the nearest hospital for an assessment.
The class teacher will also need advice on the best lighting conditions for the particular student together with use of contrasting tones to make things easier to see.
Career Guidance must be realistic but not too restrictive; labels like 'deafblind' to an employer mean 'unable to hear or see anything'. With Usher's this is rarely the case, particularly in the young adult. What needs to be answered is, 'can the employee, given the restricted hearing and vision he has, do the job?' The employer needs to know that certain aids such as CCTV can be loaned through the Placement Advisory C Teams to help the employee.
Certain jobs involving driving or use of dangerous machinery should be avoided, and again early diagnosis will help prevent these choices.
As vision deteriorates, help will be needed with mobility and daily living skills such as cooking. Braille can be introduced even if it is only used for labelling and the family helped with finger spelling. However, 'blind' skills should not be suggested until they are really necessary. For example, Braille should be introduced when the user understands the need for it and still has sufficient vision to enable learning to proceed more quickly.
Can counselling help?
This service will be an ongoing requirement possibly through the life of the individual as he attempts to adjust to decreasing vision. Centres where Usher syndrome is understood and where they can meet others similarly affected to talk out their difficulties, need to be planned. For an individual with Usher syndrome, the knowledge that he is not the only one with his condition, that he can meet someone in the same situation, that he is 'understood' and does not have to 'keep up a front', is invaluable. Supports such as these are provided through Sense (UK) and through the Retina International Youth group.
by Mary Guest, Head of Usher Services at Sense (UK)
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