Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.
Eyes front and ears open. Class is now in session.
The rare disease that we will be learning about today is:
What is Usher Syndrome?
- Usher syndrome is the most common condition that affects both hearing and vision; sometimes it also affects balance. The major symptoms of Usher syndrome are deafness or hearing loss and an eye disease called retinitis pigmentosa (RP)
- Approximately 50,000 people in the U.S. have Usher syndrome, and the number continues to increase with age
- A loss of hearing occurs through injury of hair cells in the inner ear. Normally, these hair cells are put in motion through mechanical signals and thereby produce nerve activity. Damage to the hair cells does not allow, or only allows, insufficient transduction of the signal: Inner ear hearing loss and deafness is the result. The visual impairment is caused by a degeneration of the retina when individual photoreceptors (retinitis pigmentosa) are destroyed. It proceeds from the outer to the inner field of vision.
- Patients with Usher syndrome type 2 (USH2), the most common type of Usher Syndrome, have a moderate to severe hearing impairment from birth and commonly experience the first symptoms of night blindness in their second decade of life, which progresses to complete blindness by the third or fourth decade of life.
- The progressive vision loss in these patients is known as retinitis pigmentosa (RP).
- Early diagnosis of Usher syndrome is very important because the earlier a child receives the special assistance he or she needs, the better equipped the child is to manage his or her hearing and vision loss.
How Do You Get It?
- There are three different forms of Usher syndrome and each type is linked to mutations impacting different genes.
- Type I is linked to mutations affecting six genes (USH1B-G)
- Type II is linked to mutations affecting three genes (USH2A, USH2C, USH2D)
- Type III is linked to mutations affecting the USH3A gene
What Are The Symptoms?
- Usher syndrome is defined by a combination of hearing loss and vision loss
- Hearing impairment usually is apparent from birth; meanwhile, vision loss progressively worsens throughout the life of the patient
- By the teen years, many patients begin to experience night blindness (loss of night vision)
- By the twenties, the visual field begins to shrink, and many patients will be completely blind by the fifth or sixth decade
How Is It Treated?
- Although there is no cure for Usher syndrome, children with Usher syndrome can live full and happy lives with the help of education and training programs that meet their needs.
- Currently, there are only insufficient and experimental treatment options available for the degeneration of the retina. They all aim at delaying the complete destruction of the photoreceptors. In the case of complete deafness, as with type 1 Usher syndrome, a cochlear implant can be considered, especially with children. As an artificial inner ear replacement, it enables the direct transduction of the acoustic signal to the auditory nerve.
- By contrast, the reduced hearing ability with type 2 Usher syndrome can be effectively treated with binaural hearing aids, which amplify residual hearing. Hence, it is very important that an experienced hearing specialist select the appropriate hearing system and perform an optimal fitting. With the right hearing aids, patients suffering from Usher syndrome will be enabled to lead a more fulfilling life, rich in sounds.
- Common treatments for Usher syndrome include:
- Hearing aids.
- Assistive listening devices (various devices, including headsets, microphones, hearing aids, specifically adapted phones and others devices, which amplify the sounds of conversation between a listener and a talker).
- Cochlear implants.
- American Sign Language.
- Orientation and mobility training.
- Braille instruction.
- Low-vision services.
- Auditory (hearing) training.
- There are no FDA approved treatments at this time.
- Some ophthalmologists believe that a high dose of vitamin A palmitate may slow, but not halt, the progression of retinitis pigmentosa.
- Future avenues of treatment research include gene therapy.