Usher Syndrome

What It Is, Causes, Signs and Symptoms, Treatment, and More

Author: Emily Miao, PharmD

Editor: Alyssa Haag

Editor: Lily Guo

Editor: Kelsey LaFayette, DNP

Illustrator: Jessica Reynolds, MS

Modified: Jan 06, 2025

What is Usher syndrome?

Usher syndrome is a rare genetic condition that affects the cochlea and retina and is characterized by varying degrees of hearing and balance problems, as well as vision loss. The vision problems seen in Usher syndrome are due to a degenerative eye condition called retinitis pigmentosa (RP). RP is a group of rare, inherited eye disorders that affect the photoreceptor cells (e.g., rods and cones) of the retina, resulting in loss of color and peripheral side vision and eventually, central vision. Usher syndrome is the most common form of syndromic RP (i.e., RP with multiorgan involvement not limited to the eye) and people with Usher syndrome are also at higher risk of other eye diseases including keratoconus (i.e., an eye disease that affects the structure of the cornea resulting in vision loss). The estimated prevalence of Usher syndrome ranges from 2 to 6 cases per 100,000 individuals. Moreover, there are three major types of Usher syndrome: type 1, where individuals are born with profound hearing loss and experience balance problems from an early age, as well as vision problems that progress to complete blindness by adulthood; type 2, where individuals are born with moderate to severe hearing loss and vision problems which begin during early adolescence or adulthood; and type 3, where individuals develop hearing and vision loss in early adolescence or adulthood. Types 1 and 2 are the most common forms of Usher syndrome. Of note, life expectancy is not affected for those with Usher syndrome.

An infographic detailing the causes, signs and symptoms, diagnosis, and treatment of Usher Syndrome

What causes Usher syndrome?

Usher syndrome is caused by inherited genetic mutations of the sensory cells located in the retina and cochlea, which are responsible for vision, hearing, and balance. Several genetic mutations implicated in Usher syndrome have been identified including MYO7A, USH1C, USH2A, and CDH23. Usher syndrome follows an autosomal recessive inheritance pattern, meaning that two mutated copies of the gene are required to cause disease.

What are the signs and symptoms of Usher syndrome?

Signs and symptoms of Usher syndrome include varying degrees of hearing, vision, and balance impairments depending on the subtype involved. For example, hearing loss at birth may not be immediately obvious, therefore lack of startling, absence of babbling, or unresponsiveness to voices may be suggestive signs. Children with Usher syndrome may also experience delayed speech development and behavioral changes in adolescence as they struggle with hearing. Other signs include self-reported vision problems (e.g., blurred vision., sensitivity to light), clumsiness (e.g., bumping into objects), and balance issues (e.g., dizziness, vertigo, and/or frequent falls).

How is Usher syndrome diagnosed?

Diagnosis of Usher syndrome begins with a thorough review of symptoms and medical history. An ophthalmologic exam which can include visual acuity and field testing (i.e., to assess for sharpness of vision and peripheral vision, respectively) and/or optical coherence tomography (i.e., a non-invasive imaging test that provides cross-sectional images of the retina) can help diagnose RP, which is responsible for the vision problems in individuals with Usher syndrome. Additionally, an electroretinogram (ERG) may be performed to measure the electrical activity of the retina in response to light. During the ERG, a thin fiber electrode is placed in contact with the cornea; abnormal results can be diagnostic of RP.

An audiometry test can also be used to measure the individual’s ability to hear different pitches and volumes of sound. A focused neurologic exam can be performed to exclude central etiologies that could be related to balance and clumsiness, if present (e.g., stroke or brain neoplasm). The diagnosis of Usher syndrome is ultimately established through genetic testing and identification of a pathologic variant among one of the implicated genes (e.g., MYO7A, USH1, CDH23, etc.) through single gene testing, which identifies one specific gene, or through a screening gene panel, which can identify multiple genes simultaneously.

How is Usher syndrome treated?

There is currently no cure for Usher syndrome, therefore, treatment mainly consists of multidisciplinary care aimed at improving the individual’s quality of life. To treat hearing-related problems, hearing aids can be used to amplify transmitted sounds. A cochlear implant, which bypasses the damaged parts of the inner ear and directly stimulates the auditory nerve, may be another option for individuals with profound hearing loss. Speech therapy for hearing-impaired individuals can also be beneficial.

For vision-related problems, visual aids such as magnifying glasses can be helpful. Novel gene therapy with Voretigene neparvovec-rzyl which targets the RPE65 gene in RP and has shown promising results in clinical trials, may help vision-related impairments.

For balance-related problems, referral to an occupational and physical therapist can help create an individualized vestibular rehabilitation plan designed to improve balance and coordination. Finally, genetic counseling is often recommended for the individual and their family members to improve disease awareness and to discuss the risks of passing on the disease to future offspring.

What are the most important facts to know about Usher syndrome?

Usher syndrome is a rare, autosomal recessive genetic condition that affects the cochlea and retina and causes varying degrees of hearing, vision, and balance problems. Usher syndrome is caused by inherited genetic mutations (e.g., MYO7A, USH1, and CDH23, among others) of the sensory cells located in the retina and cochlea, which are responsible for vision, hearing, and balance. Signs and symptoms of Usher syndrome include varying degrees of hearing, vision, and balance impairments depending on the subtype involved. The diagnosis of Usher syndrome is ultimately established through genetic testing and identification of a pathologic genetic variant. Finally, there is currently no cure for Usher syndrome, therefore, treatment is largely aimed at improving the individual’s quality of life. Treatment options include hearing aids and/or cochlear implants for profound hearing loss; magnifying glasses and gene therapy for vision problems related to RP; and vestibular rehabilitation for balance-related issues.

References

Ahmed ZM, Riazuddin S, Aye S, et al. Gene structure and mutant alleles of PCDH15: nonsyndromic deafness DFNB23 and type 1 Usher syndrome. Hum Genet. 2008;124(3):215-223. doi:10.1007/s00439-008-0543-3

Aparisi MJ, Aller E, Fuster-García C, et al. Targeted next generation sequencing for molecular diagnosis of Usher syndrome. Orphanet J Rare Dis. 2014;9:168. Published 2014 Nov 18. doi:10.1186/s13023-014-0168-7

Astuto LM, Bork JM, Weston MD, et al. CDH23 mutation and phenotype heterogeneity: a profile of 107 diverse families with Usher syndrome and nonsyndromic deafness. Am J Hum Genet. 2002;71(2):262-275. doi:10.1086/341558

Wolfrum U, Nagel-Wolfrum K. Das Usher-Syndrom, eine Ziliopathie des Menschen [The Usher Syndrome, a Human Ciliopathy]. Klin Monbl Augenheilkd. 2018;235(3):273-280. doi:10.1055/a-0573-9431

Pennings RJ, Huygen PL, Orten DJ, et al. Evaluation of visual impairment in Usher syndrome 1b and Usher syndrome 2a. Acta Ophthalmol Scand. 2004;82(2):131-139. doi:10.1111/j.1600-0420.2004.00234.x