From the Guidelines
Usher syndrome is a rare genetic disorder characterized by hearing loss and progressive vision loss due to retinitis pigmentosa, with management focusing on addressing both sensory impairments through hearing aids, cochlear implants, low vision services, and genetic counseling. It is the most common condition affecting both hearing and vision, occurring in approximately 3-10 per 100,000 people 1. There are three clinical types of Usher syndrome, with Type 1 being the most severe (profound congenital deafness and early-onset retinitis pigmentosa), Type 2 featuring moderate to severe hearing loss and later-onset vision problems, and Type 3 showing progressive hearing and vision loss.
Key Characteristics
- Usher syndrome is associated with significant morbidity and mortality, primarily due to the progressive nature of the vision and hearing loss, which can lead to complete blindness and deafness if left untreated or poorly managed 1.
- The condition is inherited in an autosomal recessive pattern, emphasizing the importance of genetic counseling for affected individuals and their families 1.
- Early intervention is crucial, with children often benefiting from sign language instruction, specialized educational programs, and assistive technologies to improve their quality of life and adapt to the progressive nature of the condition.
Management and Treatment
- Management of Usher syndrome involves a multidisciplinary approach, including audiologists, ophthalmologists, genetic counselors, and other specialists to address both the hearing and vision impairments 1.
- Regular monitoring is essential to manage symptoms and adapt interventions as the condition progresses, including the use of hearing aids, cochlear implants, and low vision services.
- Currently, there is no cure for Usher syndrome, but research is ongoing, including gene therapy approaches, which may offer future treatment options for improving morbidity, mortality, and quality of life outcomes.
From the Research
Definition and Characteristics of Usher Syndrome
- Usher syndrome (US) is a clinically and genetically heterogeneous disorder characterized by sensorineural hearing loss, retinitis pigmentosa (RP), and vestibular impairment 2, 3.
- It is the most common cause of deaf-blindness worldwide, with a prevalence of 4-17/100,000 2.
- The disorder is autosomal recessive, meaning that it is permanently and severely affects the senses of hearing, vision, and balance 3.
Clinical Types of Usher Syndrome
- There are three clinically distinct types of Usher syndrome, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction 3, 4.
- Usher syndrome type 2 (USH2) is the most prevalent, with mutations in USH2A, ADGRV1, and WHRN being responsible for the condition 4.
Genetic Basis of Usher Syndrome
- Nine confirmed and two suspected USH-causative genes have been identified, with MYO7A and USH2A being major players in US types 1 and 2, respectively 2, 3.
- Genetic research has provided crucial insights into the complexity of US, with variants in these genes contributing to isolated forms of hearing loss and RP 2.
- Molecular testing can further distinguish USH subtypes by causative gene, and is important for coordinating care among an interdisciplinary team 5.
Diagnosis and Treatment of Usher Syndrome
- A clinical diagnosis of Usher syndrome is made by the presence of retinitis pigmentosa (RP) with sensorineural hearing loss (SNHL) 5.
- Molecular testing and diagnosis should be part of the routine care of USH individuals to facilitate earlier interventions and coordinated care between ophthalmology and audiology 5.
- While there is no cure for Usher syndrome, genetic therapies are rapidly developing, and may benefit from detailed genetic information to identify effective strategies for restoring functional USH proteins 3, 4.