13, 14 The standard approach is to offer bilateral cochlear implants to Usher 1 patients within the first 2 years of life.įlowchart for investigation and treatment of bilateral profound sensorineural hearing loss. An earlier age of implantation is correlated with improved outcome. Timely use of cochlear implants can achieve oral communication and open set speech perception. Due to the profound nature of deafness, children with Usher 1 derive limited or no benefit from hearing aids and most patients with Usher 1 would be sign language users if the hearing loss is not treated effectively.

When older, they compensate for their vestibular areflexia using vision, until the onset of RP, although they often have higher accidental falls and difficulty in performing activities, which require balance, for example, riding a bicycle. Vestibular areflexia is reflected in delayed motor development and children usually do not walk independently before the age of 18 months. 11 Infants are detected through the newborn hearing screen ( Figure 2), and where not undertaken/available, the diagnosis is often suspected in infancy. It accounts for approximately 25–44% of all Usher syndrome cases. Usher syndrome type 1 (Usher 1) is the most severe subtype in which patients exhibit severe to profound bilateral congenital sensorineural hearing loss ( Figure 1), most frequently non-progressive, with vestibular areflexia. Source: Data included from previous studies. While many promising treatments are under investigation, there is no approved treatment for this disease to date. The Usher genes encode a variety of proteins that are expressed in the inner ear and retina where they perform essential functions in sensory hair cell development and function, and photoreceptor maintenance. 2, 4 Usher syndrome is both clinically and genetically heterogeneous and is divided into three distinct clinical subtypes, associated with a number of genetic loci. 2, 3 Furthermore, it has been estimated to represent 5% of all congenital deafness and 18% of all retinitis pigmentosa (RP) cases. 1, 2 It has an estimated prevalence of between 4 and 17 in 100 000 people worldwide. It is the most common cause of combined sight and hearing loss, accounting for more than half of deaf–blindness cases. Usher syndrome encompasses a group of inherited disorders characterised by dual sensory impairment of the auditory and visual systems, with a variable presentation of vestibular dysfunction in a proportion of cases. While there is currently no available approved treatment for the RP, various therapeutic strategies are in development or in clinical trials for Usher syndrome, including gene replacement, gene editing, antisense oligonucleotides and small molecule drugs. Hearing loss is managed with hearing aids and cochlear implants, which has made a significant improvement in quality of life for patients. Genotype–phenotype correlations have been described for several of the Usher genes. Variants in these genes can also cause non-syndromic RP and deafness. To date, 10 causative genes have been identified for Usher syndrome, with MYO7A accounting for >50% of type 1 and USH2A contributing to approximately 80% of type 2 Usher syndrome. It is the most common cause of deaf–blindness worldwide with a prevalence of between 4 and 17 in 100 000. Usher syndrome has three subtypes, each being clinically and genetically heterogeneous characterised by sensorineural hearing loss and retinitis pigmentosa (RP), with or without vestibular dysfunction.

Type 2a usher syndrome