Hearing Loss and Pigmentary Retinopathy: Usher Syndrome
Usher syndrome is the most common name used to describe the association of retinitis pigmentosa (RP) with congenital sensorineural hearing loss, whether partial or profound. The prevalence of Usher syndrome is thought to be 3 cases per 100,000 persons. There are 3 types of Usher syndrome; patients with type 1 have early and profound deafness, RP, and vestibular areflexia. Type 2 patients are born with moderate to severe hearing loss and develop RP within their second decade but have normal vestibular function. Type 3 patients have progressive hearing loss, variable RP, and sporadic vestibular function.
All forms show autosomal recessive inheritance. Currently, 16 genetic loci have been identified as associated with Usher syndrome. The proteins encoded by these genes are part of a dynamic protein complex present in the cilia of the inner ear and in the cone outer segments of the photoreceptor cells of the retina. Other genetic conditions and environmental factors that may also lead to pigmentary retinopathy and hearing loss include Alport, Alström, Cockayne, and Hurler syndromes; spondyloepiphyseal dysplasia congenita; Refsum disease; and congenital rubella.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.