Usher Syndrome, Type Iiia (USH3A)

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GARD: ¹⁹ Usher syndrome is a genetic disorder characterized by sensorineural hearing loss or deafness and progressive vision loss due to retinitis pigmentosa. Sensorineural hearing means it is caused by abnormalities of the inner ear. Retinitis pigmentosa is an eye disease that affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss occurs as the light-sensing cells of the retina gradually deteriorate. Night vision loss begins first, followed by blind spots that develop in the side (peripheral) vision, that can enlarge and merge to produce tunnel vision (loss of all peripheral vision). In some cases, vision is further impaired by clouding of the lens of the eye (cataracts). It is inherited in an autosomal recessive manner.

MalaCards based summary: Usher Syndrome, Type Iiia, also known as usher syndrome type 3, is related to usher syndrome, type ij and usher syndrome, type if. An important gene associated with Usher Syndrome, Type Iiia is CLRN1 (Clarin 1), and among its related pathways/superpathways are Olfactory Signaling Pathway and Sensory processing of sound. Affiliated tissues include eye, retina and brain, and related phenotypes are sensorineural hearing impairment and abnormal electroretinogram

UniProtKB/Swiss-Prot: ⁷³ USH is a genetically heterogeneous condition characterized by the association of retinitis pigmentosa with sensorineural deafness. Age at onset and differences in auditory and vestibular function distinguish Usher syndrome type 1 (USH1), Usher syndrome type 2 (USH2) and Usher syndrome type 3 (USH3). USH3 is characterized by postlingual, progressive hearing loss, variable vestibular dysfunction, and onset of retinitis pigmentosa symptoms, including nyctalopia, constriction of the visual fields, and loss of central visual acuity, usually by the second decade of life.

Orphanet: ⁵⁸ A rare ciliopathy characterized by progressive hearing and visual loss in the first decades of life and, in some cases, vestibular dysfunction. Patients have normal hearing at birth. Onset of hearing loss is usually in late childhood or adolescence after development of speech. Profound deafness is mostly reported by middle age. Retinitis pigmentosa related visual loss also develops in late childhood or adolescence. Developmental motor milestones are generally normal but vestibular dysfunction may occur in adulthood.

OMIM®: ⁵⁷ Usher syndrome type III is characterized by postlingual, progressive hearing loss, variable vestibular dysfunction, and onset of retinitis pigmentosa symptoms, including nyctalopia, constriction of the visual fields, and loss of central visual acuity, usually by the second decade of life (Karjalainen et al., 1985; Pakarinen et al., 1995). For a discussion of phenotypic heterogeneity of Usher syndrome, see USH1 (276900). (276902) (Updated 08-Dec-2022)

Disease Ontology ¹¹ Usher syndrome type 3: An Usher syndrome characterized by progressive hearing loss typically beginning in late childhood, variable vestibular dysfunction and onset of retinitis pigmentosa by the second decade of life.

Usher syndrome type 3a: An Usher syndrome type 3 that has material basis in homozygous or compound heterozygous mutation in the CLRN1 gene on chromosome 3q25.

Wikipedia: ⁷⁵ Usher syndrome, also known as Hallgren syndrome, Usher-Hallgren syndrome, retinitis pigmentosa-dysacusis... more...

Clinical features from OMIM®:

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