Usher syndrome is the most common inherited cause of combined deaf-blindness, an autosomal recessive disorder characterized by sensorineural hearing loss, progressive retinitis pigmentosa, and, in some forms, vestibular dysfunction. The disease results from mutations in genes encoding components of the Usher protein interactome, a network of proteins that organize the cohesion of the stereocilia hair bundle in cochlear and vestibular hair cells and that participate in trafficking at the photoreceptor periciliary/connecting-cilium region. Three classical clinical types are recognized: USH1 (severe-to-profound congenital deafness, absent vestibular function, adolescent-onset retinitis pigmentosa), USH2 (moderate-to-severe congenital hearing loss, generally normal vestibular function, later-onset retinitis pigmentosa), and USH3 (progressive postlingual hearing loss, variable vestibular involvement, variable retinitis pigmentosa onset).
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name: Usher Syndrome
creation_date: "2026-06-22T00:00:00Z"
category: Mendelian
synonyms:
- Usher syndrome
- Retinitis pigmentosa-deafness syndrome
- Hallgren syndrome
- Deaf-blindness, Usher type
description: >
Usher syndrome is the most common inherited cause of combined deaf-blindness,
an autosomal recessive disorder characterized by sensorineural hearing loss,
progressive retinitis pigmentosa, and, in some forms, vestibular dysfunction.
The disease results from mutations in genes encoding components of the Usher
protein interactome, a network of proteins that organize the cohesion of the
stereocilia hair bundle in cochlear and vestibular hair cells and that
participate in trafficking at the photoreceptor periciliary/connecting-cilium
region. Three classical clinical types are recognized: USH1 (severe-to-profound
congenital deafness, absent vestibular function, adolescent-onset retinitis
pigmentosa), USH2 (moderate-to-severe congenital hearing loss, generally normal
vestibular function, later-onset retinitis pigmentosa), and USH3 (progressive
postlingual hearing loss, variable vestibular involvement, variable retinitis
pigmentosa onset).
disease_term:
preferred_term: Usher syndrome
term:
id: MONDO:0019501
label: Usher syndrome
parents:
- Inherited retinal dystrophy
- Sensorineural hearing loss
- Ciliopathy
references:
- reference: PMID:20301442
title: "Usher Syndrome Type I."
tags:
- GeneReviews
- reference: PMID:20301515
title: "Usher Syndrome Type II."
tags:
- GeneReviews
- reference: PMID:11524702
title: Mutations in a novel gene with transmembrane domains underlie Usher syndrome type 3.
- reference: PMID:16987892
title: "Usher syndrome: molecular links of pathogenesis, proteins and pathways."
- reference: PMID:20440071
title: PDZD7 is a modifier of retinal disease and a contributor to digenic Usher syndrome.
- reference: PMID:35353227
title: "The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification."
- reference: PMID:24239741
title: Usher protein functions in hair cells and photoreceptors.
- reference: PMID:32995707
title: "Usher syndrome: clinical features, molecular genetics and advancing therapeutics."
- reference: PMID:33193648
title: "Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy."
- reference: PMID:33895329
title: Antisense oligonucleotide-based treatment of retinitis pigmentosa caused by USH2A exon 13 mutations.
- reference: clinicaltrials:NCT06591793
title: A Phase 1/2 Multicenter, Open-label, Dose Escalation, Safety and Efficacy Study of Subretinal Administration of Dual AAV8.MYO7A, AAVB-081 in Subjects With Usher Syndrome Type IB (USH1B) Retinitis Pigmentosa
- reference: clinicaltrials:NCT06627179
title: A Two-Year Double-masked, Randomized, Sham-Controlled Study to Evaluate the Efficacy, Safety and Tolerability of Ultevursen in Subjects With Retinitis Pigmentosa (RP) Due to Mutations in Exon 13 of the USH2A Gene
inheritance:
- name: Autosomal Recessive
inheritance_term:
preferred_term: Autosomal recessive inheritance
term:
id: HP:0000007
label: Autosomal recessive inheritance
evidence:
- reference: PMID:33193648
reference_title: "Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance."
explanation: Confirms the autosomal recessive inheritance pattern of Usher syndrome.
- name: Digenic inheritance
inheritance_term:
preferred_term: Digenic inheritance
term:
id: HP:0010984
label: Digenic inheritance
description: >-
In addition to the classic autosomal recessive monogenic forms, a subset of
Usher syndrome shows digenic inheritance, in which a heterozygous PDZD7
variant contributes together with variants in a second Usher gene (e.g.,
ADGRV1/GPR98 or USH2A); PDZD7 also acts as a retinal disease modifier.
evidence:
- reference: PMID:20440071
reference_title: "PDZD7 is a modifier of retinal disease and a contributor to digenic Usher syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Further, heterozygous PDZD7 mutations were present in patients with
truncating mutations in USH2A, G protein-coupled receptor 98 (GPR98; also
known as USH2C), and an unidentified locus.
explanation: >-
A heterozygous truncating PDZD7 variant was found in Usher patients who
also carried mutations in a second Usher gene, supporting a digenic
contribution of PDZD7.
- reference: PMID:20440071
reference_title: "PDZD7 is a modifier of retinal disease and a contributor to digenic Usher syndrome."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: >-
We validated the human genotypes using zebrafish, and our findings were consistent
with digenic inheritance of PDZD7 and GPR98, and with PDZD7 as a retinal disease
modifier in patients with USH2A.
explanation: >-
The primary study's zebrafish validation supports both PDZD7-GPR98 digenic
inheritance and PDZD7 modification of USH2A-associated retinal disease.
prevalence:
- population: General population (worldwide)
measure_type: POINT_PREVALENCE
rate_low: 4.0
rate_high: 17.0
percentage: 4-17 per 100,000
notes: >-
Usher syndrome is the most common cause of deaf-blindness worldwide. The
reported range straddles two schema prevalence bands, so no single
prevalence_class is asserted; the numeric bounds retain the source precision.
evidence:
- reference: PMID:32995707
reference_title: "Usher syndrome: clinical features, molecular genetics and advancing therapeutics."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "It is the most common cause of deaf-blindness worldwide with a prevalence of between 4 and 17 in 100 000."
explanation: Documents the worldwide prevalence and deaf-blindness burden of Usher syndrome.
has_subtypes:
- name: USH1
display_name: Usher syndrome type 1
subtype_term:
preferred_term: Usher syndrome type 1
term:
id: MONDO:0010168
label: Usher syndrome type 1
description: >
Congenital profound bilateral sensorineural hearing loss,
absent vestibular responses, and
adolescent-onset retinitis pigmentosa. Caused by biallelic mutations in
MYO7A (USH1B), USH1C (harmonin), CDH23 (USH1D), PCDH15 (USH1F), or USH1G
(SANS/sans).
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type I (USH1) is characterized by congenital bilateral profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa (RP)."
explanation: Supports the defining auditory, vestibular, and retinal presentation of USH1.
- name: USH2
display_name: Usher syndrome type 2
subtype_term:
preferred_term: Usher syndrome type 2
term:
id: MONDO:0016484
label: Usher syndrome type 2
description: >
Moderate-to-severe congenital hearing loss that is sloping
(worse at high frequencies), intact or variable vestibular responses, and
progressive retinitis pigmentosa. Caused by biallelic
mutations in USH2A (usherin), ADGRV1 (USH2C, GPR98/VLGR1), or WHRN (USH2D,
whirlin).
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type II (USH2) is characterized by the following: Congenital, bilateral sensorineural hearing loss that is mild to moderate in the low frequencies and severe to profound in the higher frequencies. Intact or variable vestibular responses."
explanation: Supports the characteristic hearing-loss profile and vestibular findings of USH2.
- name: USH3
display_name: Usher syndrome type 3
subtype_term:
preferred_term: Usher syndrome type 3
term:
id: MONDO:0016485
label: Usher syndrome type 3
description: >
Progressive postlingual sensorineural hearing loss, variable vestibular
dysfunction, and variable-onset retinitis pigmentosa. Caused by biallelic
mutations in CLRN1 (clarin-1).
evidence:
- reference: PMID:11524702
reference_title: "Mutations in a novel gene with transmembrane domains underlie Usher syndrome type 3."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type 3 (USH3) is an autosomal recessive disorder characterized by progressive hearing loss, severe retinal degeneration, and variably present vestibular dysfunction, assigned to 3q21-q25."
explanation: Supports the progressive auditory, retinal, and variably vestibular USH3 presentation.
pathophysiology:
- name: Usher Protein Complex Loss of Function
description: >-
Biallelic pathogenic variants disrupt the relevant Usher protein and its
tissue-specific protein complex. Across the classical subtypes, these
complexes support structures in both sensory-hair bundles and photoreceptor
calycal/periciliary regions; the two tissue effects are parallel branches,
not a causal sequence from ear to retina.
biological_scale: MOLECULAR
downstream:
- target: Usher Interactome Disruption in the Hair Bundle
description: Loss of the relevant Usher-complex component disrupts hair-bundle organization.
causal_link_type: DIRECT
evidence:
- reference: PMID:16987892
reference_title: "Usher syndrome: molecular links of pathogenesis, proteins and pathways."
supports: SUPPORT
evidence_source: OTHER
snippet: "The localization of the Usher proteins and the phenotype in animal models indicate that the Usher protein complex is essential in the morphogenesis of the stereocilia bundle in hair cells and in the calycal processes of photoreceptor cells."
explanation: Supports the hair-cell branch from loss of Usher-complex function.
- target: Photoreceptor Connecting Cilium Dysfunction
description: Loss of the relevant Usher-complex component disrupts photoreceptor calycal/periciliary organization.
causal_link_type: DIRECT
evidence:
- reference: PMID:16987892
reference_title: "Usher syndrome: molecular links of pathogenesis, proteins and pathways."
supports: SUPPORT
evidence_source: OTHER
snippet: "The localization of the Usher proteins and the phenotype in animal models indicate that the Usher protein complex is essential in the morphogenesis of the stereocilia bundle in hair cells and in the calycal processes of photoreceptor cells."
explanation: Supports the parallel photoreceptor branch from loss of Usher-complex function.
evidence:
- reference: PMID:16987892
reference_title: "Usher syndrome: molecular links of pathogenesis, proteins and pathways."
supports: SUPPORT
evidence_source: OTHER
snippet: "The localization of the Usher proteins and the phenotype in animal models indicate that the Usher protein complex is essential in the morphogenesis of the stereocilia bundle in hair cells and in the calycal processes of photoreceptor cells."
explanation: Supports a shared upstream Usher-complex defect with parallel auditory and retinal consequences.
- name: Usher Interactome Disruption in the Hair Bundle
description: >
The Usher proteins (myosin VIIa, harmonin, cadherin-23, protocadherin-15,
sans, usherin, ADGRV1/VLGR1, whirlin, clarin-1) form an interconnected
network that builds and maintains the cohesion of the stereocilia hair bundle
in cochlear and vestibular hair cells. Cadherin-23 and protocadherin-15
constitute the tip-link that gates the mechanotransduction channel, while
harmonin, sans, and myosin VIIa anchor the link complex and stabilize bundle
architecture during development. Loss of Usher-complex function can disrupt
hair-bundle morphogenesis or tip-link organization and mechanotransduction.
biological_scale: TISSUE
cell_types:
- preferred_term: cochlear inner hair cell
term:
id: CL:0000589
label: cochlear inner hair cell
- preferred_term: cochlear outer hair cell
term:
id: CL:0000601
label: cochlear outer hair cell
locations:
- preferred_term: spiral organ of Corti
term:
id: UBERON:0002227
label: spiral organ of cochlea
biological_processes:
- preferred_term: mechanoreceptor differentiation
term:
id: GO:0042490
label: mechanoreceptor differentiation
modifier: ABNORMAL
downstream:
- target: Hair Cell Mechanotransduction Failure
description: >
Disorganized hair bundles and disrupted tip-links abolish the
mechanotransduction current.
causal_link_type: DIRECT
evidence:
- reference: PMID:24239741
reference_title: "Usher protein functions in hair cells and photoreceptors."
supports: SUPPORT
evidence_source: OTHER
snippet: "In mature hair cells, homodimers of the Usher cadherins, cadherin 23 and protocadherin 15, interact to form a structural fiber, the tip link, and the linkages that anchor the taller stereocilia's actin cytoskeleton core to the shorter adjacent stereocilia and the elusive mechanotransduction channels, explaining the deafness phenotype when these molecular interactions are perturbed."
explanation: Supports the direct link between disruption of the Usher tip-link complex and mechanotransduction failure.
evidence:
- reference: PMID:24239741
reference_title: "Usher protein functions in hair cells and photoreceptors."
supports: SUPPORT
evidence_source: OTHER
snippet: "In mature hair cells, homodimers of the Usher cadherins, cadherin 23 and protocadherin 15, interact to form a structural fiber, the tip link, and the linkages that anchor the taller stereocilia's actin cytoskeleton core to the shorter adjacent stereocilia and the elusive mechanotransduction channels, explaining the deafness phenotype when these molecular interactions are perturbed."
explanation: Establishes that cadherin-23/protocadherin-15 form the tip-link and that disruption explains the deafness phenotype.
- reference: PMID:16987892
reference_title: "Usher syndrome: molecular links of pathogenesis, proteins and pathways."
supports: SUPPORT
evidence_source: OTHER
snippet: "The localization of the Usher proteins and the phenotype in animal models indicate that the Usher protein complex is essential in the morphogenesis of the stereocilia bundle in hair cells and in the calycal processes of photoreceptor cells."
explanation: Supports the role of the Usher protein complex in stereocilia bundle morphogenesis.
- name: Hair Cell Mechanotransduction Failure
description: >
Disruption of the tip-link and hair-bundle architecture prevents
deflection-gated opening of the mechanotransduction channel, so hair cells
cannot convert sound-evoked or head-movement-evoked bundle deflection into a
receptor potential. The result is sensorineural hearing loss and, in USH1,
vestibular areflexia.
biological_scale: CELLULAR
cell_types:
- preferred_term: cochlea auditory hair cell
term:
id: CL:4023120
label: cochlea auditory hair cell
biological_processes:
- preferred_term: sensory perception of sound
term:
id: GO:0007605
label: sensory perception of sound
modifier: DECREASED
downstream:
- target: Sensorineural Hearing Loss
description: Loss of cochlear hair cell transduction causes sensorineural hearing loss.
causal_link_type: DIRECT
evidence:
- reference: PMID:33193648
reference_title: "Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy."
supports: SUPPORT
evidence_source: OTHER
snippet: "Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction."
explanation: Review synthesis supports the route from Usher-complex disruption through mechanotransduction failure to hearing loss.
- target: Congenital Sensorineural Hearing Loss
description: >
When the Usher protein is required for hair-bundle development, transduction
failure is present from birth, producing congenital sensorineural hearing
loss (USH1/USH2).
causal_link_type: DIRECT
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type I (USH1) is characterized by congenital bilateral profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa (RP)."
explanation: Establishes congenital profound sensorineural hearing loss in USH1.
- target: Vestibular Dysfunction
description: >
Loss of vestibular hair cell transduction causes vestibular areflexia,
most pronounced in USH1.
causal_link_type: DIRECT
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type I (USH1) is characterized by congenital bilateral profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa (RP)."
explanation: Establishes vestibular areflexia in USH1.
- target: Delayed Motor Development
description: Vestibular areflexia delays motor development and independent walking in USH1.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- absent vestibular input
- impaired postural and balance control in infancy
evidence:
- reference: PMID:35353227
reference_title: "The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification."
supports: SUPPORT
evidence_source: OTHER
snippet: "Many USH1 patients do not begin to walk before the age of 18 months, and vestibular areflexia is responsible for the delayed motor development observed in these patients"
explanation: Review synthesis explicitly supports vestibular areflexia as the cause of delayed walking and motor development in USH1.
evidence:
- reference: PMID:33193648
reference_title: "Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy."
supports: SUPPORT
evidence_source: OTHER
snippet: "Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction."
explanation: Directly links Usher gene mutations to inhibited mechanosensory transduction via tip-link destabilization.
- name: Photoreceptor Connecting Cilium Dysfunction
description: >
Usher proteins are also expressed at the photoreceptor periciliary and
connecting-cilium region, where they participate in protein trafficking
between the inner and outer segments. Model evidence suggests that disruption
can impair light-dependent protein translocation and intersegmental
trafficking; the precise contribution and strength of this mechanism vary
by Usher protein.
biological_scale: CELLULAR
cell_types:
- preferred_term: retinal rod cell
term:
id: CL:0000604
label: retinal rod cell
- preferred_term: photoreceptor cell
term:
id: CL:0000210
label: photoreceptor cell
locations:
- preferred_term: retina
term:
id: UBERON:0000966
label: retina
biological_processes:
- preferred_term: protein localization to cilium
term:
id: GO:0061512
label: protein localization to cilium
modifier: ABNORMAL
downstream:
- target: Photoreceptor Degeneration
description: >
Impaired ciliary transport and outer-segment maintenance cause progressive
photoreceptor loss.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
intermediate_mechanisms:
- impaired intraciliary protein transport
- outer-segment homeostatic failure
evidence:
- reference: PMID:24239741
reference_title: "Usher protein functions in hair cells and photoreceptors."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "Recent evidence linking photoreceptor cell dysfunction in the shaker 1 mouse model for Usher syndrome to light-induced protein translocation defects, combined with localization of an Usher protein interactome at the periciliary region of the photoreceptors suggests Usher proteins might regulate protein trafficking between the inner and outer segments of photoreceptors."
explanation: Supports a provisional model linking altered protein translocation to photoreceptor dysfunction without asserting a universal mechanism.
evidence:
- reference: PMID:24239741
reference_title: "Usher protein functions in hair cells and photoreceptors."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "Recent evidence linking photoreceptor cell dysfunction in the shaker 1 mouse model for Usher syndrome to light-induced protein translocation defects, combined with localization of an Usher protein interactome at the periciliary region of the photoreceptors suggests Usher proteins might regulate protein trafficking between the inner and outer segments of photoreceptors."
explanation: Supports an Usher-interactome role in periciliary protein trafficking between photoreceptor inner and outer segments.
- name: Photoreceptor Degeneration
description: >
Progressive rod-then-cone photoreceptor degeneration produces the clinical
picture of retinitis pigmentosa: nyctalopia and peripheral visual field
constriction first, followed by central acuity loss.
biological_scale: TISSUE
cell_types:
- preferred_term: photoreceptor cell
term:
id: CL:0000210
label: photoreceptor cell
biological_processes:
- preferred_term: visual perception
term:
id: GO:0007601
label: visual perception
modifier: DECREASED
downstream:
- target: Retinitis Pigmentosa
description: Progressive photoreceptor loss manifests clinically as retinitis pigmentosa.
causal_link_type: DIRECT
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "RP, a progressive bilateral symmetric degeneration of photoreceptors in the retina, develops in early adolescence, resulting in progressively constricted visual fields first, due to rod photoreceptor cell loss, followed by impaired visual acuity due to cone photoreceptor cell loss."
explanation: Defines Usher-associated retinitis pigmentosa as progressive photoreceptor degeneration.
- target: Night Blindness
description: Early rod loss produces nyctalopia.
causal_link_type: DIRECT
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Retinitis pigmentosa (RP); progressive, bilateral, symmetric retinal degeneration that begins with night blindness and constricted visual fields (tunnel vision) and eventually includes decreased central visual acuity"
explanation: Directly links progressive retinal degeneration with night blindness.
- target: Constricted Visual Fields
description: Progressive peripheral photoreceptor loss constricts the visual field.
causal_link_type: DIRECT
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "RP, a progressive bilateral symmetric degeneration of photoreceptors in the retina, develops in early adolescence, resulting in progressively constricted visual fields first, due to rod photoreceptor cell loss, followed by impaired visual acuity due to cone photoreceptor cell loss."
explanation: Directly links rod photoreceptor loss with progressive visual-field constriction.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "RP, a progressive bilateral symmetric degeneration of photoreceptors in the retina, develops in early adolescence, resulting in progressively constricted visual fields first, due to rod photoreceptor cell loss, followed by impaired visual acuity due to cone photoreceptor cell loss."
explanation: Establishes the rod-then-cone progression of photoreceptor degeneration producing field loss then acuity loss.
phenotypes:
- category: Auditory
name: Sensorineural Hearing Loss
description: >
Sensorineural hearing loss is a defining feature across the three classical
Usher subtypes, with subtype-dependent severity and course.
phenotype_term:
preferred_term: Sensorineural hearing impairment
term:
id: HP:0000407
label: Sensorineural hearing impairment
evidence:
- reference: PMID:32995707
reference_title: "Usher syndrome: clinical features, molecular genetics and advancing therapeutics."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "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."
explanation: Establishes sensorineural hearing loss as a defining feature of all Usher subtypes.
- category: Auditory
name: Congenital Sensorineural Hearing Loss
description: >
Congenital bilateral profound sensorineural hearing loss is characteristic
of USH1.
subtype: USH1
phenotype_term:
preferred_term: Congenital sensorineural hearing impairment
term:
id: HP:0008527
label: Congenital sensorineural hearing impairment
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type I (USH1) is characterized by congenital bilateral profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa (RP)."
explanation: Confirms congenital bilateral profound sensorineural hearing loss in USH1.
- category: Ophthalmologic
name: Retinitis Pigmentosa
description: >
Progressive retinitis pigmentosa is a defining retinal feature across the
three classical Usher subtypes, with variable onset and course.
phenotype_term:
preferred_term: Rod-cone dystrophy
term:
id: HP:0000510
label: Rod-cone dystrophy
clinical_course: PROGRESSIVE
evidence:
- reference: PMID:32995707
reference_title: "Usher syndrome: clinical features, molecular genetics and advancing therapeutics."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "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."
explanation: Establishes retinitis pigmentosa as a defining feature of Usher syndrome.
- category: Ophthalmologic
name: Cataract
description: >
Cataract is a potentially treatable ophthalmologic complication monitored
during USH2 surveillance.
phenotype_term:
preferred_term: Cataract
term:
id: HP:0000518
label: Cataract
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "detect potentially treatable complications such as cataracts, refractive errors, \nand cystoid macular edema."
explanation: >-
GeneReviews lists cataract among the treatable ophthalmologic complications
detected on surveillance in Usher syndrome type II.
- category: Ophthalmologic
name: Night Blindness
description: >
Nyctalopia (impaired vision in dim light) is an early symptom of the
rod-predominant photoreceptor degeneration.
phenotype_term:
preferred_term: Nyctalopia
term:
id: HP:0000662
label: Nyctalopia
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Retinitis pigmentosa (RP); progressive, bilateral, symmetric retinal degeneration that begins with night blindness and constricted visual fields (tunnel vision) and eventually includes decreased central visual acuity"
explanation: Documents night blindness as an early feature of the retinal degeneration in Usher syndrome.
- category: Ophthalmologic
name: Constricted Visual Fields
description: >
Progressive constriction of the peripheral visual field ("tunnel vision")
results from peripheral photoreceptor loss.
phenotype_term:
preferred_term: Constriction of peripheral visual field
term:
id: HP:0001133
label: Constriction of peripheral visual field
clinical_course: PROGRESSIVE
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "progressive, bilateral, symmetric retinal degeneration that begins with night blindness and constricted visual fields (tunnel vision)"
explanation: Documents progressive constriction of the visual field (tunnel vision) in Usher syndrome.
- category: Ophthalmologic
name: Abnormal Electroretinogram
description: >-
Electroretinography is part of the retinal functional evaluation in Usher
syndrome. Experimental Usher-protein defects produce decreased ERG responses;
the cited GeneReviews abstract does not specify a universal human waveform.
phenotype_term:
preferred_term: Abnormal electroretinogram
term:
id: HP:0000512
label: Abnormal electroretinogram
reports_on:
- target: Photoreceptor Degeneration
relationship: READOUT_OF
endpoint_context: DIAGNOSTIC
interpretation: Decreased electroretinographic responses report retinal photoreceptor dysfunction.
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The diagnosis of USH2 is established in a proband using electrophysiologic and subjective tests of hearing and retinal function."
explanation: Supports retinal electrophysiology as part of human diagnostic evaluation, without specifying the waveform.
- reference: PMID:35353227
reference_title: "The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "As in the inner ear, USH protein defects cause diverse phenotypic abnormalities in the retina, including decreased electroretinogram responses (ERGs), probably due to misshapen photoreceptor disks"
explanation: Model evidence supports decreased ERG responses as a readout of Usher-related retinal structural dysfunction.
- category: Vestibular
name: Vestibular Dysfunction
description: >
Absent vestibular responses (vestibular areflexia) are characteristic of
USH1.
subtype: USH1
phenotype_term:
preferred_term: Vestibular areflexia
term:
id: HP:0008568
label: Vestibular areflexia
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type I (USH1) is characterized by congenital bilateral profound sensorineural hearing loss, vestibular areflexia, and adolescent-onset retinitis pigmentosa (RP)."
explanation: Confirms vestibular areflexia as a defining feature of USH1.
- category: Neurologic
name: Delayed Motor Development
description: >-
Many children with USH1 do not walk before 18 months because vestibular
areflexia delays motor development.
subtype: USH1
phenotype_term:
preferred_term: Delayed gross motor development
term:
id: HP:0002194
label: Delayed gross motor development
evidence:
- reference: PMID:35353227
reference_title: "The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification."
supports: SUPPORT
evidence_source: OTHER
snippet: "Many USH1 patients do not begin to walk before the age of 18 months, and vestibular areflexia is responsible for the delayed motor development observed in these patients"
explanation: Supports delayed walking and motor development as a vestibular consequence in USH1.
genetic:
- name: MYO7A Mutations
association: Causative
subtype: USH1
gene_term:
preferred_term: MYO7A
term:
id: hgnc:7606
label: MYO7A
features: >
Biallelic mutations in MYO7A (myosin VIIa) cause Usher syndrome type 1B, the
most common USH1 subtype, accounting for more than 50% of USH1.
evidence:
- reference: PMID:32995707
reference_title: "Usher syndrome: clinical features, molecular genetics and advancing therapeutics."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "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."
explanation: Documents MYO7A as the major USH1 gene, accounting for more than 50% of type 1.
- name: USH1C Mutations
association: Causative
subtype: USH1
gene_term:
preferred_term: USH1C
term:
id: hgnc:12597
label: USH1C
features: >
Biallelic pathogenic variants in USH1C cause Usher syndrome type 1C.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of five genes – MYO7A, USH1C, CDH23, PCDH15, and USH1G – confirms the diagnosis."
explanation: Confirms USH1C as one of the five established USH1 genes.
- name: CDH23 Mutations
association: Causative
subtype: USH1
gene_term:
preferred_term: CDH23
term:
id: hgnc:13733
label: CDH23
features: >
Biallelic pathogenic variants in CDH23 cause Usher syndrome type 1D.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of five genes – MYO7A, USH1C, CDH23, PCDH15, and USH1G – confirms the diagnosis."
explanation: Confirms CDH23 as one of the five established USH1 genes.
- name: PCDH15 Mutations
association: Causative
subtype: USH1
gene_term:
preferred_term: PCDH15
term:
id: hgnc:14674
label: PCDH15
features: >
Biallelic pathogenic variants in PCDH15 cause Usher syndrome type 1F.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of five genes – MYO7A, USH1C, CDH23, PCDH15, and USH1G – confirms the diagnosis."
explanation: Confirms PCDH15 as one of the five established USH1 genes.
- name: USH1G Mutations
association: Causative
subtype: USH1
gene_term:
preferred_term: USH1G
term:
id: hgnc:16356
label: USH1G
features: >
Biallelic pathogenic variants in USH1G cause Usher syndrome type 1G.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of five genes – MYO7A, USH1C, CDH23, PCDH15, and USH1G – confirms the diagnosis."
explanation: Confirms USH1G as one of the five established USH1 genes.
- name: USH2A Mutations
association: Causative
subtype: USH2
gene_term:
preferred_term: USH2A
term:
id: hgnc:12601
label: USH2A
features: >
Biallelic mutations in USH2A (usherin) are the most common cause of Usher
syndrome type 2, accounting for approximately 80% of USH2.
evidence:
- reference: PMID:32995707
reference_title: "Usher syndrome: clinical features, molecular genetics and advancing therapeutics."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "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."
explanation: Documents USH2A as the predominant USH2 gene, accounting for approximately 80% of type 2.
- name: ADGRV1 Mutations
association: Causative
subtype: USH2
gene_term:
preferred_term: ADGRV1
term:
id: hgnc:17416
label: ADGRV1
features: >
Biallelic pathogenic variants in ADGRV1 cause Usher syndrome type 2C.
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of three genes – ADGRV1, USH2A, or WHRN – establishes the diagnosis if clinical features are inconclusive."
explanation: Confirms ADGRV1 as one of the three established USH2 genes.
- name: WHRN Mutations
association: Causative
subtype: USH2
gene_term:
preferred_term: WHRN
term:
id: hgnc:16361
label: WHRN
features: >
Biallelic pathogenic variants in WHRN cause Usher syndrome type 2D.
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of three genes – ADGRV1, USH2A, or WHRN – establishes the diagnosis if clinical features are inconclusive."
explanation: Confirms WHRN as one of the three established USH2 genes.
- name: CLRN1 Mutations
association: Causative
subtype: USH3
gene_term:
preferred_term: CLRN1
term:
id: hgnc:12605
label: CLRN1
features: >
Biallelic mutations in CLRN1 (clarin-1) cause Usher syndrome type 3A.
evidence:
- reference: PMID:11524702
reference_title: "Mutations in a novel gene with transmembrane domains underlie Usher syndrome type 3."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "USH3, the candidate gene that we \nidentified, encodes a 120-amino-acid protein."
explanation: >-
Identifies the USH3 causative gene (subsequently named CLRN1/clarin-1) whose
mutations underlie Usher syndrome type 3.
- reference: PMID:11524702
reference_title: "Mutations in a novel gene with transmembrane domains underlie Usher syndrome type 3."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Usher syndrome type 3 (USH3) is an autosomal recessive disorder characterized by \nprogressive hearing loss, severe retinal degeneration, and variably present \nvestibular dysfunction, assigned to 3q21-q25."
explanation: >-
Defines USH3 (the CLRN1/clarin-1 disorder at 3q21-q25) as autosomal-recessive
hearing loss with retinal degeneration and variable vestibular dysfunction.
diagnosis:
- name: Audiologic and retinal functional evaluation
description: >-
Establish the clinical phenotype with subjective and electrophysiologic
hearing and retinal testing.
results: >-
The combination and time course of sensorineural hearing loss, retinal
dysfunction, and vestibular findings distinguish the classical USH1, USH2,
and USH3 presentations.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The diagnosis of USH1 is established in a proband with characteristic findings on electrophysiologic and subjective tests of hearing and retinal function."
explanation: GeneReviews establishes combined hearing and retinal functional testing as the clinical diagnostic route for USH1.
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The diagnosis of USH2 is established in a proband using electrophysiologic and subjective tests of hearing and retinal function."
explanation: GeneReviews establishes combined hearing and retinal functional testing as the clinical diagnostic route for USH2.
- name: Molecular genetic confirmation
description: >-
Identify biallelic pathogenic variants in an Usher-associated gene to confirm
the diagnosis or establish it when clinical features are inconclusive.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of five genes – MYO7A, USH1C, CDH23, PCDH15, and USH1G – confirms the diagnosis."
explanation: Establishes molecular confirmation for the five classic USH1 genes.
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Identification of biallelic pathogenic variants in one of three genes – ADGRV1, USH2A, or WHRN – establishes the diagnosis if clinical features are inconclusive."
explanation: Establishes molecular confirmation for the three classic USH2 genes.
treatments:
- name: Vestibular Physical Therapy
description: >
Physical therapy / vestibular rehabilitation is recommended to manage the
vestibular dysfunction and imbalance of USH1 throughout the disease course,
beginning in childhood.
therapeutic_modality: BEHAVIORAL
treatment_term:
preferred_term: physical therapy
term:
id: NCIT:C15302
label: Physical Therapy
target_phenotypes:
- preferred_term: Abnormal vestibular function
term:
id: HP:0001751
label: Abnormal vestibular function
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Physical therapy is recommended to manage vestibular dysfunction \nand imbalance throughout the disease course"
explanation: >-
GeneReviews recommends physical therapy for the vestibular dysfunction and
imbalance of USH1.
- name: Cochlear Implantation
description: >
Cochlear implantation should be considered for the severe-to-profound
sensorineural hearing loss of USH1 as young as medically feasible, typically
before age one year.
treatment_term:
preferred_term: cochlear device implantation
term:
id: NCIT:C15329
label: Surgical Procedure
target_phenotypes:
- preferred_term: Sensorineural hearing impairment
term:
id: HP:0000407
label: Sensorineural hearing impairment
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Cochlear implantation should be considered as young as medically feasible, typically before age one year."
explanation: GeneReviews recommends early cochlear implantation for the profound hearing loss of USH1.
- name: Hearing Aids
description: >
Early hearing-aid fitting is used for the hearing loss of USH2.
therapeutic_modality: DEVICE
treatment_term:
preferred_term: hearing aid usage
target_phenotypes:
- preferred_term: Sensorineural hearing impairment
term:
id: HP:0000407
label: Sensorineural hearing impairment
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Treatment of manifestations: Early fitting of hearing aids and speech training."
explanation: GeneReviews recommends early hearing-aid fitting for the hearing loss of USH2.
- name: Speech and Multimodal Communication Support
description: >-
Pair hearing technology with early speech/audioverbal therapy where auditory
communication is pursued, and offer sign language from infancy so a robust
communication modality is available before and alongside devices.
therapeutic_modality: BEHAVIORAL
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Timely audioverbal therapy following cochlear implantation is required for the development of speech."
explanation: Supports timely audioverbal therapy after implantation in USH1.
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Sign language is recommended as early as birth to stimulate communication and language development prior to hearing aids and/or cochlear implants and is used throughout life as an additional means of communication when cochlear implants are not working or accessible, or as a primary means of communication for those using a nonauditory modality."
explanation: Supports early and lifelong access to sign language rather than device-only communication.
- name: Low-Vision Rehabilitation and Psychosocial Support
description: >-
Provide orientation and adaptive-skills training as vision declines, with
school or vocational rehabilitation and recurring mental-health support for
affected people and families.
therapeutic_modality: BEHAVIORAL
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Skills for adjusting to progressive vision loss can be accessed through school, vocational rehabilitation, or training programs."
explanation: Supports adaptive and vocational rehabilitation for progressive vision loss.
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Counseling for individuals living with USH1 and family members is recommended to manage mental health throughout the disease course, beginning in childhood and again as vision loss progresses."
explanation: Supports longitudinal mental-health counseling for affected people and families.
- name: Audiologic and Ophthalmologic Surveillance
description: >-
Perform at least annual audiologic surveillance for people using hearing
aids or cochlear implants and annual multimodal retinal surveillance,
beginning before visual symptoms in USH1 and by childhood in USH2, to track
function and identify treatable complications.
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Annual audiometry and tympanometry in those with cochlear implants or hearing aids to assure adequate auditory stimulation."
explanation: Supports annual audiologic surveillance for device users.
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Annual ophthalmologic evaluation with fundus photography, visual acuity, visual field testing, electroretinography, optical coherence tomography, and fundus autofluorescence prior to the onset of visual manifestations."
explanation: Supports annual multimodal ophthalmologic surveillance before visual manifestations in USH1.
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Annual fundus photography, visual acuity, visual field, electroretinography, optical coherence tomography, and fundus autofluorescence from age ten years."
explanation: Supports annual retinal surveillance from age ten in USH2.
- name: Smoking Avoidance and Sunlight Protection
description: >-
Counsel against tobacco smoking and recommend sunglasses and a cap to limit
bright-light exposure as modifiable precautions for retinitis pigmentosa.
therapeutic_modality: BEHAVIORAL
target_phenotypes:
- preferred_term: Rod-cone dystrophy
term:
id: HP:0000510
label: Rod-cone dystrophy
evidence:
- reference: PMID:20301442
reference_title: "Usher Syndrome Type I."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Exposure to bright sunlight and smoking tobacco can accelerate progression of RP. Refrain from smoking and avoid exposing eyes to sunlight by wearing sunglasses and a cap."
explanation: GeneReviews supports smoking avoidance and sunlight protection as precautions intended to limit RP progression.
- name: Genetic Counseling
description: >
Genetic counseling addresses the autosomal recessive recurrence risk and
informs reproductive decision-making.
treatment_term:
preferred_term: Genetic Counseling
term:
id: NCIT:C15240
label: Genetic Counseling
evidence:
- reference: PMID:20301515
reference_title: "Usher Syndrome Type II."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "USH2 is inherited in an autosomal recessive manner. Each subsequent pregnancy of a couple who have had a child with Usher syndrome type II has a 25% chance of resulting in an affected child"
explanation: Supports genetic counseling for the autosomal recessive recurrence risk of Usher syndrome.
- name: Gene Therapy
description: >
Investigational gene-replacement, gene-editing, and antisense-oligonucleotide
approaches target retinal degeneration; these approaches remain investigational.
treatment_term:
preferred_term: Gene Therapy
term:
id: NCIT:C15238
label: Gene Therapy
evidence:
- reference: PMID:32995707
reference_title: "Usher syndrome: clinical features, molecular genetics and advancing therapeutics."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "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."
explanation: Documents the investigational gene-replacement/editing/ASO strategies targeting the retinal degeneration, none yet approved.
- name: Ultevursen (QR-421a)
description: >-
Investigational antisense oligonucleotide (AON) that induces skipping of
USH2A exon 13, which contains the recurrent c.2299delG and c.2276G>T
pathogenic variants. Exon skipping is intended to produce a shortened
usherin protein. Preclinical zebrafish and patient-derived
photoreceptor-precursor studies support the splice-modulation concept; ultevursen is being
evaluated by intravitreal injection in the Phase 2b LUNA trial.
therapeutic_modality: ANTISENSE_OLIGONUCLEOTIDE
aso_details:
aso_mechanism: SPLICE_MODULATION_EXON_SKIPPING
target_gene:
preferred_term: USH2A
term:
id: hgnc:12601
label: USH2A
target_transcript: USH2A pre-mRNA
target_exon: exon 13
conjugation: UNCONJUGATED
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
target_mechanisms:
- target: Usher Protein Complex Loss of Function
treatment_effect: MODULATES
description: >-
In the USH2A exon-13 molecular subgroup, QR-421a induces exon 13 skipping
upstream of tissue-level auditory and retinal consequences; this does not
assert restored human protein-complex function or clinical efficacy.
evidence:
- reference: PMID:33895329
reference_title: Antisense oligonucleotide-based treatment of retinitis pigmentosa caused by USH2A exon 13 mutations.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Lead candidate QR-421a induced a concentration-dependent exon 13 skipping in
induced pluripotent stem cell (iPSC)-derived photoreceptor precursors from an
Usher syndrome patient homozygous for the c.2299delG mutation.
explanation: Directly supports splice modulation in patient-derived photoreceptor precursors, scoped to USH2A exon 13.
evidence:
- reference: PMID:33895329
reference_title: Antisense oligonucleotide-based treatment of retinitis pigmentosa caused by USH2A exon 13 mutations.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Mutations in USH2A are among the most common causes of syndromic and
non-syndromic retinitis pigmentosa (RP). The two most recurrent
mutations in USH2A, c.2299delG and c.2276G > T, both reside in exon 13.
explanation: >-
Establishes exon 13 as the site of the two most common USH2A pathogenic
variants, the rationale for an exon-13-skipping therapeutic strategy.
- reference: PMID:33895329
reference_title: Antisense oligonucleotide-based treatment of retinitis pigmentosa caused by USH2A exon 13 mutations.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Lead candidate QR-421a induced a concentration-dependent exon 13 skipping in
induced pluripotent stem cell (iPSC)-derived photoreceptor precursors from an
Usher syndrome patient homozygous for the c.2299delG mutation.
explanation: >-
Patient-derived photoreceptor-precursor evidence directly supports
QR-421a-mediated USH2A exon 13 skipping; it does not establish clinical efficacy.
- reference: clinicaltrials:NCT06627179
reference_title: A Two-Year Double-masked, Randomized, Sham-Controlled Study to Evaluate the Efficacy, Safety and Tolerability of Ultevursen in Subjects With Retinitis Pigmentosa (RP) Due to Mutations in Exon 13 of the USH2A Gene
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The purpose of this Phase 2b study is to evaluate the safety and tolerability of ultevursen administered via intravitreal injection (IVT) in subjects with Retinitis Pigmentosa (RP) due to mutations in exon 13 of the USH2A gene.
explanation: >-
Registry record for the ongoing LUNA trial confirms Phase 2b evaluation,
intravitreal administration, and the USH2A exon-13 molecular scope.
clinical_trials:
- name: NCT06591793
phase: PHASE_I
status: RECRUITING
description: >-
Open-label Phase 1/2 dose-escalation study of a single subretinal injection
of dual-AAV8 MYO7A gene therapy (AAVB-081) in people with USH1B retinitis
pigmentosa. The schema records this combined Phase 1/2 study as PHASE_I.
Registry status checked 2026-08-11.
evidence:
- reference: clinicaltrials:NCT06591793
reference_title: A Phase 1/2 Multicenter, Open-label, Dose Escalation, Safety and Efficacy Study of Subretinal Administration of Dual AAV8.MYO7A, AAVB-081 in Subjects With Usher Syndrome Type IB (USH1B) Retinitis Pigmentosa
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The purpose of the 081-101 study is to evaluate the safety and tolerability of a single subretinal injection of AAVB-081 in USH1B patients with retinitis pigmentosa due to a mutation in the MYO7A gene."
explanation: Establishes intervention, route, disease subtype, and MYO7A molecular eligibility.
- name: NCT06627179
phase: PHASE_II
status: ACTIVE_NOT_RECRUITING
description: >-
Double-masked, randomized, sham-controlled Phase 2b LUNA study of
intravitreal ultevursen in 81 participants with retinitis pigmentosa due to
USH2A exon 13 mutations. Registry status checked 2026-08-11.
evidence:
- reference: clinicaltrials:NCT06627179
reference_title: A Two-Year Double-masked, Randomized, Sham-Controlled Study to Evaluate the Efficacy, Safety and Tolerability of Ultevursen in Subjects With Retinitis Pigmentosa (RP) Due to Mutations in Exon 13 of the USH2A Gene
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "This is a multicenter Double-masked, Randomized, Sham-controlled study which will enroll 81 subjects."
explanation: Establishes the LUNA design and planned enrollment.
animal_models:
- name: Pdzd7 interaction zebrafish model
species: Zebrafish (Danio rerio)
genotype: Pdzd7 knockdown alone and in combination with ush2a or gpr98 perturbation
category: Knockdown interaction model
description: >-
Pdzd7 knockdown produces an Usher-like phenotype and worsens retinal-cell
death when combined with ush2a or gpr98 perturbation. It supports genetic
interaction and retinal-modifier biology but does not reproduce the full
human auditory-retinal disease or distinguish all classical subtypes.
associated_phenotypes:
- Retinal cell death
modeled_mechanisms:
- target: Photoreceptor Connecting Cilium Dysfunction
relationship: PARTIALLY_RECAPITULATES
fidelity: LOW
limitations: >-
Knockdown in zebrafish is a developmental perturbation and does not establish
the magnitude or clinical course of PDZD7 modification in humans.
description: >-
Combined perturbation changes retinal-cell survival and Gpr98 localization
near the photoreceptor connecting cilium.
evidence:
- reference: PMID:20440071
reference_title: "PDZD7 is a modifier of retinal disease and a contributor to digenic Usher syndrome."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "Pdzd7 knockdown produced an Usher-like phenotype in zebrafish, exacerbated retinal cell death in combination with ush2a or gpr98, and reduced Gpr98 localization in the region of the photoreceptor connecting cilium."
explanation: Directly supports the model's genetic-interaction and connecting-cilium readouts.
evidence:
- reference: PMID:20440071
reference_title: "PDZD7 is a modifier of retinal disease and a contributor to digenic Usher syndrome."
supports: SUPPORT
evidence_source: MODEL_ORGANISM
snippet: "We validated the human genotypes using zebrafish, and our findings were consistent with digenic inheritance of PDZD7 and GPR98, and with PDZD7 as a retinal disease modifier in patients with USH2A."
explanation: Supports use of the zebrafish experiment to test digenic and modifier hypotheses.
datasets:
- accession: ega:EGAS00001002008
title: HipSci HumanExome BeadChip analysis - Usher syndrome and congenital eye defects
description: The HipSci project brings together diverse constituents in genomics, proteomics, cell biology and clinical genetics to create a UK national iPS cell resource and use it to carry out cellular genetic studies. In this sub-study we performed Genotyping analysis using the Infinium HumanExome BeadChip on iPS cells generated from skin biopsies or blood samples from rare disease patients diagnosed with Usher syndrome and congenital eye defects.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
notes: 'European Genome-phenome Archive study, matched because the disease is named in the study''s own title ("Usher Syndrome"); description-level mentions were not accepted. EGA study_type: Other. Controlled access -- data require a Data Access Agreement. EGA metadata retrieved 2026-08-01.'
- accession: ega:EGAS00001002023
title: HipSci HumanHT 12 Expression BeadChip analysis - Usher syndrome and congenital eye defects
description: The HipSci project brings together diverse constituents in genomics, proteomics, cell biology and clinical genetics to create a UK national iPS cell resource and use it to carry out cellular genetic studies. In this sub-study we performed Expression analysis using the Illumina HumanHT -12 Expression BeadChip on iPS cells generated from skin biopsies or blood samples from rare disease patients diagnosed with Usher syndrome and congenital eye defects.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
notes: 'European Genome-phenome Archive study, matched because the disease is named in the study''s own title ("Usher Syndrome"); description-level mentions were not accepted. EGA study_type: Other. Controlled access -- data require a Data Access Agreement. EGA metadata retrieved 2026-08-01.'
- accession: ega:EGAS00001002037
title: HipSci Illumina Methylation analysis - Usher syndrome and congenital eye defects
description: The HipSci project brings together diverse constituents in genomics, proteomics, cell biology and clinical genetics to create a UK national iPS cell resource and use it to carry out cellular genetic studies. In this sub-study we performed Methylation analysis using the Infinium Methylation BeadChip on iPS cells generated from skin biopsies or blood samples from rare disease patients diagnosed with Usher syndrome and congenital eye defects.
organism:
preferred_term: human
term:
id: NCBITaxon:9606
label: Homo sapiens
notes: 'European Genome-phenome Archive study, matched because the disease is named in the study''s own title ("Usher Syndrome"); description-level mentions were not accepted. EGA study_type: Other. Controlled access -- data require a Data Access Agreement. EGA metadata retrieved 2026-08-01.'
review_notes: >-
The 2026 re-review separates auditory hair-bundle and retinal periciliary
mechanisms rather than treating one tissue defect as causally downstream of
the other. All retained causal edges now carry claim-level evidence, and the
photoreceptor-trafficking model is explicitly provisional where the cited
mouse data say "suggests." Diagnosis, communication and low-vision support,
surveillance, current gene/antisense trials, and a primary zebrafish modifier
model were added. The record retains the classical USH1/USH2/USH3 framework
while acknowledging PDZD7-associated modifier/digenic observations; it does
not promote sparsely reported extra-sensory findings to core phenotypes without
directly scoped evidence.
Question: You are an expert researcher providing comprehensive, well-cited information.
Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies
Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.
Please provide a comprehensive research report on Usher Syndrome covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.
For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.
Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed
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Search first: CTD, PubMed, PheGenI, GxE databases
Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC
For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities
For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype
Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
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Search first: PubMed, Gene Ontology, Reactome
Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types
Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
Search first: OMIM, Orphanet, HPO, PubMed
Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.
Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
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Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease
This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details
Due to token budget limitations, I must provide a summary report indicating that comprehensive data collection has been initiated. The full comprehensive report requested would require significantly more tool calls and analysis than can be completed within current constraints. Below is a partial preliminary report based on the evidence gathered thus far:
Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy and represents the most common genetic cause of deaf-blindness worldwide (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2, delmaghani2022thegeneticand pages 1-2). The syndrome is clinically characterized by the combination of sensorineural hearing loss (SNHL), progressive vision loss due to rod-cone dystrophy or retinitis pigmentosa (RP), and variable vestibular dysfunction (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2, delmaghani2022thegeneticand pages 1-2, toms2020ushersyndromeclinical pages 1-2).
The disease was first described in 1858 by German ophthalmologist Albrecht von Graefe, but was named after Scottish ophthalmologist Charles Howard Usher, who in 1914 presented a comprehensive series of 69 affected patients from 40 families (castiglione2022ushersyndrome pages 1-2, delmaghani2022thegeneticand pages 1-2).
While specific MONDO IDs were not explicitly provided in the gathered literature, the following identifiers are documented:
OMIM IDs:
- USH1B (MYO7A): #276900 / Gene #276903
- USH1C (USH1C): #276904 / Gene #605242
- USH1D (CDH23): #601067 / Gene #605516
- USH1F (PCDH15): #602083 / Gene #605514
- USH1G (USH1G/SANS): #606943 / Gene #607696
- USH2A (USH2A): #276901 / Gene #608400
- USH2C (ADGRV1): #605472 / Gene #602851
- USH2D (WHRN): #611383 / Gene #607928
- USH3A (CLRN1): #276902 / Gene #606397
(fustergarcia2021ushersyndromegenetics pages 1-2, toms2020ushersyndromeclinical pages 1-2, french2020areviewof pages 1-2)
Orphanet: The literature mentions Orphanet as a key resource but specific Orphanet ORPHA codes were not provided in the extracted text segments.
ICD Codes: Not explicitly mentioned in the gathered evidence, though the syndrome would fall under categories for hereditary retinal dystrophies and syndromic hearing loss.
The information presented is derived from aggregated disease-level resources, including peer-reviewed publications, genetic databases (OMIM, ClinVar), disease registries (Target 5000 Irish IRD registry), and population-based studies, rather than individual patient-level EHR data (delmaghani2022thegeneticand pages 1-2, stephenson2023ushersyndromeon pages 1-2, karali2022geneticepidemiologyof pages 1-2).
Genetic Causes:
Usher syndrome is primarily a monogenic, autosomal recessive disorder, though complex inheritance patterns including digenic forms have been reported (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2, whatley2020ushersyndromegenetics pages 1-2). To date, nine genes have been confirmed as causative when mutated: MYO7A, USH1C, CDH23, PCDH15, and USH1G (SANS) for Usher type 1; USH2A, ADGRV1, and WHRN for Usher type 2; and CLRN1 for Usher type 3 (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2, delmaghani2022thegeneticand pages 1-2).
A tenth gene, CIB2, was previously proposed but has been excluded by recent expert consensus (castiglione2022ushersyndrome pages 1-2, guimaraes2023inheritedcausesof pages 1-6).
The encoded proteins form a dynamic network called the "Usher interactome" that is essential for the development and maintenance of stereocilia in cochlear hair cells and for protein trafficking and structural integrity at the periciliary region of retinal photoreceptors (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2, delmaghani2022thegeneticand pages 1-2).
| USH Type | Gene symbol | Protein name | Chromosome location (GRCh38) | Disease / subtype OMIM ID | Protein / gene function | Reported mutation frequency / prevalence contribution |
|---|---|---|---|---|---|---|
| USH1 | MYO7A | Myosin VIIA | chr11:77128246–77215241 | USH1B / 276900; gene 276903 | Actin-based motor protein essential for hair-bundle structure/function and photoreceptor/periciliary transport | Major USH1 gene; reported to account for >50% of USH1 in one review; also listed as 21% of all genetically characterized USH cases in a large cohort summary (toms2020ushersyndromeclinical pages 1-2, french2020areviewof pages 1-2) |
| USH1 | USH1C | Harmonin | chr11:17493895–17544416 | USH1C / 276904; gene 605242 | Scaffold protein in the Usher interactome; organizes protein complexes in stereocilia and photoreceptors | Rare cause; estimated ~2% of all USH cases in a cohort summary (french2020areviewof pages 1-2) |
| USH1 | CDH23 | Cadherin 23 | chr10:71396934–71815947 | USH1D / 601067; gene 605516 | Cell-adhesion protein; component of stereociliary links important for mechanotransduction | Uncommon cause; estimated ~6% of all USH cases in a cohort summary (french2020areviewof pages 1-2) |
| USH1 | PCDH15 | Protocadherin 15 | chr10:53802771–55627942 | USH1F / 602083; gene 605514 | Cell-adhesion / tip-link associated protein required for stereocilia cohesion and sensory transduction | Uncommon cause; estimated ~3% of all USH cases in a cohort summary (french2020areviewof pages 1-2) |
| USH1 | USH1G | SANS | chr17:73223675–73258264 | USH1G / 606943; gene 607696 | Scaffold/adaptor protein within the Usher protein network in hair cells and photoreceptors | Very rare; estimated ~1% of all USH cases in a cohort summary (french2020areviewof pages 1-2) |
| USH2 | USH2A | Usherin | chr1:215622891–216423448 | USH2A / 276901; gene 608400 | Extracellular matrix / transmembrane-associated Usher complex component at photoreceptor periciliary membrane and base of hair bundles | Principal USH2 gene; reported to cause ~80% of USH2 in one review, 50% of all USH cases in another cohort summary, and 50% of all USH2 cases in a focused USH2 review (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3, french2020areviewof pages 1-2) |
| USH2 | ADGRV1 | Adhesion G protein-coupled receptor V1 (VLGR1) | chr5:89942634–90549316 | USH2C / 605472; gene 602851 | Very large adhesion GPCR; part of the USH2 complex in hair bundles and photoreceptor periciliary region | Less common USH2 cause; estimated ~5% of all USH cases in a cohort summary (french2020areviewof pages 1-2) |
| USH2 | WHRN | Whirlin | chr9:117382790–117481605 | USH2D / 611383; gene 607928 | PDZ-domain scaffold protein in the USH2 complex; supports stereocilia elongation/organization and photoreceptor protein networks | Rare USH2 cause; estimated ~0.4% of all USH cases in a cohort summary (french2020areviewof pages 1-2) |
| USH3 | CLRN1 | Clarin-1 | chr3:150928506–150975693 | USH3A / 276902; gene 606397 | Four-transmembrane protein implicated in hair-cell and photoreceptor synaptic/sensory function | Main confirmed USH3 gene; estimated ~2% of all USH cases overall, but markedly enriched in Finnish and Ashkenazi Jewish populations where >40% of USH can be USH3 (subtype prevalence, not gene share) (guimaraes2023inheritedcausesof pages 1-6, french2020areviewof pages 1-2) |
| Contested / no longer generally accepted as confirmed | CIB2 | Calcium and integrin-binding family member 2 | — | Formerly proposed USH1J / gene 605564 | Initially proposed Usher-related protein; later reviews note it is no longer generally considered a confirmed Usher gene | Included in some older 10-gene lists, but multiple reviews caution against counting it among confirmed causative genes (castiglione2022ushersyndrome pages 1-2, guimaraes2023inheritedcausesof pages 1-6) |
Table: This table summarizes the confirmed major Usher syndrome genes by clinical subtype, with protein names, genomic locations, OMIM identifiers, core functions, and reported contribution to disease burden. It is useful for quickly comparing the relative importance and biological roles of USH1, USH2, and USH3 genes.
Mechanistic Basis:
In the inner ear, Usher proteins are critical for the correct development and maintenance of the structure and cohesion of stereocilia—the mechanosensitive organelles on auditory and vestibular hair cells. Disease-causing mutations destabilize the tip links that bind stereocilia together and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanotransduction of sound waves into electrical signals (fustergarcia2021ushersyndromegenetics pages 1-2, whatley2020ushersyndromegenetics pages 1-2).
In the retina, the Usher protein network localizes principally to the periciliary region of photoreceptors and plays an important role in maintaining periciliary structure and trafficking molecules between the inner and outer segments of photoreceptors. Disruption of these processes leads to progressive photoreceptor degeneration characteristic of retinitis pigmentosa (fustergarcia2021ushersyndromegenetics pages 1-2, delmaghani2022thegeneticand pages 1-2).
Genetic Risk Factors:
Autosomal recessive inheritance: Both parents must be carriers (heterozygous) for a child to be affected (homozygous or compound heterozygous). Carrier frequency is elevated in populations with consanguinity or founder effects (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2).
Founder effects: Certain populations show enrichment of specific USH mutations. For example, USH3 (CLRN1 mutations) is particularly prevalent in Finnish and Ashkenazi Jewish populations, where it accounts for >40% of USH cases, compared to 1-6% in other populations (guimaraes2023inheritedcausesof pages 1-6, french2020areviewof pages 1-2).
Modifier genes: PDZD7 has been identified as a modifier gene that can aggravate the phenotype when present with mutations in USH2 genes (USH2A, ADGRV1, WHRN), though it is not independently causative (castiglione2022ushersyndrome pages 1-2, french2020areviewof pages 1-2).
Digenic inheritance: Rare cases of digenic inheritance involving mutations in two different USH genes or a USH gene plus PDZD7 have been reported in mice and humans (whatley2020ushersyndromegenetics pages 1-2).
Environmental Risk Factors:
Limited evidence exists for environmental risk factors in Usher syndrome as it is primarily a genetic disorder. However:
Light exposure has been shown in animal models to exacerbate photoreceptor degeneration, suggesting that bright light may accelerate vision loss (fustergarcia2021ushersyndromegenetics pages 1-2).
Consanguinity increases risk of autosomal recessive conditions including USH in offspring (fustergarcia2021ushersyndromegenetics pages 1-2).
Genetic Protective Factors:
No clearly defined protective genetic variants have been identified in the gathered literature. However:
Environmental Protective Factors:
No specific environmental protective factors have been definitively established. Potential areas for consideration include:
Early auditory intervention (hearing aids, cochlear implants) and visual aids may slow functional decline and improve quality of life, though they do not alter the underlying pathophysiology (castiglione2022ushersyndrome pages 1-2, toms2020ushersyndromeclinical pages 1-2, french2020areviewof pages 1-2).
Avoidance of excessive light exposure may theoretically reduce photostress and slow retinal degeneration, based on animal model data, though clinical evidence is lacking (fustergarcia2021ushersyndromegenetics pages 1-2).
Direct gene-environment interaction studies are scarce in the USH literature reviewed. The primary gene-environment consideration relates to:
Usher syndrome is traditionally classified into three clinical subtypes (USH1, USH2, USH3) based on the severity and onset of hearing loss, presence or absence of vestibular dysfunction, and age at onset of retinitis pigmentosa (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2, delmaghani2022thegeneticand pages 1-2, toms2020ushersyndromeclinical pages 1-2).
| Usher subtype | Sensorineural hearing loss (onset / severity / progression) | Retinitis pigmentosa / visual features | Vestibular function | Age of onset summary | Key distinguishing features | Suggested HPO terms |
|---|---|---|---|---|---|---|
| USH1 | Congenital, severe-to-profound, usually prelingual SNHL; often described as non-progressive or minimally progressive in classic presentations (toms2020ushersyndromeclinical pages 1-2, delmaghani2022thegeneticand pages 2-4) | Prepubertal / first-decade onset rod-cone dystrophy or RP; progressive night blindness, peripheral visual field constriction, later severe visual impairment/legal blindness often by the fourth decade in classic descriptions (toms2020ushersyndromeclinical pages 1-2, delmaghani2022thegeneticand pages 2-4) | Vestibular areflexia / marked hypofunction is typical; delayed motor milestones, many children walking after 18 months (toms2020ushersyndromeclinical pages 1-2, delmaghani2022thegeneticand pages 2-4) | Hearing: birth; Vision: first decade / prepubertal; Balance: infancy (toms2020ushersyndromeclinical pages 1-2, delmaghani2022thegeneticand pages 2-4) | Most severe classic form; congenital deafness plus early RP and absent vestibular function; speech may not develop without early auditory intervention such as cochlear implantation (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6) | HP:0000407 Sensorineural hearing impairment; HP:0000369 Progressive deafness; HP:0000510 Visual impairment; HP:0000556 Retinal dystrophy; HP:0000662 Night blindness; HP:0001123 Constriction of visual field; HP:0001756 Vestibular dysfunction; HP:0002194 Delayed gross motor development |
| USH2 | Congenital/early-onset, moderate-to-severe, classically down-sloping high-frequency SNHL; speech generally intelligible; once considered stable, but multiple studies report progression, especially at high frequencies (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3, delmaghani2022thegeneticand pages 2-4) | Second-decade onset RP; progressive nyctalopia and concentric visual field loss; average diagnosis often in the third decade; cataract and cystoid macular edema are relatively common in USH cohorts (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6, stephenson2023ushersyndromeon pages 1-2) | Usually normal vestibular function, though some series report variable or subtle dysfunction in a subset (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3, delmaghani2022thegeneticand pages 2-4) | Hearing: birth/early childhood; Vision: second decade; Balance: usually normal (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3) | Most common subtype; milder auditory phenotype than USH1, later retinal disease, and absent/less prominent vestibular signs; often associated with USH2A (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3, french2020areviewof pages 1-2) | HP:0000407 Sensorineural hearing impairment; HP:0001329 High-frequency sensorineural hearing impairment; HP:0000510 Visual impairment; HP:0000556 Retinal dystrophy; HP:0000662 Night blindness; HP:0001123 Constriction of visual field; HP:0000545 Myopia; HP:0000518 Cataract |
| USH3 | Postlingual, progressive, variable SNHL; hearing may be normal or near-normal in early life, then worsens over time to severe/profound deafness in many affected individuals (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6, delmaghani2022thegeneticand pages 2-4) | Variable onset, often postpubertal or in the second decade, with progressive RP causing nyctalopia and visual field constriction (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6) | Variable vestibular dysfunction, present in about half of affected individuals in some summaries (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6) | Hearing: childhood to adolescence, postlingual; Vision: variable, often second decade or later; Balance: variable onset (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6) | Rarest classic subtype in many Western populations; characterized chiefly by progressive rather than congenital-fixed auditory loss and marked intrafamilial/interindividual variability (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6, delmaghani2022thegeneticand pages 2-4) | HP:0000407 Sensorineural hearing impairment; HP:0000369 Progressive deafness; HP:0000510 Visual impairment; HP:0000556 Retinal dystrophy; HP:0000662 Night blindness; HP:0001123 Constriction of visual field; HP:0001756 Vestibular dysfunction |
Table: This table summarizes the defining clinical phenotypes of USH1, USH2, and USH3, including hearing, retinal, and vestibular features, timing of onset, and distinguishing traits. It also provides suggested HPO terms to support phenotype annotation in a disease knowledge base.
Hearing Loss: - Type: Sensorineural hearing loss (SNHL) - Onset: Congenital, present at birth (prelingual) - Severity: Severe to profound - Progression: Classically described as non-progressive or minimally progressive - Frequency: Present in 100% of USH1 patients - Impact on QOL: Profound; without early intervention (hearing aids, cochlear implants), speech development is severely impaired - HPO terms: HP:0000407 (Sensorineural hearing impairment), HP:0008527 (Congenital sensorineural hearing impairment), HP:0000369 (Progressive deafness - for rare progressive cases) (toms2020ushersyndromeclinical pages 1-2, delmaghani2022thegeneticand pages 2-4)
Retinitis Pigmentosa: - Type: Rod-cone dystrophy - Onset: Prepubertal, typically within the first decade of life - Progression: Progressive; legal blindness often by the fourth decade - Severity: Severe - Frequency: Present in 100% of USH1 patients - Key findings: Night blindness (nyctalopia), peripheral visual field constriction (tunnel vision), bone-spicule pigmentation on fundoscopy - HPO terms: HP:0000510 (Visual impairment), HP:0000556 (Retinal dystrophy), HP:0000662 (Night blindness), HP:0001123 (Constriction of visual field), HP:0000580 (Pigmentary retinopathy) (toms2020ushersyndromeclinical pages 1-2, delmaghani2022thegeneticand pages 2-4)
Vestibular Dysfunction: - Type: Bilateral vestibular areflexia - Onset: Congenital/infancy - Severity: Severe, absent vestibular responses - Frequency: Present in most/all USH1 patients - Key findings: Delayed motor milestones, most children do not walk before 18 months of age - HPO terms: HP:0001756 (Vestibular dysfunction), HP:0002194 (Delayed gross motor development), HP:0002510 (Areflexia of the lower limbs - vestibular context) (toms2020ushersyndromeclinical pages 1-2, delmaghani2022thegeneticand pages 2-4)
Hearing Loss: - Type: Sensorineural hearing loss - Onset: Congenital or early childhood - Severity: Moderate to severe, typically with a down-sloping audiogram (higher frequencies more affected) - Progression: Previously considered stable, but recent studies document progressive hearing loss, especially at high frequencies - Frequency: Present in 100% of USH2 patients - Speech: Generally intelligible - Impact on QOL: Moderate to severe; speech is usually preserved with hearing aids - HPO terms: HP:0000407 (Sensorineural hearing impairment), HP:0001329 (High-frequency sensorineural hearing impairment) (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3, delmaghani2022thegeneticand pages 2-4)
Retinitis Pigmentosa: - Onset: Second decade of life - Progression: Progressive; average age of diagnosis in third decade; cataract and cystoid macular edema are relatively common (present in >50% in some cohorts) - Frequency: Present in 100% of USH2 patients - Key findings: Night blindness, concentric visual field loss, myopia is common, cataracts - HPO terms: HP:0000556 (Retinal dystrophy), HP:0000662 (Night blindness), HP:0001123 (Constriction of visual field), HP:0000545 (Myopia), HP:0000518 (Cataract), HP:0007754 (Cystoid macular edema) (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6, stephenson2023ushersyndromeon pages 1-2)
Vestibular Function: - Typically normal, though some studies report variable or subtle vestibular dysfunction in a subset of patients - HPO term: HP:0002403 (Normal vestibular function - for majority), HP:0001756 (Vestibular dysfunction - for variant presentations) (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3, delmaghani2022thegeneticand pages 2-4)
Hearing Loss: - Type: Sensorineural hearing loss - Onset: Postlingual, variable (childhood to adolescence) - Severity: Progressive, ranging from mild to profound over time - Progression: Progressive; many individuals develop severe to profound deafness - Frequency: Present in 100% of USH3 patients - Speech: Normal early development, but may deteriorate with progressive hearing loss - HPO terms: HP:0000407 (Sensorineural hearing impairment), HP:0000369 (Progressive deafness) (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6, delmaghani2022thegeneticand pages 2-4)
Retinitis Pigmentosa: - Onset: Variable, often postpubertal or in the second decade - Progression: Progressive - Frequency: Present in 100% of USH3 patients - HPO terms: HP:0000556 (Retinal dystrophy), HP:0000662 (Night blindness), HP:0001123 (Constriction of visual field) (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6)
Vestibular Function: - Variable; vestibular dysfunction present in approximately 50% of affected individuals - HPO term: HP:0001756 (Vestibular dysfunction) (toms2020ushersyndromeclinical pages 1-2, guimaraes2023inheritedcausesof pages 1-6)
Emerging evidence suggests additional comorbidities beyond the classic triad:
Nine genes are confirmed as causative of Usher syndrome when mutated (fustergarcia2021ushersyndromegenetics pages 1-2, castiglione2022ushersyndrome pages 1-2, delmaghani2022thegeneticand pages 1-2):
USH1 Genes: - MYO7A (OMIM 276903): Encodes myosin VIIA, an actin-based motor protein - USH1C (OMIM 605242): Encodes harmonin, a scaffold protein - CDH23 (OMIM 605516): Encodes cadherin 23, a cell-adhesion protein - PCDH15 (OMIM 605514): Encodes protocadherin 15, a cell-adhesion protein - USH1G (OMIM *607696): Encodes SANS, a scaffold protein
USH2 Genes: - USH2A (OMIM 608400): Encodes usherin, an extracellular matrix protein - ADGRV1 (OMIM 602851): Encodes adhesion GPCR V1 (VLGR1) - WHRN (OMIM *607928): Encodes whirlin, a PDZ-domain scaffold protein
USH3 Gene: - CLRN1 (OMIM *606397): Encodes clarin-1, a four-transmembrane protein
(See artifact-00 for comprehensive gene table)
Major genes and mutation frequencies:
MYO7A: Accounts for >50% of USH1 cases and ~21% of all genetically characterized USH cases. Both missense and truncating mutations have been identified (toms2020ushersyndromeclinical pages 1-2, french2020areviewof pages 1-2).
USH2A: The most frequently mutated USH gene overall, responsible for approximately 80% of USH2 cases and ~50% of all USH cases in some cohorts. It is also the most common cause of autosomal recessive non-syndromic RP (toms2020ushersyndromeclinical pages 1-2, stemerdink2022geneticspathogenesisand pages 1-3, french2020areviewof pages 1-2, karali2022geneticepidemiologyof pages 1-2). The variant c.2299delG in USH2A is particularly prevalent, with frequencies as high as 77.5% in some USH2 cohorts, likely representing an ancestral mutation (guimaraes2023inheritedcausesof pages 1-6).
ADGRV1: Accounts for ~5% of all USH cases (french2020areviewof pages 1-2).
CDH23: Accounts for ~6% of all USH cases (french2020areviewof pages 1-2).
Other genes (USH1C, PCDH15, USH1G, WHRN, CLRN1) individually account for ≤3% of all USH cases, with some genes being very rare except in specific populations (e.g., CLRN1 in Finnish and Ashkenazi Jewish populations) (guimaraes2023inheritedcausesof pages 1-6, french2020areviewof pages 1-2).
Variant classification:
Variants are classified according to ACMG/AMP guidelines as pathogenic, likely pathogenic, or variants of uncertain significance (VUS). In one large Italian IRD cohort, ABCA4 was the most frequently mutated gene (26.3% of solved cases), followed by USH2A (11.2%, n=228 patients), indicating the high contribution of USH2A to the overall IRD burden (karali2022geneticepidemiologyof pages 1-2).
Variant types:
Pathogenic variants in USH genes include: - Missense mutations (single amino acid substitutions) - Nonsense mutations (premature stop codons) - Frameshift mutations (insertions/deletions causing reading frame shifts) - Splice-site mutations (affecting mRNA splicing) - Large deletions/duplications (structural variants)
Almost half of identified variants in recent cohorts are novel, highlighting ongoing genetic heterogeneity (fustergarcia2021ushersyndromegenetics pages 1-2).
Allele frequencies:
Population-specific allele frequencies vary. The c.2299delG variant in USH2A is notably common in USH2 patients but rare in the general population. A comparison of disease prevalence to genetic prevalence calculated from gnomAD allele frequencies showed general correlation but some discordance, suggesting that certain presumed pathogenic variants may be nonpathogenic or hypomorphic (hanany2024comparisonofworldwide pages 1-2).
Somatic vs. germline:
Usher syndrome is a germline disorder; all causative variants are inherited or arise de novo in the germline, not somatically acquired.
Functional consequences:
PDZD7 is a recognized modifier gene that can exacerbate the USH2 phenotype when mutated in combination with USH2A, ADGRV1, or WHRN mutations, but is not independently causative (castiglione2022ushersyndrome pages 1-2, french2020areviewof pages 1-2).
No specific epigenetic modifications (DNA methylation, histone modifications) were detailed in the gathered USH literature, though this remains an area for further investigation.
Usher syndrome is not typically associated with large-scale chromosomal abnormalities (aneuploidies, translocations, inversions). It is caused by sequence-level mutations in specific genes.
Usher syndrome is overwhelmingly a genetic disorder with minimal documented environmental contributions to disease causation. However, environmental factors may modulate disease progression:
No specific infectious agents, toxins, radiation, pollution, or occupational exposures have been implicated in USH etiology.
This report represents a preliminary summary based on initial literature retrieval. The comprehensive, full-scale report requested covering all 15 sections (Disease Information, Etiology, Phenotypes, Genetic/Molecular Information, Environmental Information, Mechanism/Pathophysiology, Anatomical Structures, Temporal Development, Inheritance and Population, Diagnostics, Outcome/Prognosis, Treatment, Prevention, Other Species/Natural Disease, and Model Organisms) with complete citations, ontology terms, direct quotes from abstracts, and detailed tables would require substantial additional tool calls, evidence gathering, artifact creation, and synthesis that exceed current token and time constraints.
For a full comprehensive report suitable for populating a disease knowledge base, additional work is needed to: - Gather detailed mechanistic and pathophysiology information with GO terms - Identify anatomical structures with UBERON and Cell Ontology terms - Research temporal development, disease stages, and natural history - Collect inheritance patterns, penetrance, expressivity, and epidemiology data with specific prevalence/incidence figures - Detail diagnostic approaches including genetic testing strategies, biomarkers, and clinical criteria - Compile outcome and prognosis information including survival rates, quality of life measures - Summarize treatment modalities with MAXO terms, including ongoing clinical trials - Document prevention strategies and genetic counseling approaches - Review model organisms (mouse, zebrafish, Drosophila) with phenotype recapitulation details - Create additional comprehensive tables for variants, treatments, diagnostics, and model organisms
This preliminary report should serve as a foundation, with the understanding that comprehensive knowledge base population will require continued systematic evidence gathering and synthesis.
References
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