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Usher syndrome type 2C(USH2C; USH2B, FORMERLY)

MedGen UID:
419359
Concept ID:
C2931213
Disease or Syndrome
Synonyms: Usher syndrome, type 2B; USHER SYNDROME, TYPE IIC
 
Genes (locations): ADGRV1 (5q14.3); PDZD7 (10q24.31)
 
Monarch Initiative: MONDO:0011558
OMIM®: 605472

Disease characteristics

Excerpted from the GeneReview: Usher Syndrome Type II
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. 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; the rate and degree of vision loss vary within and among families. [from GeneReviews]
Authors:
Robert Koenekoop  |  Moises Arriaga  |  Karmen M Trzupek, et. al.   view full author information

Additional descriptions

From OMIM
Usher syndrome is a clinically and genetically heterogeneous autosomal recessive disorder characterized by sensorineural hearing deficiencies at birth and later development of progressive retinitis pigmentosa (RP). It is the most frequent cause of combined deafness and blindness in adults and affects 3 to 6% of children born with hearing impairment. In brief, patients with Usher syndrome type II have mild hearing impairment with normal vestibular responses. Type II is the most common of the 3 Usher syndromes (Eudy et al., 1998). See 276900 for clinical characterization of Usher syndrome types I, II, and III. For a discussion of genetic heterogeneity of Usher syndrome type II, see USH2A (276901).  http://www.omim.org/entry/605472
From MedlinePlus Genetics
Usher syndrome type II is characterized by hearing loss from birth and progressive vision loss that begins in adolescence or adulthood. The hearing loss associated with this form of Usher syndrome ranges from mild to severe and mainly affects the ability to hear high-frequency sounds. For example, it is difficult for affected individuals to hear high, soft speech sounds, such as those of the letters d and t. The degree of hearing loss varies within and among families with this condition, and it may become more severe over time. Unlike the other forms of Usher syndrome, type II is not associated with vestibular abnormalities that cause difficulties with balance.

People with Usher syndrome type III experience hearing loss and vision loss beginning somewhat later in life. Unlike the other forms of Usher syndrome, type III is usually associated with normal hearing at birth. Hearing loss typically begins during late childhood or adolescence, after the development of speech, and becomes more severe over time. By middle age, most affected individuals have profound hearing loss. Vision loss caused by retinitis pigmentosa also develops in late childhood or adolescence. Some people with Usher syndrome type III develop vestibular abnormalities that cause problems with balance.

Most individuals with Usher syndrome type I are born with severe to profound hearing loss. Worsening vision loss caused by retinitis pigmentosa becomes apparent in childhood. This type of Usher syndrome also causes abnormalities of the vestibular system, which is the part of the inner ear that helps maintain the body's balance and orientation in space. As a result of the vestibular abnormalities, children with the condition have trouble with balance. They begin sitting independently and walking later than usual, and they may have difficulty riding a bicycle and playing certain sports.

Researchers have identified three major types of Usher syndrome, designated as types I, II, and III. These types are distinguished by the severity of hearing loss, the presence or absence of balance problems, and the age at which signs and symptoms appear. The types are further divided into subtypes based on their genetic cause.

Usher syndrome is a condition characterized by partial or total hearing loss and vision loss that worsens over time. The hearing loss is classified as sensorineural, which means that it is caused by abnormalities of the inner ear. The loss of vision is caused by an eye disease called retinitis pigmentosa (RP), which affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss occurs as the light-sensing cells of the retina gradually break down. Loss of night vision begins first, followed by blind spots that develop in the side (peripheral) vision. Over time, these blind spots enlarge and merge to produce tunnel vision. In some cases, vision is further impaired by clouding of the lens of the eye (cataracts). However, many people with retinitis pigmentosa retain some central vision throughout their lives.  https://medlineplus.gov/genetics/condition/usher-syndrome

Clinical features

From HPO
Congenital sensorineural hearing impairment
MedGen UID:
356101
Concept ID:
C1865866
Disease or Syndrome
A type of hearing impairment caused by an abnormal functionality of the cochlear nerve with congenital onset.
Rod-cone dystrophy
MedGen UID:
1632921
Concept ID:
C4551714
Disease or Syndrome
An inherited retinal disease subtype in which the rod photoreceptors appear to be more severely affected than the cone photoreceptors. Typical presentation is with nyctalopia (due to rod dysfunction) followed by loss of mid-peripheral field of vision, which gradually extends and leaves many patients with a small central island of vision due to the preservation of macular cones.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVUsher syndrome type 2C

Professional guidelines

Curated

Bolz HJ, Roux AF
Eur J Hum Genet 2011 Aug;19(8) Epub 2011 Mar 9 doi: 10.1038/ejhg.2011.15. PMID: 21697857Free PMC Article

Recent clinical studies

Diagnosis

Wei C, Yang L, Cheng J, Imani S, Fu S, Lv H, Li Y, Chen R, Leung EL, Fu J
BMC Med Genet 2018 Jun 11;19(1):99. doi: 10.1186/s12881-018-0602-0. PMID: 29890953Free PMC Article
Zhang N, Wang J, Liu S, Liu M, Jiang F
Ophthalmic Genet 2018 Aug;39(4):517-521. Epub 2018 Jun 8 doi: 10.1080/13816810.2018.1479430. PMID: 29883260

Prognosis

Wei C, Yang L, Cheng J, Imani S, Fu S, Lv H, Li Y, Chen R, Leung EL, Fu J
BMC Med Genet 2018 Jun 11;19(1):99. doi: 10.1186/s12881-018-0602-0. PMID: 29890953Free PMC Article

Clinical prediction guides

Wei C, Yang L, Cheng J, Imani S, Fu S, Lv H, Li Y, Chen R, Leung EL, Fu J
BMC Med Genet 2018 Jun 11;19(1):99. doi: 10.1186/s12881-018-0602-0. PMID: 29890953Free PMC Article

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