CIB2 gene


Gene (OMIM No.)
Function of gene/protein
  • Protein: Calcium and integrin binding family member 2
  • Calcium- and integrin-binding protein
  • Required for the normal development and function of the inner ear hair cell stereocilia
Clinical phenotype
(OMIM phenotype no.)
  • Autosomal recessive
Ocular features
Visual functionUsher syndrome
  • Nyctalopia with pre-adolescent onset
  • Peripheral visual field loss
  • Loss of central and colour vision in later life
Systemic features
  • Congenital, bilateral, severe to profound sensorineural hearing loss
  • Failed newborn hearing screen or hearing difficulties suspected in infancy
  • Vestibular dysfunction affecting balance from birth
Key investigations
  • Newborn hearing screen – otoacoustic emission and automated auditory brainstem response
  • Pure tone audiometry
  • Electrophysiology
  • Fundus autofluorescence (FAF): a ring of hyper-AF in the macula
  • Optical coherence tomography (OCT): progressive loss of outer retinal structures which spares the fovea initially; cystoid macular oedema may be detected
  • Kinetic perimetry
Molecular diagnosisNext generation sequencing
  • Targeted gene panels (retinal and deafness)
  • Whole exome sequencing
  • Whole genome sequencing
  • Targeted exome sequencing
Therapies under research
  • None at present
Further information

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Additional information

CIB2 mutations have been reported in families with Usher syndrome type 1J and autosomal recessive non-syndromic hearing loss (DFNB48).[1] One study reported biallelic CIB2 null variants in patients with non-syndromic recessive hearing loss (DFNB48) but with no retinal symptoms, questioning the status of CIB2 as an Usher syndrome causative gene.[2]

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  1.  Riazuddin S, Belyantseva IA, Giese APJ, et al. Alterations of the CIB2 calcium- and integrin-binding protein cause Usher syndrome type 1J and nonsyndromic deafness DFNB48. Nat Genet. 2012;44(11):1265-1271
  2.  Booth KT, Kahrizi K, Babanejad M, et al. Variants in CIB2 cause DFNB48 and not USH1J. Clin Genet. 2017

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Updated on November 30, 2020
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