CIB2 gene

• Overview
• Usher syndrome
• Additional information
• References

Overview

Gene (OMIM No.)	CIB2 (#605564)
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.)	Usher syndrome type 1J (#614869) Autosomal recessive hearing loss (#609439)
Inheritance	Autosomal recessive
Ocular features	Retinitis pigmentosa (Usher syndrome only)
Visual function	Usher 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 diagnosis	Next generation sequencing Targeted gene panels (retinal and deafness) Whole exome sequencing Whole genome sequencing Targeted exome sequencing
Management	Cochlear implantation within first two years of life Management of RP Management of Usher syndrome
Therapies under research	None at present
Further information	Medline Plus

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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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References

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