CRYBA4 gene


Gene (OMIM No.)
Function of gene/protein
  • Protein: crystallin beta A4
  • Lens-specific protein with both structural and functional components
  • Highly soluble and transparent structure helps to maintain lens transparency
  • Binds to misfolded proteins to prevent aggregation
  • Inhibit apoptosis
  • Functions as a molecular chaperone in its oxidised form
Clinical phenotype
(OMIM phenotype no.)
  • Cataract 23, multiple types (#610425)
  • Autosomal dominant
Ocular features
Systemic features
  • No extraocular features have been reported
Key investigations
  • Measurement of corneal diameter
  • B-scan USS to measure axial length to document microphthalmia and detect any posterior segment abnormalities
  • Electrophysiology
  • TORCH screen
  • MRI brain and orbit
  • Assessment with a paediatrician if suspicious of systemic involvement
Molecular diagnosisNext generation sequencing
  • Targeted gene panels (cataract)
  • Whole exome sequencing
  • Whole genome sequencing
Therapies under research
  • None at present
Further information

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  1.  Billingsley G, Santhiya ST, Paterson AD, et al. CRYBA4, a novel human cataract gene, is also involved in microphthalmia. Am J Hum Genet. 2006;79(4):702‐709
  2.  Lampi KJ, Ma Z, Shih M, et al. Sequence analysis of betaA3, betaB3, and betaA4 crystallins completes the identification of the major proteins in young human lens. J Biol Chem. 1997;272(4):2268‐2275
  3.  Santhiya ST, Manisastry SM, Rawlley D, et al. Mutation analysis of congenital cataracts in Indian families: identification of SNPS and a new causative allele in CRYBB2 gene. Invest Ophthalmol Vis Sci. 2004;45(10):3599‐3607
  4.  van Rens GL, Geurts van Kessel AH, Bloemendal H. Localization of the beta A4-crystallin gene (CRYBA4) on human chromosome 22 in the region q11.2–>q13.1. Cytogenet Cell Genet. 1992;61(3):180‐183
  5.  Zhou G, Zhou N, Hu S, Zhao L, Zhang C, Qi Y. A missense mutation in CRYBA4 associated with congenital cataract and microcornea. Mol Vis. 2010;16:1019‐1024

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Updated on November 30, 2020
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