CRYBB1 gene

Overview
Congenital cataracts
Microphthalmia, anophthalmia, coloboma (MAC)
Additional information
References

Overview

Gene (OMIM No.)	CRYBB1 (#600929)
Function of gene/protein	Protein: crystallin beta B1 (CRYBB1) CRYBB1 proteins are highly soluble, lens-specific components Interact with other crystallins to help maintain lens transparency Also involved in lens development
Clinical phenotype (OMIM phenotype no.)	Cataract 17, multiple types (#611544)
Inheritance	Autosomal recessive Autosomal dominant (more common)
Ocular features	Congenital cataracts (congenital nuclear or pulverulent) Microphthalmia, anophthalmia, coloboma (MAC) spectrum Microcornea Nystagmus
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 diagnosis	Next generation sequencing Targeted gene panels (cataract) Whole exome sequencing Whole genome sequencing
Management	Ocular Management of congenital cataract Management of MAC
Therapies under research	None at present
Further information	OMIM

Jump to top

Additional information

Most congenital cataract cases due to pathogenic mutations in CRYBB1 gene are autosomal dominant in nature. The only autosomal recessive cases were reported by Cohen et al in affected family members of two unrelated consanguineous Bedouin families homozygous for a 1-base pair deletion in exon 2 of CRYBB1 (168delG).^[1]

Jump to top

References

Cohen D, Bar-Yosef U, Levy J, et al. Homozygous CRYBB1 deletion mutation underlies autosomal recessive congenital cataract. Invest Ophthalmol Vis Sci. 2007;48(5):2208‐2213
Mackay DS, Boskovska OB, Knopf HL, Lampi KJ, Shiels A. A nonsense mutation in CRYBB1 associated with autosomal dominant cataract linked to human chromosome 22q. Am J Hum Genet. 2002;71(5):1216‐1221
Wang KJ, Wang S, Cao NQ, Yan YB, Zhu SQ. A novel mutation in CRYBB1 associated with congenital cataract-microcornea syndrome: the p.Ser129Arg mutation destabilizes the βB1/βA3-crystallin heteromer but not the βB1-crystallin homomer. Hum Mutat. 2011;32(3):E2050‐E2060
Willoughby CE, Shafiq A, Ferrini W, et al. CRYBB1 mutation associated with congenital cataract and microcornea. Mol Vis. 2005;11:587‐593

Jump to top

Updated on November 30, 2020

Was this article helpful?

Yes No