CRYBA2 gene

Overview

Gene (OMIM No.)	CRYBA2 (#600836)
Function of gene/protein	Protein: crystallin beta A2 Lens-specific protein with both structural and functional components Involved in lens development Highly soluble and transparent structure helps to maintain lens transparency Functions as a molecular chaperone in its oxidised form Binds to misfolded proteins to prevent aggregation
Clinical phenotype (OMIM phenotype no.)	Cataract 42 (#115900)
Inheritance	Autosomal dominant
Ocular features	Incomplete penetrance Congenital cataracts most common but 2 patients were diagnosed later (aged 9 and 38 years) Variable morphology: multifocal congenital cataract, juvenile or posterior polar cataract Eccentric pupil Myopia Glaucoma
Systemic features	No extraocular features have been reported
Key investigations	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
Therapies under research	None at present
Further information	OMIM

Hulsebos TJ, Cerosaletti KM, Fournier RE, et al. Identification of the human beta A2 crystallin gene (CRYBA2): localization of the gene on human chromosome 2 and of the homologous gene on mouse chromosome 1. Genomics. 1995;28(3):543‐548
Lapko VN, Smith DL, Smith JB. Expression of betaA2-crystallin in human lenses. Exp Eye Res. 2003;77(3):383‐385
Puk O, Ahmad N, Wagner S, Hrabé de Angelis M, Graw J. First mutation in the βA2-crystallin encoding gene is associated with small lenses and age-related cataracts. Invest Ophthalmol Vis Sci. 2011;52(5):2571‐2576. Published 2011 Apr 20
Reis LM, Tyler RC, Muheisen S, et al. Whole exome sequencing in dominant cataract identifies a new causative factor, CRYBA2, and a variety of novel alleles in known genes. Hum Genet. 2013;132(7):761‐770

Updated on November 30, 2020

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