CRYBA4 gene

Overview

Gene (OMIM No.)	CRYBA4 (#123631)
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)
Inheritance	Autosomal dominant
Ocular features	Congenital cataracts (nuclear or lamellar) Microcornea (heterozygous p.Gly64Trp mutation) Microphthalmia (heterozygous p.Leu69Pro mutation)
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

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
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
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
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
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

Updated on November 30, 2020