GJA3 gene

Overview
Congenital cataract
Microphthalmia, anophthalmia, coloboma (MAC)
References

Overview

Gene (OMIM No.)	GJA3 (#121015)
Function of gene/protein	Protein: gap junction alpha 3 protein/ connexin 46 Structural component of lens fibre gap junctions Formation of channels through which neighboring cells can communicate and allow small molecules and ions to diffuse between cells Maintaining lens transparency and its optical properties by regulating ionic and water balance in lens cells
Clinical phenotype (OMIM phenotype no.)	Cataract 14, multiple types (#601885)
Inheritance	Autosomal dominant
Ocular features	Congenital cataract (nuclear pulverulent, zonular pulverulent, posterior polar, nuclear coralliform, embryonal nuclear or Coppock-like) Microcornea Microphthalmia, anophthalmia, coloboma (MAC) spectrum
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 Assessment with a pediatrician 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

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References

Burdon KP, Wirth MG, Mackey DA, et al. A novel mutation in the Connexin 46 gene causes autosomal dominant congenital cataract with incomplete penetrance [published correction appears in J Med Genet. 2005 Mar;42(3):288] [published correction appears in J Med Genet. 2008 Apr;45(4):256]. J Med Genet. 2004;41(8):e106
Chang B, Wang X, Hawes NL, et al. A Gja8 (Cx50) point mutation causes an alteration of alpha 3 connexin (Cx46) in semi-dominant cataracts of Lop10 mice. Hum Mol Genet. 2002;11(5):507‐513
Li Y, Wang J, Dong B, Man H. A novel connexin46 (GJA3) mutation in autosomal dominant congenital nuclear pulverulent cataract. Mol Vis. 2004;10:668‐671
Mackay D, Ionides A, Kibar Z, et al. Connexin46 mutations in autosomal dominant congenital cataract. Am J Hum Genet. 1999;64(5):1357‐1364
Minogue PJ, Liu X, Ebihara L, Beyer EC, Berthoud VM. An aberrant sequence in a connexin46 mutant underlies congenital cataracts. J Biol Chem. 2005;280(49):40788‐40795
Rees MI, Watts P, Fenton I, et al. Further evidence of autosomal dominant congenital zonular pulverulent cataracts linked to 13q11 (CZP3) and a novel mutation in connexin 46 (GJA3). Hum Genet. 2000;106(2):206‐209
White TW. Unique and redundant connexin contributions to lens development. Science. 2002;295(5553):319‐320
Zhang L, Qu X, Su S, Guan L, Liu P. A novel mutation in GJA3 associated with congenital Coppock-like cataract in a large Chinese family. Mol Vis. 2012;18:2114‐2118
Zhang X, Wang L, Wang J, Dong B, Li Y. Coralliform cataract caused by a novel connexin46 (GJA3) mutation in a Chinese family. Mol Vis. 2012;18:203‐210

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Updated on November 30, 2020

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