A novel Cx50 (GJA8) p.H277Y mutation associated with autosomal dominant congenital cataract identified with targeted next-generation sequencing
- 372 Downloads
To unravel the molecular genetic background responsible for autosomal dominant congenital pulverulent nuclear cataracts in a four-generation Chinese family.
Family history data were collected, ophthalmological examinations were performed, and genomic DNA was extracted from peripheral blood of the family members. The candidate genes were captured and sequenced by targeted next-generation sequencing, and the results were confirmed by Sanger sequencing. The structure modelling of the protein was displayed based on Swiss-Model Server, and its possible changes in the secondary structure were predicted using Antheprot 2000 software. The chemical dissimilarity and possible functional impact of an amino acid substitution were performed with Grantham score, PolyPhen-2, and SIFT predictions. Protein distributions were assessed by confocal microscopy.
A novel heterozygous c.829C > T transition that led to the substitution of a highly conserved histidine by tyrosine at codon 277 (p.H277Y) in the coding region of connexin50 (Cx50, GJA8) was identified. Bioinformatics analysis showed that the mutation likely altered the secondary structure of the protein by replacing the helix of the COOH-terminal portion with a turn. The mutation was predicted to be moderately conservative by Grantham score and to be deleterious by both PolyPhen-2 and SIFT with consistent results. In addition, when expressed in COS1 cells, the mutation led to protein accumulation and caused changes in Cx 50 protein localization pattern.
This is a novel missense mutation [c.829C > T, (p.H277Y)] identified in exon 2 of Cx50. Our findings expand the spectrum of Cx50 mutations that are associated with autosomal dominant congenital pulverulent nuclear cataract.
KeywordsCongenital cataract Connexin GJA8 Missense mutation Next-generation sequencing
We are grateful for all the participating members of the congenital cataract family. We also express our sincere gratitude to Daoyun Zhang, Yunbing Zhang, Chencheng Wang, Zhongqiong Lu, and Qingfu Wang for their technical assistance. This work was supported by grants from the National Science and Technology Pillar Program of the Twelfth Five-year Plan (2011ZX09302-007-02) and the Research Fund for the National Nature Science Funding of China (No. 81273424 and 81170862).
Conflict of interest
All authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest, or non-financial interest in the subject matter or materials discussed in this manuscript.
- 1.Wang KJ, Wang S, Cao NQ, Yan YB, Zhu SQ (2011) 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 32:E2050–E2060CrossRefPubMedCentralPubMedGoogle Scholar
- 10.Arora A, Minogue PJ, Liu X, Reddy MA, Ainsworth JR, Bhattacharya SS, Webster AR, Hunt DM, Ebihara L, Moore AT, Beyer EC, Berthoud VM (2006) A novel GJA8 mutation is associated with autosomal dominant lamellar pulverulent cataract: further evidence for gap junction dysfunction in human cataract. J Med Genet 43:e2CrossRefPubMedCentralPubMedGoogle Scholar
- 18.Zenteno JC, Crespí J, Buentello-Volante B, Buil JA, Bassaganyas F, Vela-Segarra JI, Diaz-Cascajosa J, Marieges MT (2014) Next generation sequencing uncovers a missense mutation in COL4A1 as the cause of familial retinal arteriolar tortuosity. Graefes Arch Clin Exp Ophthalmol 252:1789–1794CrossRefPubMedGoogle Scholar
- 36.Bouvier D, Spagnol G, Chenavas S, Kieken F, Vitrac H, Brownell S, Kellezi A, Forge V, Sorgen PL (2009) Characterization of the structure and intermolecular interactions between the connexin40 and connexin43 carboxyl-terminal and cytoplasmic loop domains. J Biol Chem 284:34257–34271CrossRefPubMedCentralPubMedGoogle Scholar