Tags

Type your tag names separated by a space and hit enter

A novel deep intronic COL2A1 mutation in a family with early-onset high myopia/ocular-only Stickler syndrome.
Ophthalmic Physiol Opt. 2020 05; 40(3):281-288.OP

Abstract

PURPOSE

To identify the genetic defect causing early-onset high myopia (eoHM)/ocular-only Stickler syndrome (ocular-STL) in a large Chinese family.

METHODS

Genomic DNA and clinical data from a four-generation family with eoHM/ocular-STL were collected. Whole-exome sequencing was performed on one affected member in initial screening. Linkage scan based on microsatellite markers was carried out initially from candidate loci associated with autosomal dominant eoHM and Stickler syndrome. Sanger sequencing was used to detect potential variants. The pathogenicity of candidate variants was evaluated using mini genes ex vivo.

RESULTS

Eight patients and five unaffected members in the family participated in the study, in which the patients had high myopia with other variable ocular phenotypes but without extraocular abnormalities. Whole exome sequencing did not detect any potential pathogenic variant in all genes known to associate with the disease. The eoHM/ocular-STL in the family was mapped to markers around COL2A1 by candidate loci linkage scan, with a maximum lod score of 3.31 for D12S1590 at θ = 0. A novel deep intronic variant, c.86-50C > G in intron 1 of COL2A1, was detected by Sanger sequencing and co-segregated with eoHM/ocular-STL in the family. Ex vivo splicing test using mini genes confirmed that the variant created a new splicing acceptor 49 bp before the canonical splicing site of exon 2, resulted in addition of 49 bp fragment in the transcript (from c.86-49 to c.86-1) and premature termination.

CONCLUSIONS

Linkage study, bioinformatics prediction, and ex vivo transcript analysis suggest a novel deep intronic variant adjacent to 5-prime of exon 2 of COL2A1, affecting exon 2 splicing, as a potential cause of ocular-STL in a large family. To our knowledge, this is the first report of an intronic variant around exon 2 as a cause of ocular-STL while a series of variants in the coding region of exon 2, a dispensable alternative-splicing exon for extraocular tissues, in COL2A1 have been reported to cause Stickler syndrome-related ocular phenotype alone.

Authors+Show Affiliations

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

32196734

Citation

Sun, Wenmin, et al. "A Novel Deep Intronic COL2A1 Mutation in a Family With Early-onset High Myopia/ocular-only Stickler Syndrome." Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists), vol. 40, no. 3, 2020, pp. 281-288.
Sun W, Xiao X, Li S, et al. A novel deep intronic COL2A1 mutation in a family with early-onset high myopia/ocular-only Stickler syndrome. Ophthalmic Physiol Opt. 2020;40(3):281-288.
Sun, W., Xiao, X., Li, S., Jia, X., & Zhang, Q. (2020). A novel deep intronic COL2A1 mutation in a family with early-onset high myopia/ocular-only Stickler syndrome. Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists), 40(3), 281-288. https://doi.org/10.1111/opo.12682
Sun W, et al. A Novel Deep Intronic COL2A1 Mutation in a Family With Early-onset High Myopia/ocular-only Stickler Syndrome. Ophthalmic Physiol Opt. 2020;40(3):281-288. PubMed PMID: 32196734.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A novel deep intronic COL2A1 mutation in a family with early-onset high myopia/ocular-only Stickler syndrome. AU - Sun,Wenmin, AU - Xiao,Xueshan, AU - Li,Shiqiang, AU - Jia,Xiaoyun, AU - Zhang,Qingjiong, Y1 - 2020/03/20/ PY - 2019/11/22/received PY - 2020/02/13/accepted PY - 2020/3/21/pubmed PY - 2021/7/22/medline PY - 2020/3/21/entrez KW - COL2A1 KW - deep intronic variant KW - early-onset high myopia KW - family KW - ocular-only Stickler syndrome SP - 281 EP - 288 JF - Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists) JO - Ophthalmic Physiol Opt VL - 40 IS - 3 N2 - PURPOSE: To identify the genetic defect causing early-onset high myopia (eoHM)/ocular-only Stickler syndrome (ocular-STL) in a large Chinese family. METHODS: Genomic DNA and clinical data from a four-generation family with eoHM/ocular-STL were collected. Whole-exome sequencing was performed on one affected member in initial screening. Linkage scan based on microsatellite markers was carried out initially from candidate loci associated with autosomal dominant eoHM and Stickler syndrome. Sanger sequencing was used to detect potential variants. The pathogenicity of candidate variants was evaluated using mini genes ex vivo. RESULTS: Eight patients and five unaffected members in the family participated in the study, in which the patients had high myopia with other variable ocular phenotypes but without extraocular abnormalities. Whole exome sequencing did not detect any potential pathogenic variant in all genes known to associate with the disease. The eoHM/ocular-STL in the family was mapped to markers around COL2A1 by candidate loci linkage scan, with a maximum lod score of 3.31 for D12S1590 at θ = 0. A novel deep intronic variant, c.86-50C > G in intron 1 of COL2A1, was detected by Sanger sequencing and co-segregated with eoHM/ocular-STL in the family. Ex vivo splicing test using mini genes confirmed that the variant created a new splicing acceptor 49 bp before the canonical splicing site of exon 2, resulted in addition of 49 bp fragment in the transcript (from c.86-49 to c.86-1) and premature termination. CONCLUSIONS: Linkage study, bioinformatics prediction, and ex vivo transcript analysis suggest a novel deep intronic variant adjacent to 5-prime of exon 2 of COL2A1, affecting exon 2 splicing, as a potential cause of ocular-STL in a large family. To our knowledge, this is the first report of an intronic variant around exon 2 as a cause of ocular-STL while a series of variants in the coding region of exon 2, a dispensable alternative-splicing exon for extraocular tissues, in COL2A1 have been reported to cause Stickler syndrome-related ocular phenotype alone. SN - 1475-1313 UR - https://www.unboundmedicine.com/medline/citation/32196734/A_novel_deep_intronic_COL2A1_mutation_in_a_family_with_early_onset_high_myopia/ocular_only_Stickler_syndrome_ L2 - https://doi.org/10.1111/opo.12682 DB - PRIME DP - Unbound Medicine ER -