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Owji AP, Kittredge A, Zhang Y, Yang T. Structure and Function of the Bestrophin family of calcium-activated chloride channels. Channels (Austin) 2021; 15:604-623. [PMID: 34612806 PMCID: PMC8496536 DOI: 10.1080/19336950.2021.1981625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Bestrophins are a family of calcium-activated chloride channels (CaCCs) with relevance to human physiology and a myriad of eye diseases termed "bestrophinopathies". Since the identification of bestrophins as CaCCs nearly two decades ago, extensive studies from electrophysiological and structural biology perspectives have sought to define their key channel features including calcium sensing, gating, inactivation, and anion selectivity. The initial X-ray crystallography studies on the prokaryotic homolog of Best1, Klebsiella pneumoniae (KpBest), and the Best1 homolog from Gallus gallus (chicken Best1, cBest1), laid the foundational groundwork for establishing the architecture of Best1. Recent progress utilizing single-particle cryogenic electron microscopy has further elucidated the molecular mechanism of gating in cBest1 and, separately, the structure of Best2 from Bos taurus (bovine Best2, bBest2). Meanwhile, whole-cell patch clamp, planar lipid bilayer, and other electrophysiologic analyses using these models as well as the human Best1 (hBest1) have provided ample evidence describing the functional properties of the bestrophin channels. This review seeks to consolidate these structural and functional results to paint a broad picture of the underlying mechanisms comprising the bestrophin family's structure-function relationship.
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Affiliation(s)
- Aaron P Owji
- Department of Pharmacology, Columbia University, NY, USA
| | - Alec Kittredge
- Department of Pharmacology, Columbia University, NY, USA
| | - Yu Zhang
- Department of Ophthalmology, Columbia University, NY, USA
| | - Tingting Yang
- Department of Ophthalmology, Columbia University, NY, USA
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Lin Y, Li T, Liu B, Lyu C, Lian Y, Li J, Huang Y, Li H, Wu Q, Jin C, Lu L. Multimodal imaging and genetic analysis of adult-onset best vitelliform macular dystrophy in Chinese patients. Exp Ther Med 2021; 22:1034. [PMID: 34373720 PMCID: PMC8343652 DOI: 10.3892/etm.2021.10466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 06/16/2021] [Indexed: 01/09/2023] Open
Abstract
Compared to juvenile-onset best vitelliform macular dystrophy (BVMD), adult-onset BVMD is not well characterized and lacks strict diagnostic criteria. The present study aimed to evaluate the clinical and genetic characteristics of four advanced-age Chinese patients with adult-onset BVMD by combining multimodal imaging and genetic analysis. The four patients (all older than 50 years) were diagnosed with adult-onset BVMD at Zhongshan Ophthalmic Center (Guangzhou, China). Comprehensive ophthalmic examinations were performed, including analyses of best-corrected visual acuity, intraocular pressure, slit-lamp examination, fundus photography, optical coherence tomography, fundus fluorescein angiography and electrooculography. Genomic DNA was extracted from leukocytes isolated from peripheral blood obtained from these patients, their family members and 200 unrelated subjects from the same population. A total of 11 exons of the bestrophin-1 (BEST1) gene were amplified using PCR and sequenced. All of the four patients presented with lesions in the macular area. The patients were diagnosed with adult-onset BVMD based on multimodal imaging and genetic analysis. A total of four recurrent mutations, namely c.763C>T (p.Arg255Trp, p.R255W) in exon 7, c.584C>T (p.Ala195Val, p.A195V) in exon 5, c.910_912del GAT (p.304delAsp, p.D304del) in exon 8 and c.310G>C (p.Asp104His, p.D104H) in exon 4 of BEST1, were identified. Sorting intolerant from tolerant predicted that the amino acid substitutions p.R255W, p.A195V and p.D104H in the BEST1 protein were causing the damage. Combining multimodal imaging and genetic analysis was helpful in confirming the diagnosis of patients with adult-onset BVMD. These results maybe valuable for clinical and genetic counseling and for the development of therapeutic interventions for patients with BVMD.
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Affiliation(s)
- Ying Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Tao Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Bingqian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Cancan Lyu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China.,Department of Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Yu Lian
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Jizhu Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Ying Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Haichun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Qingxiu Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Chenjin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Lin Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, P.R. China
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Yamada R, Takagi R, Iwamoto S, Shimada S, Kakehashi A. Novel BEST1 mutation in autosomal recessive bestrophinopathy in Japanese siblings. Taiwan J Ophthalmol 2021; 11:71-76. [PMID: 33767958 PMCID: PMC7971447 DOI: 10.4103/tjo.tjo_37_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/18/2020] [Indexed: 11/04/2022] Open
Abstract
PURPOSE Autosomal recessive bestrophinopathy (ARB) is a disease that results from the mutations in the BEST1 gene. It is characterized by multifocal yellowish lipofuscin deposits, cystoid macular edema, and subretinal fluid. Among approximately 270 BEST1 mutations, only 40 that include both heterozygous and homozygous mutations are associated with ARB. However, very few ARB-related mutations have been reported in the Japanese population. Therefore, in this study, we aimed to identify BEST1 mutations and describe the genotype-phenotype relationship in Japanese dizygotic twins presenting with ARB. MATERIALS AND METHODS We performed clinical examinations in Japanese dizygotic twin patients (male: 29 years) with ARB as well as whole-exome sequencing in seven family members of these twins. RESULTS In this study, we have reported on a novel BEST1 mutation, the p. Phe151Cys mutation, associated with ARB in Japanese dizygotic twins who had bi-allelic p. Ala160Pro mutations in BEST1. The clinical features observed were binocular abnormalities of the fundus, such as multifocal yellowish subretinal deposits, cystoid macular edema, and subretinal fluid. The full-field electroretinography results were subnormal. CONCLUSION It was indicated that the novel BEST1 mutations identified may be strongly correlated with binocular ARB. This study provides significant information of the genotype-phenotype association in Japanese ARB patients. Further, the genetic analysis that we performed was very useful for the differential diagnosis and might have implications in the development of future treatment modalities.
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Affiliation(s)
- Rika Yamada
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Department of Ophthalmology, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Rina Takagi
- Department of Ophthalmology, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Sadahiko Iwamoto
- Division of Human Genetics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Shoichi Shimada
- Department of Neuroscience and Cell Biology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Addiction Research Unit, Development of Novel Diagnosis and Treatment Division, Osaka Psychiatric Research Center, Osaka Psychiatric Medical Center,Osaka Prefectural Hospital Organization, Otemae, Chuo-ku, Osaka, Japan
| | - Akihiro Kakehashi
- Department of Ophthalmology, Saitama Medical Center, Jichi Medical University, Saitama, Japan
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Garza-Garza LA, León-Cachón RBR, Aguirre-Garza M, Garza-Leon M. "Novel p.Tyr284Cys BEST1 genotype-phenotype correlations of Vitelliform Macular Dystrophy in a family with incomplete penetrance". Ophthalmic Genet 2020; 41:183-188. [PMID: 32207364 DOI: 10.1080/13816810.2020.1744020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Purpose: Vitelliform Macular Dystrophy is an inherited autosomal dominant disease with variable expressivity, caused by a mutation in the BEST1 gene. We report a family with variable expressivity and incomplete penetrance in its members.Materials and Methods: A Mexican family was studied. It was comprised of six individuals (father, mother, and four children). A clinical history was taken, and a complete ophthalmological examination (distance best-corrected visual acuity, slit-lamp biomicroscopy, optical coherence tomography, fundus autofluorescence, optical coherence tomography angiography, and electrophysiological studies) was performed in each individual.Results: Two members presented low visual acuity and vitelliform lesions in different stages in the ocular fundus. The assessment suggested a diagnosis of Vitelliform Macular Dystrophy. Genetic analysis was performed by sequencing of exons 2, 4, 5, 7, 8, and 9 of the BEST1 gene. All patients were carriers of the A variant allele of SNP rs1109748 located in exon 2 (c.219 C > A; p.Ile73=). Also, a missense mutation was identified in exon 7 in the mother and two children (c.851A>G; p.Tyr284Cys). The mother has a normal visual acuity, no abnormal findings in the ophthalmological examination and an abnormal electrooculogram, exhibiting incomplete penetrance.Conclusion: This represents one of the few cases of Vitelliform Macular Dystrophy with incomplete penetrance, being the first in our country and Latin America, and with our reported mutation with this characteristic.
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Affiliation(s)
| | - Rafael Baltazar Reyes León-Cachón
- Centro de Diagnóstico Molecular y Medicina Personalizada, Departamento de Ciencias Básicas, Escuela de Medicina, Vicerrectoría de Ciencias de la Salud, Universidad de Monterrey, Monterrey, México
| | - Marcelino Aguirre-Garza
- Centro de Diagnóstico Molecular y Medicina Personalizada, Departamento de Ciencias Básicas, Escuela de Medicina, Vicerrectoría de Ciencias de la Salud, Universidad de Monterrey, Monterrey, México
| | - Manuel Garza-Leon
- Departamento de Ciencias Clínicas de la División de Ciencias de la Salud, Universidad de Monterrey, San Pedro Garza García, México
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Lin Y, Gao H, Zhu Y, Chen C, Li T, Liu B, Lyu C, Huang Y, Li H, Wu Q, Jin C, Liang X, Huang X, Lu L. Two Paired Box 6 mutations identified in Chinese patients with classic congenital aniridia and cataract. Mol Med Rep 2018; 18:4439-4445. [PMID: 30221735 PMCID: PMC6172400 DOI: 10.3892/mmr.2018.9469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 08/02/2018] [Indexed: 02/02/2023] Open
Abstract
Congenital aniridia is a rare genetic disorder characterized by a variable degree of hypoplasia or absence of iris. It is frequently associated with keratopathy, cataract, juvenile-onset glaucoma and foveal and optic nerve hypoplasia. Mutations in the Paired Box 6 (PAX6) gene on chromosome 11p13 have been demonstrated to cause aniridia. The aim of the present study was to investigate the genetic variations of PAX6 in two sporadic patients from southern China with classic congenital aniridia and cataract. Complete ophthalmic and physical examinations were performed, including best-corrected visual acuity, intraocular pressure, slit-lamp examination, fundus examination, optical coherence tomography, ultrasound biomicroscopy, and Pentacam scanning. Genomic DNA was extracted from leukocytes of peripheral blood collected from the two patients, their unaffected parents and 200 unrelated control subjects from the same population. Exons 4–13 of the PAX6 gene were amplified by polymerase chain reaction and sequenced directly. Patient 1 was affected with aniridia accompanied by congenital cataract and nystagmus. A novel heterozygous PAX6 frameshift mutation c.277delG (p.Glu93SerfsX31) in exon 6 was identified in this patient. Patient 2 was presented with aniridia, congenital cataract, lens subluxation and glaucoma. A recurrent nonsense mutation c.718C>T (p.Arg240X) in exon 9 was identified in this patient. The present results expand the mutation spectrum of PAX6 and will be valuable for genetic counseling in the affected families. Additionally, the identification of these mutations reiterates the importance of PAX6 in ocular development and sheds light on the pathogenesis of congenital aniridia.
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Affiliation(s)
- Ying Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Hongbin Gao
- Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Yi Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Chuan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Tao Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Bingqian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Cancan Lyu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Ying Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Haichun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Qingxiu Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Chenjin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Xiaoling Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Xinhua Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Lin Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
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Huang X, Lin Y, Chen C, Zhu Y, Gao H, Li T, Liu B, Lyu C, Huang Y, Wu Q, Li H, Jin C, Liang X, Lu L. Targeted next‑generation sequencing identifies two novel COL2A1 gene mutations in Stickler syndrome with bilateral retinal detachment. Int J Mol Med 2018; 42:1819-1826. [PMID: 30015854 PMCID: PMC6108863 DOI: 10.3892/ijmm.2018.3752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/19/2018] [Indexed: 01/12/2023] Open
Abstract
Stickler syndrome is a group of inherited connective tissue disorders characterized by distinctive facial and ocular abnormalities, hearing loss and early‑onset arthritis. The aim of the present study was to investigate the genetic changes in two Chinese patients with Stickler syndrome, manifested as bilateral retinal detachment and peripheral retinal degeneration. Complete ophthalmic examinations, including best‑corrected visual acuity, slit‑lamp examination and fundus examination, were performed. Genomic DNA was extracted from leukocytes of the peripheral blood collected from the patients, their unaffected family members and 200 unrelated control subjects from the same population. Next‑generation sequencing of established genes associated with ocular disease was performed. A heterozygous collagen type II α1 chain (COL2A1) mutation c.1310G>C (p.R437P) in exon 21 was identified in Family 1 and a heterozygous COL2A1 mutation c.2302‑1G>A in intron 34 was identified in Family 2. The functional effects of the mutations were assessed by polymorphism phenotyping (PolyPhen) and sorting intolerant from tolerant (SIFT) analysis. The c.1310G>C mutation was predicted to damage protein structure and function, and the c.2302‑1G>A mutation was predicted to result in a splicing defect. The findings of the current study expand the established mutation spectrum of COL2A1, and may facilitate genetic counseling and development of therapeutic strategies for patients with Stickler syndrome.
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Affiliation(s)
- Xinhua Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Ying Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Chuan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Yi Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Hongbin Gao
- Department of Toxicology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Tao Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Bingqian Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Cancan Lyu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Ying Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Qingxiu Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Haichun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Chenjin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Xiaoling Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Lin Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China
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