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Yuan X, Dang Q, Li XL. Functional analysis of two mutation sites in the OCA2 gene. Sci Rep 2024; 14:14789. [PMID: 38926510 PMCID: PMC11208167 DOI: 10.1038/s41598-024-64782-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
To analyse the genetic aetiology of a child with oculocutaneous albinism and to explore the effects of two mutation sites on the function of the OCA2 protein at the mRNA and protein levels via the use of recombinant carriers in vitro. Whole-exome sequencing (WES) and Sanger sequencing were used to analyse the pathogenic genes of the child and validate the mutations in the parents. pEGFP and phage vectors carrying wild-type and mutant OCA2 were constructed using the coding DNA sequence (CDS) of the whole gene-synthesized OCA2 as a template and transfected into HEK293T cells, after which expression analysis was performed. The child in this study was born with white skin, hair, eyelashes, and eyebrows and exhibited nystagmus. Genetic analysis indicated that the child carried two heterozygous mutations: c.1079C > T (p.Ser360Phe) of maternal origin and c.1095_1103delAGCACTGGC (p.Ala366_Ala368del) of paternal origin, conforming to an autosomal recessive inheritance pattern. In vitro analysis showed that the expression of the c.1079C > T (p.Ser360Phe) mutant did not significantly change at the mRNA level but did increase at the protein level, suggesting that the mutation may lead to enhanced protein stability, and the c.1095_1103delAGCACTGGC (p.Ala366_Ala368del) mutation resulted in the loss of three amino acids in exon 10, producing a truncated protein. In vitro expression analysis also revealed that the expression of the mutant gene was significantly downregulated at both the mRNA and protein levels, suggesting that the mutation can simultaneously produce truncated proteins and lead to protein degradation. This case study enriches the phenotypic spectrum of OCA2 gene disease. In vitro expression analysis confirmed that both mutations affect protein expression, providing a theoretical basis for analysing the pathogenicity of these two mutations.
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Affiliation(s)
- XiaoHua Yuan
- Department of Gynaecology and Obstetrics, The First Affiliated Hospital of Xi'an Jiaotong University, No. 277, Yanta West Road, Xi'an, 710061, China.
| | - Qun Dang
- Department of Gynaecology and Obstetrics, Shaanxi Provincial People's Hospital, Xi'an, 710068, China
| | - Xue Lan Li
- Department of Gynaecology and Obstetrics, The First Affiliated Hospital of Xi'an Jiaotong University, No. 277, Yanta West Road, Xi'an, 710061, China.
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2
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Muromachi K, Hosomichi K, Park H, Yamaguchi T, Tani-Ishii N. Identification of Candidate Genes of Familial Multiple Idiopathic Cervical Root Resorption. J Endod 2023; 49:1537-1547. [PMID: 37742719 DOI: 10.1016/j.joen.2023.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 09/12/2023] [Accepted: 09/17/2023] [Indexed: 09/26/2023]
Abstract
INTRODUCTION Multiple idiopathic cervical root resorption (MICRR) is a disease with an unknown etiology that causes invasive cervical root resorption in multiple teeth. Although previous MICRR genomic studies have identified candidate gene variants, the etiology of the condition remains poorly understood. In the present study, we investigated the genetic causality of MICRR to explore candidate variants. METHODS Saliva samples from a family containing 2 affected and two unaffected subjects with the dominant transmission of MICRR were subjected to whole-exome sequencing. RESULTS As a result, we identified novel candidate variants of 10 genes. Each variant was confirmed by Sanger sequencing. Among them, the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines classified doublecortin domain containing 1 (c.1099 C > T) and β-defensin 114 (c.189 T > G) as "pathogenic," and solute carrier family 45 member 2 (c.152_153del) as "likely pathogenic." CONCLUSIONS These results provide new insight to help clarify the pathogenesis of MICRR, and the variants could be applied for further investigation to understand invasive cervical root resorption.
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Affiliation(s)
- Koichiro Muromachi
- Department of Endodontics, Graduate School of Dentistry, Kanagawa Dental University, Yokosuka, Kanagawa, Japan.
| | - Kazuyoshi Hosomichi
- Laboratory of Computational Genomics, School of Life Science, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Heetae Park
- Department of Orthodontics, Graduate School of Dentistry, Kanagawa Dental University, Yokosuka, Kanagawa, Japan
| | - Tetsutaro Yamaguchi
- Department of Orthodontics, Graduate School of Dentistry, Kanagawa Dental University, Yokosuka, Kanagawa, Japan.
| | - Nobuyuki Tani-Ishii
- Department of Endodontics, Graduate School of Dentistry, Kanagawa Dental University, Yokosuka, Kanagawa, Japan
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Oculo-Cutaneous Albinism Type 4 (OCA4): Phenotype-Genotype Correlation. Genes (Basel) 2022; 13:genes13122198. [PMID: 36553465 PMCID: PMC9777904 DOI: 10.3390/genes13122198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/04/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022] Open
Abstract
Albinism is a genetic disorder, present worldwide, caused by mutations in genes affecting melanin production or transport in the skin, hair and eyes. To date, mutations in at least 20 different genes have been identified. Oculo-cutaneous Albinism type IV (OCA4) is the most frequent form in Asia but has been reported in all populations, including Europeans. Little is known about the genotype-phenotype correlation. We identified two main phenotypes via the analysis of 30 OCA4 patients with a molecularly proven diagnosis. The first, found in 20 patients, is clinically indistinguishable from the classical OCA1 phenotype. The genotype-to-phenotype correlation suggests that this phenotype is associated with homozygous or compound heterozygous nonsense or deletion variants with frameshift leading to translation interruption in the SLC45A2 gene. The second phenotype, found in 10 patients, is characterized by very mild hypopigmentation of the hair (light brown or even dark hair) and skin that is similar to the general population. In this group, visual acuity is variable, but it can be subnormal, foveal hypoplasia can be low grade or even normal, and nystagmus may be lacking. These mild to moderate phenotypes are associated with at least one missense mutation in SLC45A2.
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Thuong MTH, Anh LTL, Nhung VP, Ngoc TTB, Lan HT, Phuong DK, Ha NH, Van Hai N, Ton ND. Genetic analyses of Vietnamese patients with oculocutaneous albinism. J Clin Lab Anal 2022; 36:e24625. [PMID: 35870188 PMCID: PMC9459276 DOI: 10.1002/jcla.24625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/07/2022] Open
Affiliation(s)
- Ma Thi Huyen Thuong
- Institute of Genome Research (IGR) Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
- Graduated University of Science and Technology Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
| | - Luong Thi Lan Anh
- Department of Medical Biology and Genetics Hanoi Medical University Hanoi Viet Nam
| | - Vu Phuong Nhung
- Institute of Genome Research (IGR) Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
| | - Tran Thi Bich Ngoc
- Institute of Genome Research (IGR) Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
| | - Hoang Thu Lan
- Department of Medical Biology and Genetics Hanoi Medical University Hanoi Viet Nam
| | - Doan Kim Phuong
- Department of Medical Biology and Genetics Hanoi Medical University Hanoi Viet Nam
| | - Nguyen Hai Ha
- Institute of Genome Research (IGR) Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
- Graduated University of Science and Technology Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
| | - Nong Van Hai
- Institute of Genome Research (IGR) Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
- Graduated University of Science and Technology Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
| | - Nguyen Dang Ton
- Institute of Genome Research (IGR) Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
- Graduated University of Science and Technology Vietnam Academy of Science and Technology (VAST) Ha Noi Vietnam
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5
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Expanding the Spectrum of Oculocutaneous Albinism: Does Isolated Foveal Hypoplasia Really Exist? Int J Mol Sci 2022; 23:ijms23147825. [PMID: 35887175 PMCID: PMC9317384 DOI: 10.3390/ijms23147825] [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: 05/14/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 02/05/2023] Open
Abstract
Oculocutaneous albinism is an autosomal recessive disorder characterized by the presence of typical ocular features, such as foveal hypoplasia, iris translucency, hypopigmented fundus oculi and reduced pigmentation of skin and hair. Albino patients can show significant clinical variability; some individuals can present with only mild depigmentation and subtle ocular changes. Here, we provide a retrospective review of the standardized clinical charts of patients firstly addressed for evaluation of foveal hypoplasia and slightly subnormal visual acuity, whose diagnosis of albinism was achieved only after extensive phenotypic and genotypic characterization. Our report corroborates the pathogenicity of the two common TYR polymorphisms p.(Arg402Gln) and p.(Ser192Tyr) when both are located in trans with a pathogenic TYR variant and aims to expand the phenotypic spectrum of albinism in order to increase the detection rate of the albino phenotype. Our data also suggest that isolated foveal hypoplasia should be considered a clinical sign instead of a definitive diagnosis of an isolated clinical entity, and we recommend deep phenotypic and molecular characterization in such patients to achieve a proper diagnosis.
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Zhong Z, Zhou Z, Chen J, Zhang J. Identification of 12 OCA Cases in Chinese Population and Two Novel Variants. Front Genet 2022; 13:926511. [PMID: 35923705 PMCID: PMC9340472 DOI: 10.3389/fgene.2022.926511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/09/2022] [Indexed: 11/21/2022] Open
Abstract
OCA (oculocutaneous albinism) refers to a group of heterogeneous congenital disorders of which the common manifestations are variable degrees of cutaneous hypopigmentation and significant visual impairment, including poor visual acuity, photophobia, and nystagmus. Molecular analysis may elucidate its pathogenesis and be in favor of accurate diagnosis. High-throughput sequencing and Sanger sequencing were performed to detect mutational alleles and in silico analysis was performed for prediction of variant pathogenicity. Ten TYR-related and two OCA2-related patients were identified with 16 different variants with potential pathogenicity. Two novel missense variants [TYR: c.623T > G, p(Leu208Arg) and OCA2: c.1325A > G, p(Asn442Ser)] are identified in this study, and three OCA cases are reported for the first time in Chinese population based on their associated variants. Analysis of crystal structures of TYR ortholog and its paralog TYRP1 suggests that the substitution of Leu208 may have an impact on protein stability. This study may facilitate OCA diagnosis by expanding the mutational spectrum of TYR and OCA2 as well as further basic studies about these two genes.
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Affiliation(s)
- Zilin Zhong
- Birth Defect Group, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Regenerative Medicine, School of Medicine, Tongji University, Shanghai, China
| | - Zheng Zhou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jianjun Chen
- Birth Defect Group, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People’s Hospital, School of Medicine, Tongji University, Shanghai, China
- Department of Medical Genetics, School of Medicine, Tongji University, Shanghai, China
- *Correspondence: Jianjun Chen, Jun Zhang,
| | - Jun Zhang
- Research Center for Translational Medicine, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Stem Cell Translational Research Center of Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- *Correspondence: Jianjun Chen, Jun Zhang,
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Ullah MI. Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review. Genes (Basel) 2022; 13:genes13061072. [PMID: 35741834 PMCID: PMC9222488 DOI: 10.3390/genes13061072] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 02/01/2023] Open
Abstract
Oculocutaneous albinism (OCA) is an autosomal recessive syndromic and non-syndromic defect with deficient or a complete lack of the melanin pigment. The characteristics of OCA appears in skin, hair, and eyes with variable degree of pigmentation. Clinical manifestations of OCA include nystagmus, photophobia, reduced visual acuity, hypo-plastic macula, and iris trans-illumination. There are eight OCA types (OCA1–8) documented with non-syndromic characteristics. Molecular studies identified seven genes linked to the OCA phenotype (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, C10orf11, and DCT) and one locus (OCA5) in consanguineous and sporadic albinism. The complications of OCA result in skin cancer and variable syndromes such as Hermansky–Pudlak syndrome (HPS) Chediak–Higashi syndrome (CHS). In the Pakistani population, autosomal recessive non-syndromic OCA is common and is associated with a large number of consanguineous families, and mutations in genes of non-syndromic types are reported. This review highlights the updates on the genetic mutation of OCA genes reported from Pakistani families. Several studies reported the genetic mutations in OCA1, OCA2, OCA3, OCA4, and OCA6 albinism in Pakistani families. A locus, OCA5, was also reported from the Pakistani population, but the gene has not been identified. A new type of OCA8 was identified due to the DCT gene mutation, and it is also reviewed here.
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Affiliation(s)
- Muhammad Ikram Ullah
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 75471, Aljouf, Saudi Arabia
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8
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Ma L, Zhu J, Wang J, Huang Y, Zhang J, Wang C, Zhou Y, Peng D. Genetic Analysis of 28 Chinese Families With Tyrosinase-Positive Oculocutaneous Albinism. Front Genet 2021; 12:715437. [PMID: 34707637 PMCID: PMC8544823 DOI: 10.3389/fgene.2021.715437] [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: 05/28/2021] [Accepted: 07/30/2021] [Indexed: 11/28/2022] Open
Abstract
Background Tyrosinase-positive oculocutaneous albinism (OCA, type II, OCA2) is an autosomal recessive genetic disease in which the biosynthesis of melanin decreases in the skin, hair, and eyes. OCA2 disease is caused by mutations in OCA2 gene. The gene product plays a role in regulating the pH of melanosomes. Up to now, hundreds of OCA2 mutations have been reported and novel variants are still being discovered. Methods In this study, we reviewed the records of OCA2 patients who had conducted albinism genetic testing, and then analyzed the clinical and genetic information of 28 OCA2 patients who had been genetically diagnosed by using Sanger sequencing and next-generation sequencing. Results In this study, we reported 31 variants screened from 28 Chinese OCA2 families, and characterized the detailed molecular and clinical presentations. There were 12 novel variants among all detected variants, including 3 missense variants (p.G393V, p.T482A, and p.R720P), 4 frameshift variants (p.R53Gfs∗49, p.N279Kfs∗17, p.I469Lfs∗4, p.I655Nfs∗12), 2 splicing variants (c.1637-2A > G, c.1951 + 1G > C), 2 stopgain variants (p.L278X, p.W652X) and 1 insertion variants (p.P315LinsT). One potential cluster of missense variants was implicated indicating the important roles of the underlying domains in OCA2 pathogenesis. Conclusion Our results were beneficial for diagnosis and precision clinical management for OCA2-related disorder, and this study expanded the mutation spectrum of oculocutaneous albinism.
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Affiliation(s)
- Linya Ma
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jianjian Zhu
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jing Wang
- Changsha Kingmed Center for Clinical Laboratory, Changsha, China
| | - Yazhou Huang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jibo Zhang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Chao Wang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Yuan Zhou
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Dan Peng
- Department of Medical Genetics, Changde First People's Hospital, Changde, China.,Affiliated Hospital of Changde City, University of South China, Hengyang, China
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9
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Aamir A, Kuht HJ, Grønskov K, Brooks BP, Thomas MG. Clinical utility gene card for oculocutaneous (OCA) and ocular albinism (OA)-an update. Eur J Hum Genet 2021; 29:1577-1583. [PMID: 33504991 PMCID: PMC8484472 DOI: 10.1038/s41431-021-00809-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/12/2020] [Accepted: 01/08/2021] [Indexed: 02/07/2023] Open
Affiliation(s)
- Abdullah Aamir
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - Helen J Kuht
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - Karen Grønskov
- Rigshospitalet, Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Glostrup, Denmark
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Bethesda, MD, USA
| | - Mervyn G Thomas
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK.
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10
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Dumitrescu AV, Tran J, Pfeifer W, Bhattarai SV, Kemerley A, Dunn TV, Wang K, Scheetz TE, Drack A. Clinical albinism score, presence of nystagmus and optic nerves defects are correlated with visual outcome in patients with oculocutaneous albinism. Ophthalmic Genet 2021; 42:539-552. [PMID: 34251969 DOI: 10.1080/13816810.2021.1933544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Purpose: To correlate clinical features, molecular genetic findings, and visual acuity in a cohort of patients clinically diagnosed with oculocutaneous albinism.Design: Retrospective chart reviewMethods: 58 charts met the inclusion criteria. Clinical examination, ancillary testing, and molecular genetic diagnoses were extracted. A novel clinical albinism score (CAS) was developed.Results: A least one likely pathogenic mutation was found in 44/58 (75.9%) patients. Mutations in the OCA1 gene were the most common (52.3%), followed by OCA2 (34%), OCA4 (2.3%), OA1 (6.8%), and HPS (4.5%). Thirty-four percentage of patients had a complete genotype, 41% had one mutation found and 24% had negative genetic testing. CAS was statistically significantly higher in patients with complete genotype, versus patients with one or no mutations found (p < .01). Better visual acuity was associated with lower CAS and fewer disease-causing mutations (p < .01). Foveal defects and iris transillumination were associated with a higher number of mutations (p < .01). Patients with nystagmus or anomalous optic nerves had worse visual acuity than those who did not (p < .01, p < .05).Conclusions: Patients with a complete genotype were more likely to have higher CAS. Vision loss correlated with complete phenotype and higher CAS, the presence of nystagmus and anomalous optic nerves. Patients with features of albinism in whom an incomplete genotype was found had better vision than those with complete genotype, suggesting a mild occult mutation or modifier variant. Genetic diagnosis is vital for complete diagnosis, counseling, and family planning.
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Affiliation(s)
- Alina V Dumitrescu
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA.,Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Johnny Tran
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Wanda Pfeifer
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Sajag V Bhattarai
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Andrew Kemerley
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Taylor V Dunn
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Kai Wang
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Tod E Scheetz
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Arlene Drack
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
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11
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Loftus SK, Lundh L, Watkins-Chow DE, Baxter LL, Pairo-Castineira E, Nisc Comparative Sequencing Program, Jackson IJ, Oetting WS, Pavan WJ, Adams DR. A custom capture sequence approach for oculocutaneous albinism identifies structural variant alleles at the OCA2 locus. Hum Mutat 2021; 42:1239-1253. [PMID: 34246199 DOI: 10.1002/humu.24257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/02/2021] [Accepted: 06/24/2021] [Indexed: 11/09/2022]
Abstract
Oculocutaneous albinism (OCA) is a heritable disorder of pigment production that manifests as hypopigmentation and altered eye development. Exon sequencing of known OCA genes is unsuccessful in producing a complete molecular diagnosis for a significant number of affected individuals. We sequenced the DNA of individuals with OCA using short-read custom capture sequencing that targeted coding, intronic, and noncoding regulatory regions of known OCA genes, and genome-wide association study-associated pigmentation loci. We identified an OCA2 complex structural variant (CxSV), defined by a 143 kb inverted segment reintroduced in intron 1, upstream of the native location. The corresponding CxSV junctions were observed in 11/390 probands screened. The 143 kb CxSV presents in one family as a copy number variant duplication for the 143 kb region. In the remaining 10/11 families, the 143 kb CxSV acquired an additional 184 kb deletion across the same region, restoring exons 3-19 of OCA2 to a copy-number neutral state. Allele-associated haplotype analysis found rare SNVs rs374519281 and rs139696407 are linked with the 143 kb CxSV in both OCA2 alleles. For individuals in which customary molecular evaluation does not reveal a biallelic OCA diagnosis, we recommend preliminary screening for these haplotype-associated rare variants, followed by junction-specific validation for the OCA2 143 kb CxSV.
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Affiliation(s)
- Stacie K Loftus
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Linnea Lundh
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Dawn E Watkins-Chow
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Laura L Baxter
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Erola Pairo-Castineira
- Roslin Institute, University of Edinburgh, Easter Bush, Edinburgh, UK.,MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | | | - Ian J Jackson
- Roslin Institute, University of Edinburgh, Easter Bush, Edinburgh, UK.,MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, UK
| | - William S Oetting
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
| | - William J Pavan
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - David R Adams
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
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12
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Schidlowski L, Liebert F, Iankilevich PG, Rebellato PRO, Rocha RA, Almeida NAP, Jain A, Wu Y, Itan Y, Rosati R, Prando C. Non-syndromic Oculocutaneous Albinism: Novel Genetic Variants and Clinical Follow Up of a Brazilian Pediatric Cohort. Front Genet 2020; 11:397. [PMID: 32411182 PMCID: PMC7198815 DOI: 10.3389/fgene.2020.00397] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a genetic disorder characterized by skin, hair, and eye hypopigmentation due to a reduction or absence of melanin. Clinical manifestations include vision problems and a high susceptibility to skin cancer. In its non-syndromic form, OCA is associated with six genes and one chromosomal region. Because OCA subtypes are not always clinically distinguishable, molecular analysis has become an important tool for classifying types of OCA, which facilitates genetic counseling and can guide the development of new therapies. We studied eight Brazilian individuals aged 1.5–18 years old with clinical diagnosis of OCA. Assessment of ophthalmologic characteristics showed results consistent with albinism, including reduced visual acuity, nystagmus, and loss of stereoscopic vision. We also observed the appearance of the strabismus and changes in static refraction over a 2-year period. Dermatologic evaluation showed that no participants had preneoplastic skin lesions, despite half of the participants reporting insufficient knowledge about skin care in albinism. Whole-exome and Sanger sequencing revealed eight different mutations: six in the TYR gene and two in the SLC45A2 gene, of which one was novel and two were described in a population study but were not previously associated with the OCA phenotype. We performed two ophthalmological evaluations, 2 years apart; and one dermatological evaluation. To the best of our knowledge, this is the first study to perform clinical follow-up and genetic analysis of a Brazilian cohort with albinism. Here, we report three new OCA causing mutations.
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Affiliation(s)
- Laire Schidlowski
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | - Fernando Liebert
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | | | | | | | | | - Aayushee Jain
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Yiming Wu
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Yuval Itan
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Roberto Rosati
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | - Carolina Prando
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil.,Hospital Pequeno Príncipe, Curitiba, Brazil
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13
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Wu KC, Lv JN, Yang H, Yang FM, Lin R, Lin Q, Shen RJ, Wang JB, Duan WH, Hu M, Zhang J, He ZL, Jin ZB. Nonhuman Primate Model of Oculocutaneous Albinism with TYR and OCA2 Mutations. RESEARCH 2020; 2020:1658678. [PMID: 32259106 PMCID: PMC7086374 DOI: 10.34133/2020/1658678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/04/2020] [Indexed: 12/27/2022]
Abstract
Human visual acuity is anatomically determined by the retinal fovea. The ontogenetic development of the fovea can be seriously hindered by oculocutaneous albinism (OCA), which is characterized by a disorder of melanin synthesis. Although people of all ethnic backgrounds can be affected, no efficient treatments for OCA have been developed thus far, due partly to the lack of effective animal models. Rhesus macaques are genetically homologous to humans and, most importantly, exhibit structures of the macula and fovea that are similar to those of humans; thus, rhesus macaques present special advantages in the modeling and study of human macular and foveal diseases. In this study, we identified rhesus macaque models with clinical characteristics consistent with those of OCA patients according to observations of ocular behavior, fundus examination, and optical coherence tomography. Genomic sequencing revealed a biallelic p.L312I mutation in TYR and a homozygous p.S788L mutation in OCA2, both of which were further confirmed to affect melanin biosynthesis via in vitro assays. These rhesus macaque models of OCA will be useful animal resources for studying foveal development and for preclinical trials of new therapies for OCA.
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Affiliation(s)
- Kun-Chao Wu
- Division of Ophthalmic Genetics, The Eye Hospital, Laboratory for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Wenzhou Medical University, Wenzhou 325027, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China
| | - Ji-Neng Lv
- Division of Ophthalmic Genetics, The Eye Hospital, Laboratory for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Wenzhou Medical University, Wenzhou 325027, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China
| | - Hui Yang
- Division of Ophthalmic Genetics, The Eye Hospital, Laboratory for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Wenzhou Medical University, Wenzhou 325027, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China
| | - Feng-Mei Yang
- Institute of Medical Biology, Chinese Academy of Medical Sciences, And Peking Union Medical College (CAMS & PUMC), Yunnan Key Laboratory of Vaccine Research Development on Severe Infectious Disease, Kunming 650118, China
| | - Rui Lin
- Division of Ophthalmic Genetics, The Eye Hospital, Laboratory for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Wenzhou Medical University, Wenzhou 325027, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China
| | - Qiang Lin
- Division of Ophthalmic Genetics, The Eye Hospital, Laboratory for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Wenzhou Medical University, Wenzhou 325027, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China
| | - Ren-Juan Shen
- Division of Ophthalmic Genetics, The Eye Hospital, Laboratory for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Wenzhou Medical University, Wenzhou 325027, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China
| | - Jun-Bin Wang
- Institute of Medical Biology, Chinese Academy of Medical Sciences, And Peking Union Medical College (CAMS & PUMC), Yunnan Key Laboratory of Vaccine Research Development on Severe Infectious Disease, Kunming 650118, China
| | - Wen-Hua Duan
- Department of Ophthalmology, The Second People's Hospital of Yunnan Province, Fourth Affiliated Hospital of Kunming Medical University, Key Laboratory of Yunnan Province for the Prevention and Treatment of Ophthalmology, Kunming 650021, China
| | - Min Hu
- Department of Ophthalmology, The Second People's Hospital of Yunnan Province, Fourth Affiliated Hospital of Kunming Medical University, Key Laboratory of Yunnan Province for the Prevention and Treatment of Ophthalmology, Kunming 650021, China
| | - Jun Zhang
- National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China.,Laboratory of Retinal Physiology & Disease, The Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China
| | - Zhan-Long He
- Institute of Medical Biology, Chinese Academy of Medical Sciences, And Peking Union Medical College (CAMS & PUMC), Yunnan Key Laboratory of Vaccine Research Development on Severe Infectious Disease, Kunming 650118, China
| | - Zi-Bing Jin
- Division of Ophthalmic Genetics, The Eye Hospital, Laboratory for Stem Cell & Retinal Regeneration, Institute of Stem Cell Research, Wenzhou Medical University, Wenzhou 325027, China.,National Center for International Research in Regenerative Medicine and Neurogenetics, National Clinical Research Center for Ocular Diseases, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou 325027, China
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14
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Wang H, Wan Y, Yang Y, Li H, Mao L, Gao S, Xu J, Wang J. Novel compound heterozygous mutations in OCA2 gene associated with non-syndromic oculocutaneous albinism in a Chinese Han patient: a case report. BMC MEDICAL GENETICS 2019; 20:130. [PMID: 31345173 PMCID: PMC6659248 DOI: 10.1186/s12881-019-0850-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/19/2019] [Indexed: 11/24/2022]
Abstract
Background Oculocutaneous albinism (OCA) is a group of rare genetically heterogeneous disorders. The present study aimed to identify the genetic cause of a Chinese Han family with non-syndromic oculocutaneous albinism (OCA). Case presentation Here, we report an 11-month-old male proband from a Chinese Han non-consanguineous family, who presented with milky skin, yellow white hair, nystagmus, astigmatism, and hypermetropia. We performed the targeted next-generation sequencing (NGS) on the proband and identified two novel compound heterozygous variants (c.1865 T > C (p.Leu622Pro) and exons 17–21 deletion) in OCA2 gene associated with OCA type 2 (OCA2, OMIM 203200). Meanwhile, a previously reported heterozygous mutation (c.4805G > A) in MYO7 gene related with Usher syndrome type 1B was found. The online tools SIFT, PolyPhen-2, and Mutation Taster predicted variant c.1865 T > C was probably damaging. The residue p.Leu622 was in a highly conserved region among species by CLUSTALW. Three-dimensional homology model with I-TASSER indicated that p.Leu622Pro variant disturbed the formation of the α-helix, resulting in a random coil structure. The gross deletion (exons 17–21) in OCA2 gene has was not been reported previously. These two novel variants in OCA2 gene were inherited from each parent respectively, after verification by Sanger sequencing and quantitative PCR (qPCR) in the family. Conclusions This study indicates the two novel compound heterozygous mutations in OCA2 gene may be responsible for clinical manifestations of OCA2. It expands the mutation spectrum of OCA2 gene and is helpful to screen for large deletions with targeted NGS protocol in monogenic disease. It also assists the genetic counselling, carrier screening and personalized healthcare of the disease. Electronic supplementary material The online version of this article (10.1186/s12881-019-0850-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hairong Wang
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China
| | - Yang Wan
- Department of Obstetrics and Gynecology, Fuyang People's Hospital, Fuyang, 236000, China
| | - Yun Yang
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China.,Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Hao Li
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China
| | - Liangwei Mao
- Anhui Clinical Laboratories, BGI-Anhui, BGI-Shenzhen, Weisan Road, Fuyang, 236000, China.,College of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Shuyang Gao
- BGI Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Jingjing Xu
- Prenatal diagnosis center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of University of Science and Technology of China, Hefei, 230071, China
| | - Jing Wang
- Prenatal diagnosis center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of University of Science and Technology of China, Hefei, 230071, China.
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15
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Zhong Z, Gu L, Zheng X, Ma N, Wu Z, Duan J, Zhang J, Chen J. Comprehensive analysis of spectral distribution of a large cohort of Chinese patients with non-syndromic oculocutaneous albinism facilitates genetic diagnosis. Pigment Cell Melanoma Res 2019; 32:672-686. [PMID: 31077556 PMCID: PMC6852118 DOI: 10.1111/pcmr.12790] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 03/31/2019] [Accepted: 05/05/2019] [Indexed: 12/25/2022]
Abstract
Non-syndromic oculocutaneous albinism (nsOCA) is a group of genetically heterogeneous autosomal recessive disorders with complete lack or decrease pigmentation in skin, hair, and eyes. TYR, OCA2, TYRP1, SLC45A2, SLC24A5, and LRMDA were reported to cause OCA1-4 and OCA6-7, respectively. By sequencing all the known nsOCA genes in 114 unrelated Chinese nsOCA patients combined with In silico analyses, splicing assay, and classification of variants according to the standards and guidelines of American College of Medical Genetics and Genomics, we detected seventy-one different OCA-causing variants separately in TYR, OCA2, SLC45A2, and SLC24A5, including thirty-one novel variants (13 in TYR, 11 in OCA2, and 7 in SLC45A2). This study shows that OCA1 is the most common (75/114) and OCA2 ranks the second most common (16/114) in Chinese. 99 patients of our cohort were caused by variants of all the known nsOCA genes. Cutaneous phenotypes of OCA1, OCA2, and OCA4 patients were shown in this study. The second OCA6 case in China was identified here. These data expand the spectrum of OCA variants as well phenotype and facilitate clinical implement of Chinese OCA patients.
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Affiliation(s)
- Zilin Zhong
- Department of Pediatrics of Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Medical Genetics, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China
| | - Li Gu
- Department of Pediatrics of Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiujie Zheng
- Department of Pediatrics of Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Medical Genetics, Tongji University School of Medicine, Shanghai, China
| | - Nengjun Ma
- Department of Pediatrics of Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Medical Genetics, Tongji University School of Medicine, Shanghai, China
| | - Zehua Wu
- Department of Pediatrics of Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Medical Genetics, Tongji University School of Medicine, Shanghai, China
| | - Juan Duan
- Department of Auxiliary Reproductive, Jiujiang Maternal and Child Health Hospital, Jiujiang, China
| | - Jun Zhang
- Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China
| | - Jianjun Chen
- Department of Pediatrics of Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Medical Genetics, Tongji University School of Medicine, Shanghai, China.,Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai, China
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