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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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Huo L, Zhang X, Pang Y, Qi Y, Ren S, Wu F, Shang Y, Xi J. Expression and Mutation of SLC45A2 Affects Iris Color in Quail. J Poult Sci 2024; 61:2024015. [PMID: 38818526 PMCID: PMC11130394 DOI: 10.2141/jpsa.2024015] [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: 01/22/2024] [Accepted: 05/09/2024] [Indexed: 06/01/2024] Open
Abstract
Iris color is a prominent phenotypic feature of quail. To understand the mechanism of melanin deposition related to quail iris color, iris tissues were selected from Beijing white and Chinese yellow quail for transcriptome analysis. Differentially expressed genes (DEGs) associated with pigmentation were identified using RNA sequencing and validated by quantitative real-time polymerase chain reaction (RT-qPCR). The identified single nucleotide polymorphisms were studied using bioinformatics and iris color correlation analyses. A total of 485 DEGs were obtained, with 223 upregulated and 262 downregulated. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed. Thirty-two genes were annotated using the GO database. Three important pigment synthesis pathways (Notch signaling, melanogenesis, and tyrosine metabolism) were identified in quail iris tissue (P < 0.05). The expression levels of solute carrier family 45 member 2 (SLC45A2), tyrosinase-related protein 1, vitamin D receptor, opsin 5, and docking protein 5 were significantly different between Beijing white and Chinese yellow quail, as verified by RT-qPCR. The c.1061C>T mutation in SLC45A2, which caused a single amino acid change at position 354 (threonine to methionine), was significantly associated with iris color in Beijing white and Chinese yellow quail, and might be the main reason for the different iris colors between these two quail species.
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Affiliation(s)
- Linke Huo
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
| | - Xiaohui Zhang
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
- Luoyang Key Laboratory of Animal Genetics and Breeding,
Luoyang 471003, P.R. China
| | - Youzhi Pang
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
- Luoyang Key Laboratory of Animal Genetics and Breeding,
Luoyang 471003, P.R. China
| | - Yanxia Qi
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
- Luoyang Key Laboratory of Animal Genetics and Breeding,
Luoyang 471003, P.R. China
| | - Shiwei Ren
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
| | - Fanghu Wu
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
| | - Yuanyuan Shang
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
| | - Jinquan Xi
- College of Animal Science, Henan University of Science and
Technology, Luoyang, 471003 He’nan, P.R. China
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Thuma TBT, Procopio RA, Jimenez HJ, Gunton KB, Pulido JS. Hypomorphic variants in inherited retinal and ocular diseases: A review of the literature with clinical cases. Surv Ophthalmol 2024; 69:337-348. [PMID: 38036193 DOI: 10.1016/j.survophthal.2023.11.006] [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: 06/20/2022] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023]
Abstract
Hypomorphic variants decrease, but do not eliminate, gene function via a reduction in the amount of mRNA or protein product produced by a gene or by production of a gene product with reduced function. Many hypomorphic variants have been implicated in inherited retinal diseases (IRDs) and other genetic ocular conditions; however, there is heterogeneity in the use of the term "hypomorphic" in the scientific literature. We searched for all hypomorphic variants reported to cause IRDs and ocular disorders. We also discuss the presence of hypomorphic variants in the patient population of our ocular genetics department over the past decade. We propose that standardized criteria should be adopted for use of the term "hypomorphic" to describe gene variants to improve genetic counseling and patient care outcomes.
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Affiliation(s)
- Tobin B T Thuma
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | | | - Hiram J Jimenez
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA
| | - Kammi B Gunton
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | - Jose S Pulido
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA; Retina Service, Wills Eye Hospital, Philadelphia, PA, USA.
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Tomás-Velázquez A, Moreno-Artero E, Romero J, Escalonilla P, Medina I, Petiti GH, Redondo P. What Have We Learned about the Prevention of NMSC from Albino Patients from Malawi? Secondary Prevention Maintained over Time. Cancers (Basel) 2024; 16:1522. [PMID: 38672604 PMCID: PMC11048476 DOI: 10.3390/cancers16081522] [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: 03/26/2024] [Revised: 04/12/2024] [Accepted: 04/14/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND We have conducted cooperative campaigns focusing on albino patients in a rural area of Malawi. What have we learned? METHODS Three surgical campaigns were performed in Nkhotakota district (2019-2023). Albino clinical and tumor characteristics were collected. RESULTS Between 22 and 75 albinos were evaluated in each campaign (mean age < 28 years old). Most patients did not use sunscreen in a way that provided optimal photoprotection. Regarding tumors, the proportion of basal and squamous cell carcinomas ranged from 1:1 to almost 2:1. Of 156 albino patients, 34 attended more than once. However, of the 19 patients with 30 tumors operated on in 2021, only seven were assessed the following year (12 were lost to follow-up). At least 14 albinos with locally advanced tumors were evaluated. CONCLUSIONS Distributing photoprotective clothing could be more efficient or perhaps an earlier measure of sunscreen in rural Africa as it does not require permanent repositioning. Very-high-risk patients (previous interventions with positive margins or high-risk tumors, intense actinic damage, and new tumors constantly appearing, especially those presenting SCCs) require close follow-up and treatment and represent our main target. Secondary prevention with Malawian collaboration and the use of teledermatology is essential for patient tracking, as they are able to offer curative treatments.
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Affiliation(s)
| | - Ester Moreno-Artero
- Dermatology Department, Hospital Universitario Galdakao, 48960 Galdakao, Spain;
| | - Javier Romero
- Romero y Medina Dermatology Clinic, 29640 Fuengirola, Spain; (J.R.); (I.M.)
| | - Pilar Escalonilla
- Dermatology Department, Complejo Asistencial de Ávila, 05071 Ávila, Spain;
| | - Isabel Medina
- Romero y Medina Dermatology Clinic, 29640 Fuengirola, Spain; (J.R.); (I.M.)
| | - Gisela Hebe Petiti
- Dermatology Department, Consorci Sanitari Integral, Hospital Dos de Mayo, 08025 Barcelona, Spain;
| | - Pedro Redondo
- Dermatology Department, Clínica Universidad de Navarra, 28027 Madrid, Spain;
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Brito S, Heo H, Cha B, Lee SH, Park G, Kwak BM, Seong JK, Lee H, Park JH, Weon BM, Bin BH. The Slc45a4 Gene Regulates Pigmentation in a Manner Distinct from that of the OCA4 Gene Slc45a2. J Invest Dermatol 2024; 144:720-722.e5. [PMID: 37775036 DOI: 10.1016/j.jid.2023.08.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/07/2023] [Accepted: 08/15/2023] [Indexed: 10/01/2023]
Affiliation(s)
- Sofia Brito
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea; Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Hyojin Heo
- Department of Applied Bio Technology, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Byungsun Cha
- Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Sang Hun Lee
- Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Gunwoo Park
- Department of Applied Bio Technology, Graduate School, Ajou University, Suwon, Republic of Korea; Korea Bioinformation Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon, Republic of Korea
| | - Byeong-Mun Kwak
- Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea
| | - Je Kyung Seong
- Laboratory of Developmental Biology and Genomics, BK21 Plus Program for Advanced Veterinary Science, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea; Interdiscplinary Program for Bioinformatics, Seoul National University, Seoul, Republic of Korea; Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea
| | - Ho Lee
- Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea; Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Republic of Korea
| | - Ji-Hwan Park
- Korea Bioinformation Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon, Republic of Korea
| | - Byung Mook Weon
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea; Research Center for Advanced Materials Technology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Bum-Ho Bin
- Department of Applied Bio Technology, Graduate School, Ajou University, Suwon, Republic of Korea; Department of Biological Sciences, Graduate School, Ajou University, Suwon, Republic of Korea.
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Dujardin C, Habeler W, Monville C, Letourneur D, Simon-Yarza T. Advances in the engineering of the outer blood-retina barrier: From in-vitro modelling to cellular therapy. Bioact Mater 2024; 31:151-177. [PMID: 37637086 PMCID: PMC10448242 DOI: 10.1016/j.bioactmat.2023.08.003] [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: 06/05/2023] [Revised: 07/13/2023] [Accepted: 08/06/2023] [Indexed: 08/29/2023] Open
Abstract
The outer blood-retina barrier (oBRB), crucial for the survival and the proper functioning of the overlying retinal layers, is disrupted in numerous diseases affecting the retina, leading to the loss of the photoreceptors and ultimately of vision. To study the oBRB and/or its degeneration, many in vitro oBRB models have been developed, notably to investigate potential therapeutic strategies against retinal diseases. Indeed, to this day, most of these pathologies are untreatable, especially once the first signs of degeneration are observed. To cure those patients, a current strategy is to cultivate in vitro a mature oBRB epithelium on a custom membrane that is further implanted to replace the damaged native tissue. After a description of the oBRB and the related diseases, this review presents an overview of the oBRB models, from the simplest to the most complex. Then, we propose a discussion over the used cell types, for their relevance to study or treat the oBRB. Models designed for in vitro applications are then examined, by paying particular attention to the design evolution in the last years, the development of pathological models and the benefits of co-culture models, including both the retinal pigment epithelium and the choroid. Lastly, this review focuses on the models developed for in vivo implantation, with special emphasis on the choice of the material, its processing and its characterization, before discussing the reported pre-clinical and clinical trials.
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Affiliation(s)
- Chloé Dujardin
- Université Paris Cité, Université Sorbonne Paris Nord, Laboratory for Vascular Translational Science (LVTS) INSERM-U1148, 75018 Paris, France
| | - Walter Habeler
- INSERM U861, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, 91100, Corbeil-Essonnes, France
- U861, I-Stem, AFM, Université Paris-Saclay, Université D’Evry, 91100, Corbeil-Essonnes, France
- CECS, Centre D’étude des Cellules Souches, 91100, Corbeil-Essonnes, France
| | - Christelle Monville
- INSERM U861, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, 91100, Corbeil-Essonnes, France
- U861, I-Stem, AFM, Université Paris-Saclay, Université D’Evry, 91100, Corbeil-Essonnes, France
| | - Didier Letourneur
- Université Paris Cité, Université Sorbonne Paris Nord, Laboratory for Vascular Translational Science (LVTS) INSERM-U1148, 75018 Paris, France
| | - Teresa Simon-Yarza
- Université Paris Cité, Université Sorbonne Paris Nord, Laboratory for Vascular Translational Science (LVTS) INSERM-U1148, 75018 Paris, France
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Schartl M, Lu Y. Validity of Xiphophorus fish as models for human disease. Dis Model Mech 2024; 17:dmm050382. [PMID: 38299666 PMCID: PMC10855230 DOI: 10.1242/dmm.050382] [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] [Indexed: 02/02/2024] Open
Abstract
Platyfish and swordtails of the genus Xiphophorus provide a well-established model for melanoma research and have become well known for this feature. Recently, modelling approaches for other human diseases in Xiphophorus have been developed or are emerging. This Review provides a comprehensive summary of these models and discusses how findings from basic biological and molecular studies and their translation to medical research demonstrate that Xiphophorus models have face, construct and predictive validity for studying a broad array of human diseases. These models can thus improve our understanding of disease mechanisms to benefit patients.
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Affiliation(s)
- Manfred Schartl
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
- Developmental Biochemistry, Theodor-Boveri Institute, Biocenter, University of Würzburg, Würzburg 97074, Germany
| | - Yuan Lu
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
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8
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Si S, Jia X, Xu L, Qin Q, Wu J, Ji W, Dong K, Zhang X, Cao L, Wang H, Liu P, Wang R, Bai J, Fu S, Huang Y, Sun W. Identification and characterization of the compound heterozygous variants of TYR gene in a northern Chinese family with Oculocutaneous albinism type 1. Pigment Cell Melanoma Res 2023; 36:472-480. [PMID: 37403904 DOI: 10.1111/pcmr.13111] [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: 12/15/2022] [Revised: 06/01/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023]
Abstract
Oculocutaneous albinism (OCA) is a genetically heterogeneous disease and is most inherited in an autosomal recessive manner. The characteristic manifestation of OCA is due to disfunction of melanin synthesis. OCA1 is the most severe subtype of OCA and is caused by homozygous or compound heterozygous variants in tyrosinase (TYR) gene, which is the key gene for melanin synthesis. This study aimed to identify the genetic variants of a northern Chinese family with OCA1. Clinical information and peripheral blood samples were collected. PCR amplification and Sanger sequencing were used to detect the entire exons and adjacent flanking sequences of TYR gene. Functional prediction of variants was performed by various bioinformatic analyses, while the pathogenicity classification of variants was evaluated according to ACMG standards and guidelines. A missense variant NM_000372.5:c.107G > C;NP_000363.1:p.C36S was discovered in TYR gene which converted cysteine to serine. Another variant in intron, NM_000372.5:c.1037-7 T > A, also affected the function of TYR gene. We verified the pathogenicity of the intron variant with a pCAS2 mini-gene based splicing assay and found that c.1037-7 T > A led to an insertion of 5 bp upstream from the common acceptor site of exon 3, which caused a frameshift TYR:c.1037-7 T > A:p.G346Efs*11. The results showed that the compound heterozygous variants c.107G > C:p.C36S and c.1037-7 T > A:p.G346Efs*11 of TYR gene were the pathogenic variants for this OCA1 family.
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Affiliation(s)
- Shuhan Si
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Xueyuan Jia
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Lidan Xu
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Qian Qin
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Jie Wu
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Wei Ji
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Kexian Dong
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Xuelong Zhang
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Lin Cao
- Department of Hepatopancreatobiliary Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Hao Wang
- Department of Hepatopancreatobiliary Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Peng Liu
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Rongrong Wang
- McKusick-Zhang Center for Genetic Medicine, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing, China
| | - Jing Bai
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Songbin Fu
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Yun Huang
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
| | - Wenjing Sun
- Laboratory of Medical Genetics (Key Laboratory of Preservation of Human Genetic Resources and Disease Control in China, Ministry of Education), Harbin Medical University, Harbin, China
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Stroupe S, Martone C, McCann B, Juras R, Kjöllerström HJ, Raudsepp T, Beard D, Davis BW, Derr JN. Chromosome-level reference genome for North American bison (Bison bison) and variant database aids in identifying albino mutation. G3 (BETHESDA, MD.) 2023; 13:jkad156. [PMID: 37481261 PMCID: PMC10542314 DOI: 10.1093/g3journal/jkad156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/24/2023]
Abstract
We developed a highly contiguous chromosome-level reference genome for North American bison to provide a platform to evaluate the conservation, ecological, evolutionary, and population genomics of this species. Generated from a F1 hybrid between a North American bison dam and a domestic cattle bull, completeness and contiguity exceed that of other published bison genome assemblies. To demonstrate the utility for genome-wide variant frequency estimation, we compiled a genomic variant database consisting of 3 true albino bison and 44 wild-type pelage color bison. Through the examination of genomic variants fixed in the albino cohort and absent in the controls, we identified a nonsynonymous single nucleotide polymorphism (SNP) mutation on chromosome 29 in exon 3 of the tyrosinase gene (c.1114C>T). A TaqMan SNP Genotyping Assay was developed to genotype this SNP in a total of 283 animals across 29 herds. This assay confirmed the absence of homozygous variants in all animals except 7 true albino bison included in this study. In addition, the only heterozygous animals identified were 2 wild-type pelage color dams of albino offspring. Therefore, we propose that this new high-quality bison genome assembly and incipient variant database provides a highly robust and informative resource for genomics investigations for this iconic North American species.
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Affiliation(s)
- Sam Stroupe
- Department of Veterinary Pathobiology, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Carly Martone
- Department of Veterinary Pathobiology, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Blake McCann
- National Park Service, Theodore Roosevelt National Park, Medora, ND 58645, USA
| | - Rytis Juras
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Helena Josefina Kjöllerström
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Terje Raudsepp
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Donald Beard
- Texas Parks and Wildlife, Caprock Canyons State Park & Trailway, Quitaque, TX 79255, USA
| | - Brian W Davis
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
- Department of Small Animal Clinical Sciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - James N Derr
- Department of Veterinary Pathobiology, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
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Michaud V, Sequeira A, Mercier E, Lasseaux E, Plaisant C, Hadj-Rabia S, Whalen S, Bonneau D, Dieux-Coeslier A, Morice-Picard F, Coursimault J, Arveiler B, Javerzat S. Unsuspected consequences of synonymous and missense variants in OCA2 can be detected in blood cell RNA samples of patients with albinism. Pigment Cell Melanoma Res 2023. [PMID: 37650133 DOI: 10.1111/pcmr.13123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/18/2023] [Indexed: 09/01/2023]
Abstract
Oculocutaneous albinism type 2 (OCA2) is the second most frequent form of albinism and represents about 30% of OCA worldwide. As with all types of OCA, patients present with hypopigmentation of hair and skin, as well as severe visual abnormalities. We focused on a subgroup of 29 patients for whom genetic diagnosis was pending because at least one of their identified variants in or around exon 10 of OCA2 is of uncertain significance (VUS). By minigene assay, we investigated the effect of these VUS on exon 10 skipping and showed that not only intronic but also some synonymous variants can result in enhanced exon skipping. We further found that excessive skipping of exon 10 could be detected directly on blood samples of patients and of their one parent with the causal variant, avoiding invasive skin biopsies. Moreover, we show that variants, which result in lack of detectable OCA2 mRNA can be identified from blood samples as well, as shown for the most common OCA2 pathogenic missense variant c.1327G>A/p.(Val443Ile). In conclusion, blood cell RNA analysis allows testing the potential effect of any OCA2 VUS on transcription products. This should help to elucidate yet unsolved OCA2 patients and improve genetic counseling.
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Affiliation(s)
- Vincent Michaud
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, Bordeaux, France
- Department of Medical Genetics, University Hospital of Bordeaux, Bordeaux, France
| | - Angèle Sequeira
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, Bordeaux, France
| | - Elina Mercier
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, Bordeaux, France
| | - Eulalie Lasseaux
- Department of Medical Genetics, University Hospital of Bordeaux, Bordeaux, France
| | - Claudio Plaisant
- Department of Medical Genetics, University Hospital of Bordeaux, Bordeaux, France
| | - Smail Hadj-Rabia
- Department of Dermatology, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), INSERM U1163, University of Paris, Imagine Institute, AP-HP5, Necker-Enfants Malades Hospital, Paris, France
| | - Sandra Whalen
- Clinical Genetics, Centre de Référence Maladies Rares Anomalies du développement et syndromes malformatifs, APHP, Sorbonne University, Hospital Armand Trousseau, Paris, France
| | | | - Anne Dieux-Coeslier
- Clinical Genetics Department, Reference Center for Developmental Anomalies, CHU Lille, Lille, France
| | - Fanny Morice-Picard
- Pediatric Dermatology Unit, National Center for Rare Skin Disorders, University Hospital of Bordeaux, Bordeaux, France
| | - Juliette Coursimault
- Department of Genetics and Reference Center for Developmental Disorders, Normandie Univ, UNIROUEN, CHU Rouen, Inserm U1245, Rouen, France
| | - Benoît Arveiler
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, Bordeaux, France
- Department of Medical Genetics, University Hospital of Bordeaux, Bordeaux, France
| | - Sophie Javerzat
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, Bordeaux, France
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11
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Ahadi S, Wilson KA, Babenko B, McLean CY, Bryant D, Pritchard O, Kumar A, Carrera EM, Lamy R, Stewart JM, Varadarajan A, Berndl M, Kapahi P, Bashir A. Longitudinal fundus imaging and its genome-wide association analysis provide evidence for a human retinal aging clock. eLife 2023; 12:e82364. [PMID: 36975205 PMCID: PMC10110236 DOI: 10.7554/elife.82364] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Biological age, distinct from an individual's chronological age, has been studied extensively through predictive aging clocks. However, these clocks have limited accuracy in short time-scales. Here we trained deep learning models on fundus images from the EyePACS dataset to predict individuals' chronological age. Our retinal aging clocking, 'eyeAge', predicted chronological age more accurately than other aging clocks (mean absolute error of 2.86 and 3.30 years on quality-filtered data from EyePACS and UK Biobank, respectively). Additionally, eyeAge was independent of blood marker-based measures of biological age, maintaining an all-cause mortality hazard ratio of 1.026 even when adjusted for phenotypic age. The individual-specific nature of eyeAge was reinforced via multiple GWAS hits in the UK Biobank cohort. The top GWAS locus was further validated via knockdown of the fly homolog, Alk, which slowed age-related decline in vision in flies. This study demonstrates the potential utility of a retinal aging clock for studying aging and age-related diseases and quantitatively measuring aging on very short time-scales, opening avenues for quick and actionable evaluation of gero-protective therapeutics.
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Affiliation(s)
- Sara Ahadi
- Google ResearchMountain ViewUnited States
| | | | | | | | | | | | - Ajay Kumar
- Department of Biophysics, Post Graduate Institute of Medical Education and ResearchChandigarhIndia
| | | | - Ricardo Lamy
- Department of Ophthalmology, Zuckerberg San Francisco General Hospital and Trauma CenterSan FranciscoUnited States
| | - Jay M Stewart
- Department of Ophthalmology, University of California, San FranciscoSan FranciscoUnited States
| | | | | | - Pankaj Kapahi
- Buck Institute for Research on AgingNovatoUnited States
| | - Ali Bashir
- Google ResearchMountain ViewUnited States
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12
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Beyers WC, Detry AM, Di Pietro SM. OCA7 is a melanosome membrane protein that defines pigmentation by regulating early stages of melanosome biogenesis. J Biol Chem 2022; 298:102669. [PMID: 36334630 DOI: 10.1016/j.jbc.2022.102669] [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: 06/15/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022] Open
Abstract
Mutations in C10orf11 (oculocutaneous albinism type 7 [OCA7]) cause OCA, a disorder that presents with hypopigmentation in skin, eyes, and hair. The OCA7 pathophysiology is unknown, and there is virtually no information on the OCA7 protein and its cellular function. Here, we discover that OCA7 localizes to the limiting membrane of melanosomes, the specialized pigment cell organelles where melanin is synthesized. We demonstrate that OCA7 is recruited through interaction with a canonical effector-binding surface of melanosome proteins Rab32 and Rab38. Using newly generated OCA7-KO MNT1 cells, we show OCA7 regulates overall melanin levels in a melanocyte autonomous manner by controlling melanosome maturation. Importantly, we found that OCA7 regulates premelanosome protein (PMEL) processing, impacting fibrillation and the striations that define transition from melanosome stage I to stage II. Furthermore, the melanosome lumen of OCA7-KO cells displays lower pH than control cells. Together, our results reveal that OCA7 regulates pigmentation through two well-established determinants of melanosome biogenesis and function, PMEL processing, and organelle pH.
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Affiliation(s)
- Wyatt C Beyers
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Anna M Detry
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Santiago M Di Pietro
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA.
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13
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Wong EWN, Cheng SS, Woo TT, Lam RF, Lai FH. Concurrent PANK2 and OCA2 variants in a patient with retinal dystrophy, hypopigmented irides and neurodegeneration. Ophthalmic Genet 2022:1-5. [DOI: 10.1080/13816810.2022.2135107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Eva Wai Nam Wong
- Department of Ophthalmology, Caritas Medical Centre, Sham Shui Po, Hong Kong
| | | | - Tiffany T.Y. Woo
- Department of Ophthalmology, Caritas Medical Centre, Sham Shui Po, Hong Kong
| | - Robert F. Lam
- Department of Ophthalmology, Caritas Medical Centre, Sham Shui Po, Hong Kong
| | - Frank H.P. Lai
- Department of Ophthalmology, Caritas Medical Centre, Sham Shui Po, Hong Kong
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14
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Yan J, Liu B, Cao Z, Chen L, Liang Z, Wang M, Liu W, Lin Y, Jiang B. Cytological, genetic and transcriptomic characterization of a cucumber albino mutant. FRONTIERS IN PLANT SCIENCE 2022; 13:1047090. [PMID: 36340338 PMCID: PMC9630852 DOI: 10.3389/fpls.2022.1047090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Photosynthesis, a fundamental process for plant growth and development, is dependent on chloroplast formation and chlorophyll synthesis. Severe disruption of chloroplast structure results in albinism of higher plants. In the present study, we report a cucumber albino alc mutant that presented white cotyledons under normal light conditions and was unable to produce first true leaf. Meanwhile, alc mutant could grow creamy green cotyledons under dim light conditions but died after exposure to normal light irradiation. No chlorophyll and carotenoid were detected in the alc mutant grown under normal light conditions. Using transmission electron microscopy, impaired chloroplasts were observed in this mutant. The genetic analysis indicated that the albino phenotype was recessively controlled by a single locus. Comparative transcriptomic analysis between the alc mutant and wild type revealed that genes involved in chlorophyll metabolism and the methylerythritol 4-phosphate pathway were affected in the alc mutant. In addition, three genes involved in chloroplast development, including two FtsH genes and one PPR gene, were found to have negligible expression in this mutant. The quality of RNA sequencing results was further confirmed by real-time quantitative PCR analysis. We also examined 12 homologous genes from alc mutant in other plant species, but no genetic variation in the coding sequences of these genes was found between alc mutant and wild type. Taken together, we characterized a cucumber albino mutant with albinism phenotype caused by chloroplast development deficiency and this mutant can pave way for future studies on plastid development.
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Affiliation(s)
- Jinqiang Yan
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- Guangdong Key Laboratory for New Technology Research of Vegetables, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Bin Liu
- Hami-melon Research Center, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Zhenqiang Cao
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Lin Chen
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- Guangdong Key Laboratory for New Technology Research of Vegetables, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Zhaojun Liang
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Min Wang
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- Guangdong Key Laboratory for New Technology Research of Vegetables, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Wenrui Liu
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- Guangdong Key Laboratory for New Technology Research of Vegetables, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Yu'e Lin
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Biao Jiang
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- Guangdong Key Laboratory for New Technology Research of Vegetables, Guangdong Academy of Agricultural Sciences, Guangzhou, China
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15
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Marek-Yagel D, Abudi-Sinreich S, Macarov M, Veber A, Shalva N, Philosoph AM, Pode-Shakked B, Malicdan MCV, Anikster Y. Oculocutaneous albinism and bleeding diathesis due to a novel deletion in the HPS3 gene. Front Genet 2022; 13:936064. [PMID: 36046236 PMCID: PMC9420964 DOI: 10.3389/fgene.2022.936064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/07/2022] [Indexed: 11/13/2022] Open
Abstract
Hermansky–Pudlak syndrome (HPS) is a group of rare autosomal recessive disorders characterized by oculocutaneous albinism (OCA) and bleeding diathesis. To date, 11 HPS types have been reported (HPS-1 to HPS-11), each defined by disease-causing variants in specific genes. Variants in the HPS1 gene were found in approximately 15% of HPS patients, most of whom harbor the Puerto Rican founder mutation. In this study, we report six affected individuals from three nonconsanguineous families of Ashkenazi Jewish descent, who presented with OCA and multiple ecchymoses and had normal platelet number and size. Linkage analysis indicated complete segregation to HPS3. Sequencing of the whole coding region and the intron boundaries of HPS3 revealed a heterozygous c.1163+1G>A variant in all six patients. Long-range PCR amplification revealed that all affected individuals also carry a 14,761bp deletion that includes the 5′UTR and exon 1 of HPS3, encompassing regions with long interspersed nuclear elements. The frequency of the c.1163+1G>A splice site variant was found to be 1:200 in the Ashkenazi Jewish population, whereas the large deletion was not detected in 300 Ashkenazi Jewish controls. These results present a novel HPS3 deletion mutation and suggest that the prevalence of HPS-3 in Ashkenazi Jews is more common than previously thought.
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Affiliation(s)
- Dina Marek-Yagel
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Shachar Abudi-Sinreich
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD, United States
| | - Michal Macarov
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Alvit Veber
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
| | - Nechama Shalva
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
| | - Amit Mary Philosoph
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
| | - Ben Pode-Shakked
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Talpiot Medical Leadership Program, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
| | - May Christine V. Malicdan
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD, United States
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director and National Human Genome Research Institute, Bethesda, MD, United States
| | - Yair Anikster
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Ramat Gan, Tel-Hahsomer, Israel
- *Correspondence: Yair Anikster,
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16
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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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17
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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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18
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Toufeeq S, Gottlob I, Tu Z, Proudlock FA, Pilat A. Abnormal Retinal Vessel Architecture in Albinism and Idiopathic Infantile Nystagmus. Invest Ophthalmol Vis Sci 2022; 63:33. [PMID: 35616929 PMCID: PMC9150830 DOI: 10.1167/iovs.63.5.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Infantile nystagmus syndrome (INS) causes altered visual development and can be associated with abnormal retinal structure, to which vascular development of the retina is closely related. Abnormal retinal vasculature has previously been noted in albinism but not idiopathic infantile nystagmus. We compared the number and diameter of retinal vessels in participants with albinism (PWA) and idiopathic infantile nystagmus (PWIIN) with controls. Methods Fundus photography data from 24 PWA, 10 PWIIN, and 34 controls was analyzed using Automated Retinal Image Analyzer (ARIA) software on a field of analysis centered on the optic disc, the annulus of which extended between 4.2 mm and 8.4 mm in diameter. Results Compared with controls, the mean number of arterial branches was reduced by 24% in PWA (15.5 vs. 20.3, P < 0.001), and venous branches were reduced in both PWA (29%; 12.9 vs. 18.2, P < 0.001) and PWIIN (17%; 15.1 vs. 18.2, P = 0.024). PWA demonstrated 7% thinner "primary" (before branching) arteries (mean diameter: 75.39 µm vs. 80.88 µm, P = 0.043), and 13% thicker (after branching) "secondary" veins (66.72 µm vs. 59.01 µm in controls, P = 0.009). Conclusions PWA and PWIIN demonstrated reduced retinal vessel counts and arterial diameters compared with controls. These changes in the superficial retinal vascular network may be secondary to underdevelopment of the neuronal network, which guides vascular development and is also known to be disrupted in INS.
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Affiliation(s)
- Shafak Toufeeq
- Oxford Eye Hospital, Level LG1 John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, United Kingdom
| | - Irene Gottlob
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
| | - Zhanhan Tu
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
| | - Frank A. Proudlock
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
| | - Anastasia Pilat
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
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19
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Xiao Y, Zhou C, Xie H, Huang S, Wang J, Liu S. NGS-based targeted sequencing identified two novel variants in Southwestern Chinese families with oculocutaneous albinism. BMC Genomics 2022; 23:332. [PMID: 35488210 PMCID: PMC9055679 DOI: 10.1186/s12864-022-08597-3] [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: 11/09/2021] [Accepted: 04/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a group of heterogeneous genetic diseases characterized by a reduction or complete lack of pigmentation in the hair, skin, and eyes. It is associated with reduced visual acuity, nystagmus, photophobia, and strabismus. OCA type 1 (OCA1) and type 2 (OCA2) are caused by mutations in the tyrosinase (TYR) and OCA2 genes, which are responsible for most cases of OCA. The present study aimed to identify the mutational spectra of 18 southwest Chinese probands with OCA. RESULTS We used a skin disease-targeted panel to sequence more than 400 genes, including 23 genes (TYR, OCA2, AP3B1, BLOC1S3, BLOC1S6, C10orf11, DTNBP1, FRMD7, GPR143, HPS1, HPS3, HPS4, HPS5, HPS6, LYST, MC1R, MITF, MLPH, MYO5A, RAB27A, SLC24A5, SLC45A2, TYRP1) associated with syndromic and non-syndromic albinism. The targeted panel was applied to 18 patients from southwest China, nine (50%) patients were diagnosed with OCA1, and nine (50%) were diagnosed with OCA2. Our data indicate that OCA1 and OCA2, the most common subtypes, probably have the same prevalence in southwest China. In total, we identified 26 variants in TYR and OCA2 from 18 OCA cases using the NGS technology, including 24 variants presented in the Human Gene Mutation Database Professional (HGMD) and two novel variants, c.559_560insCATTATTATGTGTCAAATTATCCCC in TYR and c.1514 T > C in OCA2, which have not been previously reported. According to the American College of Medical Genetics and Genomics (ACMG) classification, c.559_560insCATTATTATGTGTCAAATTATCCCC (p.G190Cfs*12) is classified as a pathogenic variant, and c.1514 T > C (p.F505S) is evaluated as a likely pathogenic variant. CONCLUSIONS Two novel variants were identified which will expand the mutational spectra of TYR and OCA2. The results of the present study may have implications for genetic counseling, carrier screening, and clinical management of the disease.
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Affiliation(s)
- Yuanyuan Xiao
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Cong Zhou
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Hanbing Xie
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Shuang Huang
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Jing Wang
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China. .,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China.
| | - Shanling Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China. .,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China.
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20
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Zebrafish Syndromic Albinism Models as Tools for Understanding and Treating Pigment Cell Disease in Humans. Cancers (Basel) 2022; 14:cancers14071752. [PMID: 35406524 PMCID: PMC8997128 DOI: 10.3390/cancers14071752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/18/2022] [Accepted: 03/26/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Zebrafish (Danio rerio) is an emerging model for studying many diseases, including disorders originating in black pigment cells, melanocytes. In this review of the melanocyte literature, we discuss the current knowledge of melanocyte biology relevant to understanding different forms of albinism and the potential of the zebrafish model system for finding novel mechanisms and treatments. Abstract Melanin is the pigment that protects DNA from ultraviolet (UV) damage by absorbing excess energy. Melanin is produced in a process called melanogenesis. When melanogenesis is altered, diseases such as albinism result. Albinism can result in an increased skin cancer risk. Conversely, black pigment cell (melanocyte) development pathways can be misregulated, causing excessive melanocyte growth that leads to melanoma (cancer of melanocytes). Zebrafish is an emerging model organism used to study pigment disorders due to their high fecundity, visible melanin development in melanophores (melanocytes in mammals) from 24 h post-fertilization, and conserved melanogenesis pathways. Here, we reviewed the conserved developmental pathways in zebrafish melanophores and mammalian melanocytes. Additionally, we summarized the progress made in understanding pigment cell disease and evidence supporting the strong potential for using zebrafish to find novel treatment options for albinism.
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21
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Apgar TL, Sanders CR. Compendium of causative genes and their encoded proteins for common monogenic disorders. Protein Sci 2022; 31:75-91. [PMID: 34515378 PMCID: PMC8740837 DOI: 10.1002/pro.4183] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 01/19/2023]
Abstract
A compendium is presented of inherited monogenic disorders that have a prevalence of >1:20,000 in the human population, along with their causative genes and encoded proteins. "Simple" monogenic diseases are those for which the clinical features are caused by mutations impacting a single gene, usually in a manner that alters the sequence of the encoded protein. Of course, for a given "monogenic disorder", there is sometimes more than one potential disease gene, mutations in any one of which is sufficient to cause phenotypes of that disorder. Disease-causing mutations for monogenic disorders are usually passed on from generation to generation in a Mendelian fashion, and originate from spontaneous (de novo) germline founder mutations. In the past monogenic disorders have often been written off as targets for drug discovery because they sometimes are assumed to be rare disorders, for which the meager projected financial payoff of drug discovery and development has discouraged investment. However, not all monogenic diseases are rare. Here, we report that that currently available data identifies 72 disorders with a prevalence of at least 1 in 20,000 humans. For each, we tabulate the gene(s) for which mutations cause the spectrum of phenotypes associated with that disorder. We also identify the gene and protein that most commonly causes each disease. 34 of these disorders are caused exclusively by mutations in only a single gene and encoded protein.
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Affiliation(s)
- Tucker L. Apgar
- Department of Biochemistry and Center for Structural BiologyVanderbilt University School of Medicine Basic SciencesNashvilleTennesseeUSA
| | - Charles R. Sanders
- Department of Biochemistry and Center for Structural BiologyVanderbilt University School of Medicine Basic SciencesNashvilleTennesseeUSA
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22
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Karim S, Saharti S, Alganmi N, Mirza Z, Alfares A, Turkistany S, Al-Attas M, Noureldin H, Al Sakkaf K, Abusamra H, Al-Qahtani M, Abuzenadah A. Two Novel Homozygous HPS6 Mutations (Double Mutant) Identified by Whole-Exome Sequencing in a Saudi Consanguineous Family Suspected for Oculocutaneous Albinism. Life (Basel) 2021; 12:life12010014. [PMID: 35054407 PMCID: PMC8779141 DOI: 10.3390/life12010014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 11/28/2022] Open
Abstract
Background: Oculocutaneous albinism (OCA) is an autosomal recessive disorder of low or missing pigmentation in the eyes, hair, and skin. Multiple types of OCA, including Hermansky-Pudlak syndrome 6 (HPS6), are distinguished by their genetic cause and pigmentation pattern. HPS6 is characterized by OCA, nose bleeding due to platelet dysfunction, and lysosome storage defect. To date, 25 disease-associated mutations have been reported in the HPS6 gene. Methods: DNA was extracted from proband, and whole-exome sequencing (WES) was performed using the Illumina NovaSeq platform. Bioinformatic analysis was done with a custom-designed filter pipeline to detect the causative variant. We did Sanger sequencing to confirm the candidate variant and segregation analysis, and protein-based structural analysis to evaluate the functional impact of variants. Result: Proband-based WES identified two novel homozygous mutations in HPS6 (double mutation, c.1136C>A and c.1789delG) in an OCA suspect. Sanger sequencing confirmed the WES results. Although no platelet and/or lysosome storage defect was detected in the patient or family, an oculocutaneous albinism diagnosis was established based on the HPS6 mutations. Structural analysis revealed the transformation of abnormalities at protein level for both nonsense and frameshift mutations in HPS6. Conclusion: To the best of our knowledge, the double mutation in HPS6 (p.Ser379Ter and p.Ala597GlnfsTer16) represents novel pathogenic variants, not described previously, which we report for the first time in the Saudi family. In silico analyses showed a significant impact on protein structure. WES should be used to identify HPS6 and/or other disease-associated genetic variants in Saudi Arabia, particularly in consanguineous families.
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Affiliation(s)
- Sajjad Karim
- Center of Excellence in Genomic Medicine Research, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-Q.); (A.A.)
- Department of Medical Lab Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
- Correspondence: ; Tel.: +966-557581741
| | - Samah Saharti
- Department of Pathology, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
| | - Nofe Alganmi
- Computer Science Department, Faculty of Computing and Information Technology, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
| | - Zeenat Mirza
- Department of Medical Lab Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
- King Fahd Medical Research Center, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ahmed Alfares
- Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Riyadh 11426, Saudi Arabia;
| | - Shereen Turkistany
- Center of Innovation in Personalized Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
| | - Manal Al-Attas
- Roya Specialized Medical Laboratories, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-A.); (H.N.); (K.A.S.); (H.A.)
| | - Hend Noureldin
- Roya Specialized Medical Laboratories, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-A.); (H.N.); (K.A.S.); (H.A.)
| | - Khadega Al Sakkaf
- Roya Specialized Medical Laboratories, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-A.); (H.N.); (K.A.S.); (H.A.)
| | - Heba Abusamra
- Roya Specialized Medical Laboratories, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-A.); (H.N.); (K.A.S.); (H.A.)
| | - Mohammed Al-Qahtani
- Center of Excellence in Genomic Medicine Research, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-Q.); (A.A.)
| | - Adel Abuzenadah
- Center of Excellence in Genomic Medicine Research, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-Q.); (A.A.)
- Department of Medical Lab Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
- King Fahd Medical Research Center, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Roya Specialized Medical Laboratories, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (M.A.-A.); (H.N.); (K.A.S.); (H.A.)
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23
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Integrative mRNA-miRNA interaction analysis reveals the molecular mechanism of skin color variation between wild-type and yellow mutant rainbow trout (Oncorhynchus mykiss). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2021; 40:100914. [PMID: 34653947 DOI: 10.1016/j.cbd.2021.100914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 12/26/2022]
Abstract
Rainbow trout (Oncorhynchus mykiss) is an important economic fish in China. Skin color affects the economic value of trout. However, the molecular mechanism of the skin color variation between wild-type (WR) and yellow mutant rainbow trout (YR) is unclear. We sequenced mRNAs and miRNAs of dorsal skin to identify key color variation-associated mRNAs and miRNAs between WR and YR. Overall, 2060 out of 3625 differentially expressed genes were upregulated in YR, and 196 out of 275 differentially expressed miRNAs were downregulated in WR. We identified three key YR-upregulated genes related to the formation of xanthophores (GCH1, SLC2A11, and SOX10). Interestingly, several genes related to melanogenesis (TYR, TYRP1, TYRP2, MC1R, MITF, PMEL, SLC45A2, and OCA2) were downregulated in WR. Integrated analysis identified five miRNAs that target at least two skin color-related genes (miR-495-y, miR-543-y, miR-665-z, miR-433-y, and miR-382-x). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of target genes identified noncoding RNA metabolic process as the most significantly enriched GO term, and several metabolic pathways associated with skin color were enriched significantly, such as tyrosine metabolism, histidine metabolism, and vitamin B6 metabolism. Quantitative real-time PCR of selected mRNAs and miRNAs validated the reliability of the integrated analysis. This study provides in-depth insights into the molecular mechanism of skin color variation between WR and YR, which will accelerate the genetic selection and breeding of rainbow trout with consumer-favored traits.
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24
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Moreno-Artero E, Morice-Picard F, Bremond-Gignac D, Drumare-Bouvet I, Duncombe-Poulet C, Leclerc-Mercier S, Dufresne H, Kaplan J, Jouanne B, Arveiler B, Taieb A, Hadj-Rabia S. Management of albinism: French guidelines for diagnosis and care. J Eur Acad Dermatol Venereol 2021; 35:1449-1459. [PMID: 34042219 DOI: 10.1111/jdv.17275] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 03/22/2021] [Indexed: 12/12/2022]
Abstract
Albinism is a worldwide genetic disorder caused by mutations in at least 20 genes, identified to date, that affect melanin production or transport in the skin, hair and eyes. Patients present with variable degrees of diffuse muco-cutaneous and adnexal hypopigmentation, as well as ocular features including nystagmus, misrouting of optic nerves and foveal hypoplasia. Less often, albinism is associated with blood, immunological, pulmonary, digestive and/or neurological anomalies. Clinical and molecular characterizations are essential in preventing potential complications. Disease-causing mutations remain unknown for about 25% of patients with albinism. These guidelines have been developed for the diagnosis and management of syndromic and non-syndromic forms of albinism, based on a systematic review of the scientific literature. These guidelines comprise clinical and molecular characterization, diagnosis, therapeutic approach and management.
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Affiliation(s)
- E Moreno-Artero
- Department of Dermatology, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Hôpital Universitaire Necker- Enfants Malades, Assistance Publique - Hôpitaux de Paris-Centre (AP-HP5), Paris, France
| | - F Morice-Picard
- Pediatric Dermatology Unit, National Centre for Rare Skin Disorders, Hôpital Pellegrin-Enfants, CHU de Bordeaux, Bordeaux, France
| | - D Bremond-Gignac
- Department of Ophthalmology, Reference Centre for Rare Ocular Diseases (OPHTARA), Hôpital Necker-Enfants Malades, APHP5, Paris, France.,Université de Paris-Centre, Paris, France
| | - I Drumare-Bouvet
- Service d'exploration de la vision et neuro-ophtalmologie, CHRU de Lille, Lille, France
| | | | - S Leclerc-Mercier
- Department of Pathology, Hôpital Necker-Enfants Malades, APHP5, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Université de Paris-Centre, Paris, France
| | - H Dufresne
- Department of Dermatology, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Hôpital Universitaire Necker- Enfants Malades, Assistance Publique - Hôpitaux de Paris-Centre (AP-HP5), Paris, France.,Service Social Pédiatrique, Hôpital Necker-Enfants Malades, APHP5, Université de Paris-Centre, Paris, France
| | - J Kaplan
- Laboratory of Genetics in Ophthalmology, Imagine Institute, Paris, France
| | - B Jouanne
- French Association for Albinism (Genespoir), Rennes, France
| | - B Arveiler
- Molecular Genetics Laboratory, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Bordeaux, France
| | - A Taieb
- Pediatric Dermatology Unit, National Centre for Rare Skin Disorders, Hôpital Pellegrin-Enfants, CHU de Bordeaux, Bordeaux, France
| | - S Hadj-Rabia
- Department of Dermatology, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Hôpital Universitaire Necker- Enfants Malades, Assistance Publique - Hôpitaux de Paris-Centre (AP-HP5), Paris, France.,Université de Paris-Centre, Paris, France
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25
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Lee AY. Skin Pigmentation Abnormalities and Their Possible Relationship with Skin Aging. Int J Mol Sci 2021; 22:ijms22073727. [PMID: 33918445 PMCID: PMC8038212 DOI: 10.3390/ijms22073727] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/24/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022] Open
Abstract
Skin disorders showing abnormal pigmentation are often difficult to manage because of their uncertain etiology or pathogenesis. Abnormal pigmentation is a common symptom accompanying aging skin. The association between skin aging and skin pigmentation abnormalities can be attributed to certain inherited disorders characterized by premature aging and abnormal pigmentation in the skin and some therapeutic modalities effective for both. Several molecular mechanisms, including oxidative stress, mitochondrial DNA mutations, DNA damage, telomere shortening, hormonal changes, and autophagy impairment, have been identified as involved in skin aging. Although each of these skin aging-related mechanisms are interconnected, this review examined the role of each mechanism in skin hyperpigmentation or hypopigmentation to propose the possible association between skin aging and pigmentation abnormalities.
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Affiliation(s)
- Ai-Young Lee
- Department of Dermatology, College of Medicine, Dongguk University Ilsan Hospital, 814 Siksa-dong, Ilsandong-gu, Goyang-si 410-773, Gyeonggi-do, Korea
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26
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Shahrisa A, Nikkhah M, Shirzad H, Behzadi R, Sadeghizadeh M. Enhancing Catecholase Activity of a Recombinant Human Tyrosinase Through Multiple Strategies. IRANIAN JOURNAL OF BIOTECHNOLOGY 2021; 18:e2310. [PMID: 33542935 PMCID: PMC7856396 DOI: 10.30498/ijb.2020.137293.2310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background: Tyrosinases are copper-containing enzymes that initiate the melanin synthesis. They catalyze the direct oxidation of L-tyrosine or L-DOPA into L-DOPAquinone. Objectives: In present study, we aimed to obtain a recombinant tyrosinase with enhanced catecholase activity through site-directed mutagenesis. Materials and Methods: The coding sequence of human tyrosinase along with native signal sequence was cloned into pET-28a (+).
BL-21 was used as expression host and recombinant protein was purified by Ni-NTA resins.
Site-directed mutagenesis was performed on M374 residue to achieve four mutants: M374D, M374T, M374K and M374R. Chloride ions (Cl-)
were removed from all solutions, and an extra amount of Cu2+ ions was added to recombinant tyrosinases by a novel technique
during the purification process. Removal of Cl- ions and addition of extra Cu2+ ions tripled catecholase activity
of the recombinant protein. Therefore, all mutants were obtained under similar conditions. Results: Although all the mutants presented higher catecholase activity in comparison to the wild-type enzyme,
a significant increase in catecholase activity of the M374D mutant was observed ‒ 13.2-fold. In silico modeling
suggested that a de novo hydrogen bond occurs between side chain carboxyl oxygens of D374 and H367 in M374D.
In the wild-type tyrosinase, the peptide oxygen atom of M374 is responsible for hydrogen bonding with H367. Conclusions: Our data suggests that M374D mutational variant has applications in different areas such as agriculture, industry, and medicine.
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Affiliation(s)
- Arman Shahrisa
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maryam Nikkhah
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Hadi Shirzad
- Department of Human Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Roudabeh Behzadi
- Department of Biology, Central Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Majid Sadeghizadeh
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
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27
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Xu C, Xiang Y, Li H, Xu Y, Mao Y, Zhou L, Xu X, Tang S. Genetic analysis and prenatal diagnosis of 20 Chinese families with oculocutaneous albinism. J Clin Lab Anal 2020; 35:e23647. [PMID: 33124154 PMCID: PMC7891544 DOI: 10.1002/jcla.23647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 12/27/2022] Open
Abstract
Background Oculocutaneous albinism (OCA) is a group of heterogeneous genetic disorders characterized by abnormal melanin synthesis in the hair, skin, and eyes. OCA exhibits obvious genetic and phenotypic heterogeneity. Molecular diagnosis of causal genes can be of help in the classification of OCA subtypes and the study of OCA pathogenesis. Methods In this study, Sanger sequencing and whole exome sequencing were used to genetically diagnose 20 nonconsanguineous Chinese OCA patients. In addition, prenatal diagnosis was provided to six OCA families. Results Variants of TYR, OCA2, and HPS1 were detected in 85%, 10%, and 5% of affected patients, respectively. A total of 21 distinct variants of these three genes were identified. Exons 1 and 2 were the hotspot regions of the TYR variants, and c.895C > A and c.896G > A were the hotspot variants. We also found seven novel variants: c.731G > A, c.741C > A, c.867C > A, and c.1037‐2A > T in TYR, c.695dupT and c.1054A > G in OCA2, and c.9C > A in HPS1. Genetic tests on six fetuses revealed three carrier fetuses, two normal fetuses, and one affected fetus. The follow‐up results after birth were consistent with the results of prenatal diagnosis (one fetus terminated during pregnancy was not followed up). Conclusions This study expands our understanding of the genotypic spectrum of the Chinese OCA population. The findings indicate that prenatal diagnosis can provide important information for genetic counseling.
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Affiliation(s)
- Chenyang Xu
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Yanbao Xiang
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Huanzheng Li
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Yunzhi Xu
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Yijian Mao
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Lili Zhou
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Xueqin Xu
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Shaohua Tang
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China.,Key Laboratory of Medical Genetic, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, China
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28
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Current and emerging treatments for albinism. Surv Ophthalmol 2020; 66:362-377. [PMID: 33129801 DOI: 10.1016/j.survophthal.2020.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 10/07/2020] [Accepted: 10/21/2020] [Indexed: 12/24/2022]
Abstract
Albinism is a group of rare inherited disorders arising from impairment of melanin biosynthesis. The reduction of melanin synthesis leads to hypopigmentation of the skin and eyes. A wide range of ophthalmic manifestations arise from albinism, including reduction of visual acuity, nystagmus, strabismus, iris translucency, foveal hypoplasia, fundus hypopigmentation, and abnormal decussation of retinal ganglion cell axons at the optic chiasm. Currently, albinism is incurable, and treatment aims either surgically or pharmacologically to optimize vision and protect the skin; however, novel therapies that aim to directly address the molecular errors of albinism, such as l-dihydroxyphenylalanine and nitisinone, are being developed and have entered human trials though with limited success. Experimental gene-based strategies for editing the genetic errors in albinism have also met early success in animal models. The emergence of these new therapeutic modalities represents a new era in the management of albinism. We focus on the known genetic subtypes, clinical assessment, and existing and emerging therapeutic options for the nonsyndromic forms of albinism.
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29
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Patel N, Bhadarka HK, Vaniawala S, Patel A. A Successful Case for Deselection of Albino Embryo and Live Birth of Albinism-Free Healthy Baby Followed by PGT-M. J Hum Reprod Sci 2020; 13:245-248. [PMID: 33311913 PMCID: PMC7727887 DOI: 10.4103/jhrs.jhrs_38_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 04/20/2020] [Indexed: 11/09/2022] Open
Abstract
In recent years, Preimplantation genetic testing for monogenic disorders (PGT-M) has gained a lot of focus in the field of assisted reproduction technology, various studies have been published in support of it and many are opposing its role. It has been criticized due to many ethical as well as scientific reasons, but there is no doubt that PGT-M has been one of the most important breakthroughs in in vitro fertilization. A critical aspect of this technology is the possibility that the biopsy itself can adversely affect the quality of embryo and compulsion of embryo freezing. Oculocutaneous albinism (OCA) is a condition which is related to skin, hair, eye color (pigments), where affected individuals typically have very fair skin and white- or light-colored hair. These patients are prone to skin cancers on prolonged sun exposure. It also reduces the pigmentation of the colored part of the eyes (the iris) and the light-sensitive tissue at the back of the eye (the retina). People with this condition usually have problem in vision such as reduced sharpness, involuntary eye movements, and photophobia. Here, we report the successful use of PGT-M and a novel protocol for the preimplantation genetic diagnosis of OCA following trophectoderm cell biopsy from blastocysts and the birth of a healthy infant to a couple having previously affected child.
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Affiliation(s)
- Nayana Patel
- Department of IVF, Akanksha Hospital and Research Institute, Anand, India
| | - Harsha K Bhadarka
- Department of IVF, Akanksha Hospital and Research Institute, Anand, India
| | | | - Arpita Patel
- Department of IVF, Akanksha Hospital and Research Institute, Anand, India
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30
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Kidd KK, Pakstis AJ, Donnelly MP, Bulbul O, Cherni L, Gurkan C, Kang L, Li H, Yun L, Paschou P, Meiklejohn KA, Haigh E, Speed WC. The distinctive geographic patterns of common pigmentation variants at the OCA2 gene. Sci Rep 2020; 10:15433. [PMID: 32963319 PMCID: PMC7508881 DOI: 10.1038/s41598-020-72262-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 08/17/2020] [Indexed: 11/25/2022] Open
Abstract
Oculocutaneous Albinism type 2 (OCA2) is a gene of great interest because of genetic variation affecting normal pigmentation variation in humans. The diverse geographic patterns for variant frequencies at OCA2 have been evident but have not been systematically investigated, especially outside of Europe. Here we examine population genetic variation in and near the OCA2 gene from a worldwide perspective. The very different patterns of genetic variation found across world regions suggest strong selection effects may have been at work over time. For example, analyses involving the variants that affect pigmentation of the iris argue that the derived allele of the rs1800407 single nucleotide polymorphism, which produces a hypomorphic protein, may have contributed to the previously demonstrated positive selection in Europe for the enhancer variant responsible for light eye color. More study is needed on the relationships of the genetic variation at OCA2 to variation in pigmentation in areas beyond Europe.
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Affiliation(s)
- Kenneth K Kidd
- Professor Emeritus, Department of Genetics, Yale University School of Medicine, P.O. Box 208005, New Haven, CT, 06520-8005, USA.
| | - Andrew J Pakstis
- Professor Emeritus, Department of Genetics, Yale University School of Medicine, P.O. Box 208005, New Haven, CT, 06520-8005, USA
| | - Michael P Donnelly
- Professor Emeritus, Department of Genetics, Yale University School of Medicine, P.O. Box 208005, New Haven, CT, 06520-8005, USA.,Biological and Environmental Sciences, Troy University, Dothan, AL, 36303, USA
| | - Ozlem Bulbul
- Institute of Forensic Science, Istanbul University-Cerrahpasa, Istanbul, 34500, Turkey
| | - Lotfi Cherni
- Laboratory of Genetics, Immunology and Human Pathologies, Faculty of Sciences of Tunis, University of Tunis El Manar, 2092, Tunis, Tunisia.,Higher Institute of Biotechnology of Monastir, Monastir University, 5000, Monastir, Tunisia
| | - Cemal Gurkan
- Turkish Cypriot DNA Laboratory, Committee on Missing Persons in Cyprus Turkish Cypriot Member Office, Nicosia, North Cyprus), Turkey.,Dr. Fazıl Küçük Faculty of Medicine, Eastern Mediterranean University, Famagusta (North Cyprus), Turkey
| | - Longli Kang
- Key Laboratory forMolecular GeneticMechanisms and Intervention Research On High Altitude Disease of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, 712082, Shaanxi, China.,Key Laboratory of High Altitude Environment and Genes Related To Disease of Tibet Ministry of Education, School of Medicine, Xizang Minzu University, Xianyang, 712082, Shaanxi, China
| | - Hui Li
- MOE State Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China
| | - Libing Yun
- Institute of Forensic Medicine, West China College of Preclinical and Forensic Medicine, Sichuan University, No.16. Section 3. RenMin Nan Road, Chengdu, 610041, Sichuan, China
| | - Peristera Paschou
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Kelly A Meiklejohn
- Department of Population Health and Pathobiology, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA
| | - Eva Haigh
- Professor Emeritus, Department of Genetics, Yale University School of Medicine, P.O. Box 208005, New Haven, CT, 06520-8005, USA
| | - William C Speed
- Professor Emeritus, Department of Genetics, Yale University School of Medicine, P.O. Box 208005, New Haven, CT, 06520-8005, USA
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Bibi N, Ullah A, Darwesh L, Khan W, Khan T, Ullah K, Khan B, Ahmad W. Identification and Computational Analysis of Novel TYR and SLC45A2 Gene Mutations in Pakistani Families With Identical Non-syndromic Oculocutaneous Albinism. Front Genet 2020; 11:749. [PMID: 32849781 PMCID: PMC7385404 DOI: 10.3389/fgene.2020.00749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/23/2020] [Indexed: 12/19/2022] Open
Abstract
Non-syndromic oculocutaneous albinism (nsOCA) is an inherited disorder of melanin biosynthesis with autosomal recessive mode of inheritance, presenting either hypopigmented or depigmented skin, hair, and eyes. It is genetically heterogeneous with seven loci (OCA1–OCA7) reported to date. In the present study, we have reported three consanguineous families (A, B, C) presenting identical nsOCA phenotypes. Sanger sequencing revealed a novel [NM_000372.5: c.826 T > C, p.(Cys276Arg)] and a recurrent variant [NM_000372.5: c.832C > T, p.(Arg278∗)] in tyrosinase (TYR) in families A and B, respectively. Microsatellite marker-based homozygosity mapping linked family C to OCA4. Sequence analysis identified a novel insertion variant (NM_016180.5: c.1331_1332insA) in the SLC45A2. Further, in silico mutagenesis and dynamic simulation approaches revealed that a novel Cys276Arg variant abolished the cysteine bridge and might contribute toward decreased stability of the TYR protein. Our study expands the mutation spectrum of the TYR and SLC45A2 genes and emphasizes that molecular investigations are essential for accurate disease diagnosis.
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Affiliation(s)
- Nousheen Bibi
- Department of Bioinformatics, Shaheed Benazir Bhutto Women University, Peshawar, Pakistan
| | - Asmat Ullah
- Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan.,Department of Molecular Biology, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Lubna Darwesh
- Department of Biochemistry, Hazara University, Mansehra, Pakistan
| | - Waqas Khan
- Department of Biochemistry, Hazara University, Mansehra, Pakistan
| | - Tanzeela Khan
- Department of Bioinformatics, Shaheed Benazir Bhutto Women University, Peshawar, Pakistan
| | - Kalim Ullah
- Department of Zoology, Kohat University of Science and Technology, Kohat, Pakistan
| | - Bushra Khan
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Wasim Ahmad
- Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan
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Alzahrani FA, Ahmed F, Sharma M, Rehan M, Mahfuz M, Baeshen MN, Hawsawi Y, Almatrafi A, Alsagaby SA, Kamal MA, Warsi MK, Choudhry H, Jamal MS. Investigating the pathogenic SNPs in BLM helicase and their biological consequences by computational approach. Sci Rep 2020; 10:12377. [PMID: 32704157 PMCID: PMC7378827 DOI: 10.1038/s41598-020-69033-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/06/2020] [Indexed: 12/15/2022] Open
Abstract
The BLM helicase protein plays a vital role in DNA replication and the maintenance of genomic integrity. Variation in the BLM helicase gene resulted in defects in the DNA repair mechanism and was reported to be associated with Bloom syndrome (BS) and cancer. Despite extensive investigation of helicase proteins in humans, no attempt has previously been made to comprehensively analyse the single nucleotide polymorphism (SNPs) of the BLM gene. In this study, a comprehensive analysis of SNPs on the BLM gene was performed to identify, characterize and validate the pathogenic SNPs using computational approaches. We obtained SNP data from the dbSNP database version 150 and mapped these data to the genomic coordinates of the "NM_000057.3" transcript expressing BLM helicase (P54132). There were 607 SNPs mapped to missense, 29 SNPs mapped to nonsense, and 19 SNPs mapped to 3'-UTR regions. Initially, we used many consensus tools of SIFT, PROVEAN, Condel, and PolyPhen-2, which together increased the accuracy of prediction and identified 18 highly pathogenic non-synonymous SNPs (nsSNPs) out of 607 SNPs. Subsequently, these 18 high-confidence pathogenic nsSNPs were analysed for BLM protein stability, structure-function relationships and disease associations using various bioinformatics tools. These 18 mutants of the BLM protein along with the native protein were further investigated using molecular dynamics simulations to examine the structural consequences of the mutations, which might reveal their malfunction and contribution to disease. In addition, 28 SNPs were predicted as "stop gained" nonsense SNPs and one SNP was predicted as "start lost". Two SNPs in the 3'UTR were found to abolish miRNA binding and thus may enhance the expression of BLM. Interestingly, we found that BLM mRNA overexpression is associated with different types of cancers. Further investigation showed that the dysregulation of BLM is associated with poor overall survival (OS) for lung and gastric cancer patients and hence led to the conclusion that BLM has the potential to be used as an important prognostic marker for the detection of lung and gastric cancer.
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Affiliation(s)
- Faisal A Alzahrani
- Department of Biochemistry, Faculty of Science, Stem Cells Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK
| | - Firoz Ahmed
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, 21589, Saudi Arabia.
- University of Jeddah Centre for Scientific and Medical Research (UJ-CSMR), University of Jeddah, Jeddah, 21589, Saudi Arabia.
| | - Monika Sharma
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, India
| | - Mohd Rehan
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Maryam Mahfuz
- Department of Computer Science, Jamia Millia Islamia, New Delhi, Delhi, India
| | - Mohammed N Baeshen
- Department of Biology, College of Science, University of Jeddah, Jeddah, 21589, Saudi Arabia
| | - Yousef Hawsawi
- Department of Genetics, Research Center, King Faisal Specialist Hospital, and Research Center, MBC-03, PO Box 3354, Riyadh, 11211, Saudi Arabia
| | - Ahmed Almatrafi
- Department of Biology, Faculty of Science, University of Taibah, Medinah, Saudi Arabia
| | - Suliman Abdallah Alsagaby
- Department of Medical Laboratories, Central Biosciences Research Laboratories, College of Science in Al Zulfi, Majmaah University, Al Majma'ah, Saudi Arabia
| | - Mohammad Azhar Kamal
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, 21589, Saudi Arabia
- University of Jeddah Centre for Scientific and Medical Research (UJ-CSMR), University of Jeddah, Jeddah, 21589, Saudi Arabia
| | - Mohiuddin Khan Warsi
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, 21589, Saudi Arabia
- University of Jeddah Centre for Scientific and Medical Research (UJ-CSMR), University of Jeddah, Jeddah, 21589, Saudi Arabia
| | - Hani Choudhry
- Department of Biochemistry, Cancer Metabolism and Epigenetic Unit, Faculty of Science, Cancer and Mutagenesis Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammad Sarwar Jamal
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.
- Integrative Biosciences Center, Wayne State University, Detroit, MI, 48202, USA.
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33
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Koga A, Hisakawa C, Yoshizawa M. Baboon bearing resemblance in pigmentation pattern to Siamese cat carries a missense mutation in the tyrosinase gene. Genome 2020; 63:275-279. [DOI: 10.1139/gen-2020-0003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
An infant hamadryas baboon exhibiting an albino phenotype—white body hair and red eyes—was born to parents with wild-type body color. Pigmentation on some parts of its body surfaced during childhood and progressed with age. This baboon in adulthood has gray hair on parts of its body, such as the tail, distal portion of the legs, and face, with the remainder being white. This pigmentation pattern resembles that of the Siamese cat and the Himalayan variants of the mouse and the mink. The distinguishing phenotypes in these animals are known to be caused by a temperature-sensitive activity of tyrosinase, an enzyme essential for biosynthesis of melanin. We sequenced all the five exons of the tyrosinase (TYR) gene of this albino baboon, which were amplified by PCR, and found a base substitution leading to alteration of the 365th amino acid from Ala to Thr. Tyrosinase requires copper as a cofactor for its enzyme function. It has two copper-binding sites, the second of which contains His residues in positions 363 and 367 that are critical to its function. Thus, p.(Ala365Thr) due to a mutation in the TYR gene is a likely candidate for the cause of the albino phenotype in this baboon.
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Affiliation(s)
- Akihiko Koga
- Primate Research Institute, Kyoto University, Inuyama City 484-8506, Japan
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34
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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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35
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Schroeder WL, Harris SD, Saha R. Computation-Driven Analysis of Model Polyextremo-tolerant Fungus Exophiala dermatitidis: Defensive Pigment Metabolic Costs and Human Applications. iScience 2020; 23:100980. [PMID: 32240950 PMCID: PMC7115120 DOI: 10.1016/j.isci.2020.100980] [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: 01/21/2020] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 02/06/2023] Open
Abstract
The polyextremotolerant black yeast Exophiala dermatitidis is a tractable model system for investigation of adaptations that support growth under extreme conditions. Foremost among these adaptations are melanogenesis and carotenogenesis. A particularly important question is their metabolic production cost. However, investigation of this issue has been hindered by a relatively poor systems-level understanding of E. dermatitidis metabolism. To address this challenge, a genome-scale model (iEde2091) was developed. Using iEde2091, carotenoids were found to be more expensive to produce than melanins. Given their overlapping protective functions, this suggests that carotenoids have an underexplored yet important role in photo-protection. Furthermore, multiple defensive pigments with overlapping functions might allow E. dermatitidis to minimize cost. Because iEde2091 revealed that E. dermatitidis synthesizes the same melanins as humans and the active sites of the key tyrosinase enzyme are highly conserved this model may enable a broader understanding of melanin production across kingdoms.
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Affiliation(s)
- Wheaton L Schroeder
- Department of Chemical and Biomolecular Engineering, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | - Steven D Harris
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Rajib Saha
- Department of Chemical and Biomolecular Engineering, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
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36
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Matsumoto H, Kojya M, Takamuku H, Kimura S, Kashimura A, Imai S, Yamauchi K, Ito S. MC1R c.310G>- and c.871G > A determine the coat color of Kumamoto sub-breed of Japanese Brown cattle. Anim Sci J 2020; 91:e13367. [PMID: 32285552 DOI: 10.1111/asj.13367] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/11/2020] [Accepted: 03/15/2020] [Indexed: 11/28/2022]
Abstract
Coat color is one of the important factors characterizing breeds for domestic animals. Melanocortin 1 receptor (MC1R) is a representative responsible gene for this phenotype. Two single-nucleotide polymorphisms (SNPs) in bovine MC1R gene, c.296T > C and c.310G>-, have been well characterized, but these SNPs are not enough to explain cattle coat color. As far as we know, MC1R genotypes of Kumamoto sub-breed of Japanese Brown cattle have not been analyzed. In the current study, genotyping for c.296T > C and c.310G>- was performed to elucidate the role of MC1R in determining the coat color of this sub-breed. As a result, most animals were e/e genotype, suggesting the coat color of this sub-breed is derived from the e allele of MC1R gene. However, we found six animals with E/e genotype, which coat color would be black theoretically. Subsequently, sequence comparison was performed with these animals to identify other polymorphisms affecting coat color, elucidating that these animals possessed the A allele of c.871G > A commonly. c.871G > A was a non-synonymous mutation in the seventh transmembrane domain, suggesting alteration of the function and/or the structure of MC1R protein. Our data indicated that the A allele of c.871G > A might be a loss-of-function mutation.
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Affiliation(s)
- Hirokazu Matsumoto
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto, Japan
| | - Masatake Kojya
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto, Japan
| | - Hiroko Takamuku
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto, Japan
| | - Satoshi Kimura
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto, Japan
| | - Atsushi Kashimura
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto, Japan
| | - Saki Imai
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto, Japan
| | - Kenji Yamauchi
- Kumamoto Station, National Livestock Breeding Center, Kumamoto, Japan
| | - Shuichi Ito
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto, Japan
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37
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Li H, Li J, Hu Q. Ultra-Widefield Laser Scanning Retina Imaging in Oculocutaneous Albinism. JAMA Ophthalmol 2020; 138:e190399. [PMID: 32053175 DOI: 10.1001/jamaophthalmol.2019.0399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Haoyu Li
- Guangxi University of Chinese Medicine, Nanning, Guangxi, China
| | - Jianqiang Li
- Jingliang Eye Hospital, Guangxi Medical University, Nanning, Guangxi, China
| | - Qiuming Hu
- Jingliang Eye Hospital, Guangxi Medical University, Nanning, Guangxi, China
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38
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Cells to Surgery Quiz: November 2019. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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39
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Albinism: epidemiology, genetics, cutaneous characterization, psychosocial factors. An Bras Dermatol 2019; 94:503-520. [PMID: 31777350 PMCID: PMC6857599 DOI: 10.1016/j.abd.2019.09.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 09/09/2019] [Indexed: 11/20/2022] Open
Abstract
Oculocutaneous albinism is an autosomal recessive disease caused by the complete absence or decrease of melanin biosynthesis in melanocytes. Due to the reduction or absence of melanin, albinos are highly susceptible to the harmful effects of ultraviolet radiation and are at increased risk of actinic damage and skin cancer. In Brazil, as in other parts of the world, albinism remains a little known disorder, both in relation to epidemiological data and to phenotypic and genotypic variation. In several regions of the country, individuals with albinism have no access to resources or specialized medical care, and are often neglected and deprived of social inclusion. Brazil is a tropical country, with a high incidence of solar radiation during the year nationwide. Consequently, actinic damage and skin cancer occur early and have a high incidence in this population, often leading to premature death. Skin monitoring of these patients and immediate therapeutic interventions have a positive impact in reducing the morbidity and mortality associated with this condition. Health education is important to inform albinos and their families, the general population, educators, medical professionals, and public agencies about the particularities of this genetic condition. The aim of this article is to present a review of the epidemiological, clinical, genetic, and psychosocial characteristics of albinism, with a focus in skin changes caused by this rare pigmentation disorder.
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40
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Brown AE, Qiu CC, Drozd B, Sklover LR, Vickers CM, Hsu S. The color of skin: white diseases of the skin, nails, and mucosa. Clin Dermatol 2019; 37:561-579. [PMID: 31896410 DOI: 10.1016/j.clindermatol.2019.07.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
White diseases are a heterogenous group characterized by hypopigmentation or depigmentation. Skin and eye color are determined by the number and size of melanosomes present. Melanin is produced by melanosomes in the melanocytes present within the epidermis of the skin, uvea, and retinal pigmented epithelium (RPE). Conditions altering the number of melanocytes or concentration of melanin result in a lack of pigmentation, appearing as "white diseases" ranging from the well-known albinism and vitiligo to more esoteric white hand syndrome and Degos disease.
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Affiliation(s)
- Ashley E Brown
- McGovern Medical School, University of Texas Health Science Center at Houston,Houston, Texas, USA.
| | - Connie C Qiu
- Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Brandy Drozd
- McGovern Medical School, University of Texas Health Science Center at Houston,Houston, Texas, USA
| | - Lindsay R Sklover
- Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Conor M Vickers
- Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Sylvia Hsu
- Department of Dermatology, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania, USA
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41
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Abstract
Albinism can be divided into oculocutaneous albinism (OCA) and ocular albinism (OA). In the differential diagnostics these can be distinguished from rarer syndromes with partial albinism, which are frequently associated with susceptibility to infections and neurological symptoms. The OCA is an autosomal recessive inherited disease of melanin biosynthesis, which leads to complete or partial loss of melanin in the skin, hair follicles and eyes. Of the seven currently known subtypes (OCA 1-7), four are well-characterized (OCA 1-4). These are based on gene mutations, which code for tyrosinase, a key enzyme in melanin synthesis and for further proteins. These play an important role in the catalytic activity of tyrosinase and the structure and function of melanosomes. In the presence of these subtypes, the clinical symptoms and the course of the disease show a pronounced variability, especially in the type and extent of pigmentation of the skin and hair as well as the severity of eye involvement, which makes the phenotypic classification difficult. Treatment priorities are a consistent protection from UV light for prophylaxis against skin cancer and regular preventive investigations. The ocular alterations typical for albinism necessitate timely diagnostics and care by institutions specialized in ophthalmology. Novel strategies for systemic treatment of subtypes of albinism are in preclinical testing. The OA without skin involvement shows X‑linked inheritance, is much rarer and is characterized by reduced pigmentation of the retina and iris, nystagmus and macular hypoplasia, sometimes with substantial loss of visual acuity. The typical ocular symptoms of OA can be manifested to a varying extent in all forms of OCA.
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Affiliation(s)
- A S Kubasch
- UniversitätsCentrum für Seltene Erkrankungen, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Deutschland
| | - M Meurer
- Stiftung Hochschulmedizin Dresden, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Deutschland.
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42
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Luo D, Linpeng S, Zeng L, Tan H, Li Z, Wu L. Molecular genetic study of 59 Chinese Oculocutaneous albinism families. Eur J Med Genet 2019; 62:103709. [PMID: 31229681 DOI: 10.1016/j.ejmg.2019.103709] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 04/24/2019] [Accepted: 06/19/2019] [Indexed: 12/11/2022]
Abstract
Oculocutaneous albinism is an autosomal recessive disorder characterized by either a complete lack of or reduction in melanin biosynthesis in the skin, hair, and eyes. The aim of the present study was to identify the molecular basis for 59 Chinese OCA families. In this study, compound heterozygous or homozygous pathogenic variants were found in 53 families, 4 families possessed only one heterozygous variant, and the pathogenic variants of 2 families remain undiscovered by using Sanger sequencing, whole exome sequencing and multiplex ligation-dependent probe amplification. We have identified a total of 55 variants including 21 novel variants in TYR, OCA2, SLC45A2, SLC24A5, and HPS1. The 21 novel variants include 11 missense changes, 4 nonsense changes, 2 splice site changes, 1 frameshift and 3 gross deletions. Forty-six variants including 14 novel variants were segregated with the phenotype in 37 families. We conducted RT-PCR of the novel splicing site variant (c.399-14G > A) of HPS1 and verified that the variant would result in the inclusion of 12 bp of intronic material in exon 6 of HPS1. The results of platelet whole mount electron microscopy further confirmed the diagnosis of HPS1. These novel variants identified in our study expand the mutational spectrum of the disease, which contributes to prenatal diagnosis and genetic counselling.
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Affiliation(s)
- Dan Luo
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Siyuan Linpeng
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Lanlan Zeng
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Hu Tan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Zhuo Li
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Lingqian Wu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.
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43
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Lin Y, Chen X, Yang Y, Che F, Zhang S, Yuan L, Wu Y. Mutational Analysis of TYR, OCA2, and SLC45A2 Genes in Chinese Families with Oculocutaneous Albinism. Mol Genet Genomic Med 2019; 7:e00687. [PMID: 31199599 PMCID: PMC6625147 DOI: 10.1002/mgg3.687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 02/24/2019] [Accepted: 03/06/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a group of heterogeneous autosomal recessive genetic disorder of melanin synthesis results in hypopigmented hair, skin, and eyes. OCA type 1, OCA type 2, and OCA type 4, which are respectively caused by mutations in TYR, OCA2, and SLC45A2 have high morbidity rates in Asia. METHODS TYR, OCA2, and SLC45A2 mutation analysis was carried out on 18 nonconsanguineous OCA patients and four fetuses were included for prenatal diagnose. Three genes of all individuals were amplified by polymerase chain reaction and examined by Sanger sequencing. The pathogenicity of the detected mutations were analyzed by Mutation Taster, PolyPhen 2, and SIFT software, and the conservation of the substituted amino acids were analyzed by MEGA software. RESULTS Eleven TYR mutations, three OCA2 mutations, and two SLC45A2 mutations were identified in 14 OCA type 1 patients, two OCA type 2 patients, and two OCA type 4 patients. c.1021A>G, p.R341G in TYR, c.1096_1104del, p.V366*, and c.1079C>T, p.S360F in OCA2 were novel. One of the four fetuses carried compound heterozygous mutation of TYR and became spontaneous abortion, the other three carried no mutations and appeared normal at birth. CONCLUSION In this study, specific clinical characteristics of OCA patients were described. Three novel pathogenic mutations were identified which will enrich the mutation spectrum of OCA, and the prenatal genetic screening in fetus at risk of OCA can provide vital information for genetic counseling.
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Affiliation(s)
- Ye Lin
- The General Hospital of the People's Liberation Army, Beijing, P.R. China
| | - Xihui Chen
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China
| | - Ying Yang
- Shaanxi Institute of Pediatric Diseases, Xi'an Children's Hospital, Xi'an, Shaanxi, P.R. China
| | - Fengyu Che
- Shaanxi Institute of Pediatric Diseases, Xi'an Children's Hospital, Xi'an, Shaanxi, P.R. China
| | - Sijia Zhang
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China
| | - Lijuan Yuan
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China.,Department of General Surgery, Tangdu Hospital, Air Force Medical University, Xi'an, Shaanxi, P.R. China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China
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44
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Henriques LD, Oliveira JCP, Bonci DMO, Leão RC, Souza GS, Silveira LCL, Galvão OF, Goulart PRK, Ventura DF. Behavioral and genetic color vision evaluation of an albino male capuchin monkey (Sapajus apella). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:529-536. [PMID: 31111183 DOI: 10.1007/s00359-019-01342-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 04/26/2019] [Accepted: 05/04/2019] [Indexed: 11/28/2022]
Abstract
Albinism is a rare phenotype that affects the pigmentation in eyes, hair, and skin. The effects of albinism in color vision are still unclear. Our study aimed to evaluate the color vision phenotype and genotype of an albino capuchin monkey. An adult albino male capuchin monkey (Sapajus apella) had the L and M opsin gene analyzed, and was trained in a behavioral task of color discrimination. Color discrimination thresholds were determined along 20 chromatic axes around the background chromaticity. A color discrimination ellipse was drawn by interpolation among these thresholds. The albino monkey's behavioral color discrimination ellipse showed poor discrimination along the red-green axis indicating a deutan phenotype. Genetic analysis revealed only the presence of the L gene in the albino monkey. This result did not differ from that obtained with ten previously tested non-albino monkeys. Behavioral and molecular analyses agreed that the albino capuchin monkey had color vision similar to that of non-albino dichromat monkeys, suggesting no influence of albinism on color discrimination.
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Affiliation(s)
- Leonardo Dutra Henriques
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Avenida Prof. Mello Moraes 1721, São Paulo, São Paulo, CEP 05508-030, Brazil.
| | - J C P Oliveira
- Núcleo de Teoria e Pesquisa do Comportamento, Universidade Federal do Pará, Belém, Pará, Brazil
| | - D M O Bonci
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Avenida Prof. Mello Moraes 1721, São Paulo, São Paulo, CEP 05508-030, Brazil
| | - R C Leão
- Núcleo de Medicina Tropical, Universidade Federal Do Pará, Belém, Pará, Brazil.,Instituto de Ciências Biológicas, Universidade Federal Do Pará, Belém, Pará, Brazil
| | - G S Souza
- Núcleo de Medicina Tropical, Universidade Federal Do Pará, Belém, Pará, Brazil.,Instituto de Ciências Biológicas, Universidade Federal Do Pará, Belém, Pará, Brazil
| | - L C L Silveira
- Núcleo de Medicina Tropical, Universidade Federal Do Pará, Belém, Pará, Brazil.,Instituto de Ciências Biológicas, Universidade Federal Do Pará, Belém, Pará, Brazil
| | - O F Galvão
- Núcleo de Teoria e Pesquisa do Comportamento, Universidade Federal do Pará, Belém, Pará, Brazil
| | - P R K Goulart
- Núcleo de Teoria e Pesquisa do Comportamento, Universidade Federal do Pará, Belém, Pará, Brazil
| | - D F Ventura
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Avenida Prof. Mello Moraes 1721, São Paulo, São Paulo, CEP 05508-030, Brazil.,Instituto de Ensino e Pesquisa, Hospital Israelita Albert Einstein, São Paulo, São Paulo, Brazil
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Correlation between electroretinography, foveal anatomy and visual acuity in albinism. Doc Ophthalmol 2019; 139:21-32. [PMID: 30927186 DOI: 10.1007/s10633-019-09692-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 03/21/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Albinism patients have poor visual acuity in addition to hypopigmentation. Their foveal anatomy is abnormal, but correlation with function is incompletely understood. This study correlates retinal electrophysiology, visual acuity and optical coherence tomography (OCT) anatomy in albinism patients and compares with age-similar controls. METHODS Institutional Review Board approval was obtained (IRB# 201408782). Patients were recruited from clinical practice. Inclusion criteria were at least three clinical features of albinism including iris transillumination, nystagmus, fundus hypopigmentation, or foveal hypoplasia on OCT and/or molecular genetic confirmation. Diagnosys (Lowell, Mass) full-field ERG (ffERG) and VERIS multifocal ERG (mfERG; Electro-Diagnostic Imaging, Milpitas, California) were obtained using standard International Society for Clinical Electrophysiology of Vision protocols. The mfERG protocol was a 4-min 103-hexagon protocol covering approximately 40° in diameter of central retina. Control subjects without albinism were recruited by in-hospital notices and invitations in clinic. OCT central thickness was recorded, and an OCT foveal score was calculated. Nonparametric permutation testing was utilized to determine the statistical significance. RESULTS A total of 16 albinism patients and 19 age-similar controls were recruited. Four of 16 albinism patients had no nystagmus. Seventeen non-albinism controls had no ocular disorder other than refractive error. Two controls had infantile nystagmus with normal maculas on OCT. There was no statistically significant difference in mfERG amplitude or latency between albinism patients with or without nystagmus (lowest p = 0.68; 0.54, respectively). mfERG: 12 of 16 (75%) albinism patients had average ring 1 amplitudes within one standard deviation of controls despite having abnormal foveal anatomy on OCT. Patients averaged shorter latencies in rings 1 and 2 than controls (p = 0.005, p = 0.02). Patients averaged higher amplitudes than controls in rings 4, 5 and 6 (p = 0.03, p = 0.006, p = 0.004). There was no significant correlation between visual acuity and mfERG amplitudes in any ring (smallest p = 0.15). ffERG: Patients averaged higher amplitudes on 30 Hz flicker (p = 0.008). In all conditions, albinism patients had higher amplitude a-waves (p ≤ 0.03). B-waves were higher amplitude than controls in light-adapted 3.0 (p = 0.03). There was no statistical correlation between ffERG amplitudes and visual acuity (smallest p = 0.45). OCT: In albinism patients, thicker central macula on OCT correlated with lower mfERG amplitudes in all rings except for ring 1 (p < 0.05) and lower ffERG a-wave amplitudes on dark-adapted 0.01 (p = 0.003). Macular thickness on OCT did not correlate with visual acuity (p = 0.51); OCT foveal score did (p = 0.0004). CONCLUSIONS Amplitude of mfERG does not correlate with visual acuity in any ring in patients with albinism. The slope of the change in amplitude from central to peripheral rings on the mferg is significantly different in albinism patients versus controls whether or not nystagmus is present. The decreased slope of change in amplitudes from center to periphery of the macula in albinism patients indicates changes in macular topography that are more important to visual deficits than the foveal depression.
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Ather S, Proudlock FA, Welton T, Morgan PS, Sheth V, Gottlob I, Dineen RA. Aberrant visual pathway development in albinism: From retina to cortex. Hum Brain Mapp 2019; 40:777-788. [PMID: 30511784 PMCID: PMC6865554 DOI: 10.1002/hbm.24411] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 09/08/2018] [Accepted: 09/18/2018] [Indexed: 12/27/2022] Open
Abstract
Albinism refers to a group of genetic abnormalities in melanogenesis that are associated neuronal misrouting through the optic chiasm. We perform quantitative assessment of visual pathway structure and function in 23 persons with albinism (PWA) and 20 matched controls using optical coherence tomography (OCT), volumetric magnetic resonance imaging (MRI), diffusion tensor imaging and visual evoked potentials (VEP). PWA had a higher streamline decussation index (percentage of total tractography streamlines decussating at the chiasm) compared with controls (Z = -2.24, p = .025), and streamline decussation index correlated weakly with inter-hemispheric asymmetry measured using VEP (r = .484, p = .042). For PWA, a significant correlation was found between foveal development index and total number of streamlines (r = .662, p < .001). Significant positive correlations were found between peri-papillary retinal nerve fibre layer thickness and optic nerve (r = .642, p < .001) and tract (r = .663, p < .001) width. Occipital pole cortical thickness was 6.88% higher (Z = -4.10, p < .001) in PWA and was related to anterior visual pathway structures including foveal retinal pigment epithelium complex thickness (r = -.579, p = .005), optic disc (r = .478, p = .021) and rim areas (r = .597, p = .003). We were unable to demonstrate a significant relationship between OCT-derived foveal or optic nerve measures and MRI-derived chiasm size or streamline decussation index. Our novel tractographic demonstration of altered chiasmatic decussation in PWA corresponds to VEP measured cortical asymmetry and is consistent with chiasmatic misrouting in albinism. We also demonstrate a significant relationship between retinal pigment epithelium and visual cortex thickness indicating that retinal pigmentation defects in albinism lead to downstream structural reorganisation of the visual cortex.
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Affiliation(s)
- Sarim Ather
- Nuffield Department of Surgical SciencesUniversity of OxfordOxfordUnited Kingdom
| | - Frank Anthony Proudlock
- University of Leicester Ulverscroft Eye UnitRobert Kilpatrick Clinical Sciences BuildingLeicesterUnited Kingdom
| | - Thomas Welton
- Radiological Sciences, Division of Clinical NeuroscienceUniversity of Nottingham, Queen's Medical CentreNottinghamUnited Kingdom
- Sir Peter Mansfield Imaging Centre, University of NottinghamQueen's Medical CentreNottinghamUnited Kingdom
| | - Paul S. Morgan
- Sir Peter Mansfield Imaging Centre, University of NottinghamQueen's Medical CentreNottinghamUnited Kingdom
- Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS TrustQueen's Medical CentreNottinghamUnited Kingdom
| | - Viral Sheth
- University of Leicester Ulverscroft Eye UnitRobert Kilpatrick Clinical Sciences BuildingLeicesterUnited Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye UnitRobert Kilpatrick Clinical Sciences BuildingLeicesterUnited Kingdom
| | - Rob A. Dineen
- Radiological Sciences, Division of Clinical NeuroscienceUniversity of Nottingham, Queen's Medical CentreNottinghamUnited Kingdom
- Sir Peter Mansfield Imaging Centre, University of NottinghamQueen's Medical CentreNottinghamUnited Kingdom
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Adams DR, Menezes S, Jauregui R, Valivullah ZM, Power B, Abraham M, Jeffrey BG, Garced A, Alur RP, Cunningham D, Wiggs E, Merideth MA, Chiang PW, Bernstein S, Ito S, Wakamatsu K, Jack RM, Introne WJ, Gahl WA, Brooks BP. One-year pilot study on the effects of nitisinone on melanin in patients with OCA-1B. JCI Insight 2019; 4:124387. [PMID: 30674731 PMCID: PMC6413781 DOI: 10.1172/jci.insight.124387] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/06/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND. Oculocutaneous albinism (OCA) results in reduced melanin synthesis, skin hypopigmentation, increased risk of UV-induced malignancy, and developmental eye abnormalities affecting vision. No treatments exist. We have shown that oral nitisinone increases ocular and fur pigmentation in a mouse model of one form of albinism, OCA-1B, due to hypomorphic mutations in the Tyrosinase gene. METHODS. In this open-label pilot study, 5 adult patients with OCA-1B established baseline measurements of iris, skin, and hair pigmentation and were treated over 12 months with 2 mg/d oral nitisinone. Changes in pigmentation and visual function were evaluated at 3-month intervals. RESULTS. The mean change in iris transillumination, a marker of melanin, from baseline was 1.0 ± 1.54 points, representing no change. The method of iris transillumination grading showed a high intergrader reliability (intraclass correlation coefficient ≥ 0.88 at each visit). The number of letters read (visual acuity) improved significantly at month 12 for both eyes (right eye, OD, mean 4.2 [95% CI, 0.3, 8.1], P = 0.04) and left eye (OS, 5 [1.0, 9.1], P = 0.003). Skin pigmentation on the inner bicep increased (M index increase = 1.72 [0.03, 3.41], P = 0.047). Finally, hair pigmentation increased by both reflectometry (M index [17.3 {4.4, 30.2}, P = 0.01]) and biochemically. CONCLUSION. Nitisinone did not result in an increase in iris melanin content but may increase hair and skin pigmentation in patients with OCA-1B. The iris transillumination grading scale used in this study proved robust, with potential for use in future clinical trials. TRIAL REGISTRATION. ClinicalTrials.gov NCT01838655. FUNDING. Intramural program of the National Eye Institute. Oral nitisinone may improve melanin pigmentation in patients with the OCA-1B form of albinism due to hypomorphic mutations in the tyrosinase gene.
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Affiliation(s)
- David R Adams
- National Human Genome Research Institute, NIH, Department of Health and Human Services, Bethesda, Maryland, USA
| | | | | | - Zaheer M Valivullah
- National Human Genome Research Institute, NIH, Department of Health and Human Services, Bethesda, Maryland, USA
| | - Bradley Power
- National Human Genome Research Institute, NIH, Department of Health and Human Services, Bethesda, Maryland, USA
| | | | | | | | | | | | - Edythe Wiggs
- National Institute of Neurological Disease and Stroke, NIH, Department of Health and Human Services, Bethesda, Maryland, USA
| | - Melissa A Merideth
- National Human Genome Research Institute, NIH, Department of Health and Human Services, Bethesda, Maryland, USA
| | | | - Shanna Bernstein
- Nutrition Department, NIH Clinical Center, Bethesda, Maryland, USA
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan
| | - Rhona M Jack
- Seattle Children's Hospital, Department of Pathology & Laboratory Medicine, Seattle, Washington, USA
| | - Wendy J Introne
- National Human Genome Research Institute, NIH, Department of Health and Human Services, Bethesda, Maryland, USA
| | - William A Gahl
- National Human Genome Research Institute, NIH, Department of Health and Human Services, Bethesda, Maryland, USA
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de Gennaro G, Vitti P, Marinò M. A Case of Oculocutaneous Albinism in a Patient with Hashimoto's Thyroiditis. Eur Thyroid J 2019; 8:56-58. [PMID: 30800642 PMCID: PMC6381916 DOI: 10.1159/000493730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/13/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a heterogeneous autosomal recessive disorder characterized by reduced or absent melanin synthesis. Its prevalence is approximately one in 17,000 individuals worldwide. OCA causes a complete or partial absence of pigment in the skin, hair, and eyes. Reduction of melanin in the eyes results in reduced visual acuity, photophobia, and nystagmus. To our knowledge, the coexistence of albinism and thyroid autoimmune diseases has not been reported. CASE REPORT A 37-year-old male with OCA came to our observation for a familial history of autoimmune thyroiditis. He complained with mild asthenia. His brother was affected by OCA and autoimmune thyroiditis. Physical examination revealed the presence of fair skin, platinum white hair, and hypopigmentation of the iris. Laboratory data revealed the presence of subclinical hypothyroidism with positive serum anti-thyroid antibodies. Neck ultrasonography showed a markedly heterogeneously hypoechoic pattern of the thyroid, with a honeycomb-like appearance. DISCUSSION In the majority of cases, OCA in Caucasians is caused by mutations in the tyrosinase gene. The tyrosinase peptide is normally expressed on the surface of melanocytes, although recent studies have shown its presence in thyroid follicular epithelial cells of patients with Hashimoto's thyroiditis. Therefore, although the mechanism is unclear, the present case report may suggest a pathogenetic link between OCA and Hashimoto's thyroiditis.
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Affiliation(s)
| | | | - Michele Marinò
- *Michele Marinò, Department of Clinical and Experimental Medicine, Endocrinology Unit I, University of Pisa and University Hospital of Pisa, Via Paradisa 2, IT–56124 Pisa (Italy), E-Mail
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On the origin of proteins in human drusen: The meet, greet and stick hypothesis. Prog Retin Eye Res 2018; 70:55-84. [PMID: 30572124 DOI: 10.1016/j.preteyeres.2018.12.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/12/2022]
Abstract
Retinal drusen formation is not only a clinical hallmark for the development of age-related macular degeneration (AMD) but also for other disorders, such as Alzheimer's disease and renal diseases. The initiation and growth of drusen is poorly understood. Attention has focused on lipids and minerals, but relatively little is known about the origin of drusen-associated proteins and how they are retained in the space between the basal lamina of the retinal pigment epithelium and the inner collagenous layer space (sub-RPE-BL space). While some authors suggested that drusen proteins are mainly derived from cellular debris from processed photoreceptor outer segments and the RPE, others suggest a choroidal cell or blood origin. Here, we reviewed and supplemented the existing literature on the molecular composition of the retina/choroid complex, to gain a more complete understanding of the sources of proteins in drusen. These "drusenomics" studies showed that a considerable proportion of currently identified drusen proteins is uniquely originating from the blood. A smaller, but still large fraction of drusen proteins comes from both blood and/or RPE. Only a small proportion of drusen proteins is uniquely derived from the photoreceptors or choroid. We next evaluated how drusen components may "meet, greet and stick" to each other and/or to structures like hydroxyapatite spherules to form macroscopic deposits in the sub-RPE-BL space. Finally, we discuss implications of our findings with respect to the previously proposed homology between drusenogenesis in AMD and plaque formation in atherosclerosis.
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Kumar R, Bansal A, Shukla R, Raj Singh T, Wasudeo Ramteke P, Singh S, Gautam B. In silico screening of deleterious single nucleotide polymorphisms (SNPs) and molecular dynamics simulation of disease associated mutations in gene responsible for oculocutaneous albinism type 6 (OCA 6) disorder. J Biomol Struct Dyn 2018; 37:3513-3523. [PMID: 30204049 DOI: 10.1080/07391102.2018.1520649] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Solute carrier family 24 member 5 (SLC24A5) is a gene that is associated with oculocutaneous albinism type 6 (OCA6) disorder and is involved in skin and hair pigmentation. It is involved in the maturation of melanosomes and melanin synthesis. SLC24A5 gene is located in the chromosomal position of 15q21.1. The present study involves the use of computational techniques in order to obtain a detailed picture of the most probable mutations that are associated with SLC24A5. From the observed result it was found that the mutation S145F is most deleterious and disease associated is predicted using several bioinformatics tools. The 3-D structures of native and mutant (S145F) were modeled in order to understand protein functionality using ab initio Robetta server. The modeled structure validation was done with ERRAT, Verify-3D, Procheck and RAMPAGE Ramachandran plot analysis. The most validated structure undergoes molecular dynamics simulations (MDS) study to understand the structural and functional behaviour of the native and mutant proteins. The MDS result showed the more flexibility in the native SLC24A5 structure. Due to mutation in the SLC24A5 protein structure it became more rigid and might disturb the conformational changes and glycosylation function of protein structure and might play role in inducing the OCA6. This study provides a significant insight into the underlying molecular mechanism involved in albinism associated with OCA6. It further helps scientists to develop a drug therapy against OCA 6 disease. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Rutash Kumar
- a Department of Computational Biology & Bioinformatics , Jacob Institute of Biotechnology & Bio-Engineering, Sam Higginbottom University of Agriculture, Technology and Sciences (SHUATS) , Allahabad , India
| | - Ankush Bansal
- b Department of Biotechnology and Bioinformatics , Jaypee University of Information Technology , Solan , India
| | - Rohit Shukla
- b Department of Biotechnology and Bioinformatics , Jaypee University of Information Technology , Solan , India
| | - Tiratha Raj Singh
- b Department of Biotechnology and Bioinformatics , Jaypee University of Information Technology , Solan , India
| | - Pramod Wasudeo Ramteke
- a Department of Computational Biology & Bioinformatics , Jacob Institute of Biotechnology & Bio-Engineering, Sam Higginbottom University of Agriculture, Technology and Sciences (SHUATS) , Allahabad , India
| | - Satendra Singh
- a Department of Computational Biology & Bioinformatics , Jacob Institute of Biotechnology & Bio-Engineering, Sam Higginbottom University of Agriculture, Technology and Sciences (SHUATS) , Allahabad , India
| | - Budhayash Gautam
- a Department of Computational Biology & Bioinformatics , Jacob Institute of Biotechnology & Bio-Engineering, Sam Higginbottom University of Agriculture, Technology and Sciences (SHUATS) , Allahabad , India
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