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Kohli S, Saxena R, Puri RD, Bijarnia Mahay S, Pal S, Dubey S, Arora V, Verma I. The molecular landscape of oculocutaneous albinism in India and its therapeutic implications. Eur J Hum Genet 2023:10.1038/s41431-023-01496-5. [PMID: 38030918 DOI: 10.1038/s41431-023-01496-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 10/14/2023] [Accepted: 11/08/2023] [Indexed: 12/01/2023] Open
Abstract
Oculocutaneous albinism is an inherited disorder of melanin biosynthesis, characterized by absent or reduced pigmentation of the skin, hair, and eyes. Molecular alterations of genes that cause non-syndromic albinism in Asian Indians are poorly characterized. This information would be useful for developing therapies for this disorder. We analyzed 164 persons with non-syndromic albinism, belonging to unrelated families from all parts of India, for molecular changes in the causative genes. Subjects with white hair, white skin, and red iris had their tyrosinase gene sequenced and were also tested by MLPA for deletions/duplications. Subjects with negative results or with darker skin, golden/brown or darker hair had sequencing of TYR, P, TYRP1, SLC45A2 and GPR143 genes. Pathogenic variants in TYR (OCA1) were observed in 139 (84.7%) patients, in the P gene (OCA2) in 20 (12.2%), in TYRP1 (OCA3) in two (1.2%), in SLC45A2 (OCA 4) in one (0.61%), and in GPR143 (X-linked ocular albinism) in two (1.2%) patients. Of 278 alleles with variants in TYR, 179 (64.3%) alleles had (p.R278*) alteration, suggesting the possibility of therapy with a stop codon readthrough molecule. We report 20 patients with 13 disease associated variants in the P gene and 18 novel pathogenic variants in TYR, P, TYRP1, SLC45A2 and GPR143 genes. The data are compared with those reported from India, Pakistan and rest of the world. The therapeutic options in albinism are briefly described, opening this field for future therapies.
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Affiliation(s)
- Sudha Kohli
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India.
| | - Renu Saxena
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Ratna Dua Puri
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Sunita Bijarnia Mahay
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Swasti Pal
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Sudhisha Dubey
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Veronica Arora
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Ishwar Verma
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India.
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Montijn JS, Riguccini V, Levelt CN, Heimel JA. Impaired Direction Selectivity in the Nucleus of the Optic Tract of Albino Mice. Invest Ophthalmol Vis Sci 2023; 64:9. [PMID: 37548962 PMCID: PMC10411648 DOI: 10.1167/iovs.64.11.9] [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: 05/09/2023] [Accepted: 07/17/2023] [Indexed: 08/08/2023] Open
Abstract
Purpose Human albinos have a low visual acuity. This is partially due to the presence of spontaneous erroneous eye movements called pendular nystagmus. This nystagmus is present in other albino vertebrates and has been hypothesized to be caused by aberrant wiring of retinal ganglion axons to the nucleus of the optic tract (NOT), a part of the accessory optic system involved in the optokinetic response to visual motion. The NOT in pigmented rodents is preferentially responsive to ipsiversive motion (i.e., motion in the contralateral visual field in the temporonasal direction). We compared the response to visual motion in the NOT of albino and pigmented mice to understand if motion coding and preference are impaired in the NOT of albino mice. Methods We recorded neuronal spiking activity with Neuropixels probes in the visual cortex and NOT in C57BL/6JRj mice (pigmented) and DBA/1JRj mice with oculocutaneous albinism (albino). Results We found that in pigmented mice, NOT is retinotopically organized, and neurons are direction tuned, whereas in albino mice, neuronal tuning is severely impaired. Neurons in the NOT of albino mice do not have a preference for ipsiversive movement. In contrast, neuronal tuning in visual cortex was preserved in albino mice and did not differ significantly from the tuning in pigmented mice. Conclusions We propose that excessive interhemispheric crossing of retinal projections in albinos may cause the disrupted left/right direction encoding we found in NOT. This, in turn, impairs the normal horizontal optokinetic reflex and leads to pendular albino nystagmus.
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Affiliation(s)
- Jorrit S. Montijn
- Department of Circuits, Structure & Function, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Valentina Riguccini
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Christiaan N. Levelt
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, the Netherlands
| | - J. Alexander Heimel
- Department of Circuits, Structure & Function, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
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Zhang Y, Mei Y, Cao A, Li S, He C, Song L, Gao J, Zhu Y, Cao X. Transcriptome analyses of betta fish (Betta splendens) provide novel insights into fin regeneration and color-related genes. Gene 2023:147508. [PMID: 37230203 DOI: 10.1016/j.gene.2023.147508] [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: 01/28/2023] [Revised: 04/17/2023] [Accepted: 05/22/2023] [Indexed: 05/27/2023]
Abstract
The betta fish (Betta splendens), an important ornamental fish, haswell-developed and colorful fins.After fin amputation, betta fish can easily regenerate finssimilar to the originalsin terms of structureand color. The powerful fin regeneration ability and a variety of colors in the betta fish are fascinating. However, the underlying molecular mechanisms are still not fully understood. In this study, tail fin amputation and regeneration experiments were performed on two kinds of betta fish: red and white color betta fish. Then, transcriptome analyseswere conducted to screen out fin regeneration and color-relatedgenes in betta fish. Through enrichment analyses of differentially expressed genes (DEGs), we founda series of enrichment pathways and genes related to finregeneration, including cell cycle (i.e. plcg2), TGF-beta signaling pathway (i.e. bmp6), PI3K-Akt signaling pathway (i.e. loxl2aand loxl2b), Wnt signaling pathway(i.e. lef1), gap junctions (i.e. cx43), angiogenesis (i.e. foxp1), and interferon regulatory factor (i.e. irf8). Meanwhile, some fin color-related pathways and genes were identified in betta fish, especially melanogenesis (i.e. tyr, tyrp1a, tyrp1b, and mc1r) and carotenoid color genes (i.e. pax3, pax7, sox10, and ednrba). In conclusion, this studycan not only enrich the research onfish tissue regeneration, but also has a potential significance for the aquaculture and breeding of the betta fish.
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Affiliation(s)
- Yunbang Zhang
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Hubei, People's Republic of China
| | - Yihui Mei
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
| | - Aiying Cao
- Beijing Aquaculture Technology Extention Station, Beijing 100176, China
| | - Sen Li
- Beijing Aquaculture Technology Extention Station, Beijing 100176, China
| | - Chuan He
- Beijing Aquaculture Technology Extention Station, Beijing 100176, China
| | - Liyuan Song
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
| | - Jian Gao
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Hubei, People's Republic of China
| | - Yurong Zhu
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Hubei, People's Republic of China.
| | - Xiaojuan Cao
- College of Fisheries, Engineering Research Center of Green development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Hubei, People's Republic of China.
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Puckett EE, Davis IS, Harper DC, Wakamatsu K, Battu G, Belant JL, Beyer DE, Carpenter C, Crupi AP, Davidson M, DePerno CS, Forman N, Fowler NL, Garshelis DL, Gould N, Gunther K, Haroldson M, Ito S, Kocka D, Lackey C, Leahy R, Lee-Roney C, Lewis T, Lutto A, McGowan K, Olfenbuttel C, Orlando M, Platt A, Pollard MD, Ramaker M, Reich H, Sajecki JL, Sell SK, Strules J, Thompson S, van Manen F, Whitman C, Williamson R, Winslow F, Kaelin CB, Marks MS, Barsh GS. Genetic architecture and evolution of color variation in American black bears. Curr Biol 2023; 33:86-97.e10. [PMID: 36528024 PMCID: PMC10039708 DOI: 10.1016/j.cub.2022.11.042] [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: 09/14/2022] [Revised: 11/08/2022] [Accepted: 11/18/2022] [Indexed: 12/23/2022]
Abstract
Color variation is a frequent evolutionary substrate for camouflage in small mammals, but the underlying genetics and evolutionary forces that drive color variation in natural populations of large mammals are mostly unexplained. The American black bear, Ursus americanus (U. americanus), exhibits a range of colors including the cinnamon morph, which has a similar color to the brown bear, U. arctos, and is found at high frequency in the American southwest. Reflectance and chemical melanin measurements showed little distinction between U. arctos and cinnamon U. americanus individuals. We used a genome-wide association for hair color as a quantitative trait in 151 U. americanus individuals and identified a single major locus (p < 10-13). Additional genomic and functional studies identified a missense alteration (R153C) in Tyrosinase-related protein 1 (TYRP1) that likely affects binding of the zinc cofactor, impairs protein localization, and results in decreased pigment production. Population genetic analyses and demographic modeling indicated that the R153C variant arose 9.36 kya in a southwestern population where it likely provided a selective advantage, spreading both northwards and eastwards by gene flow. A different TYRP1 allele, R114C, contributes to the characteristic brown color of U. arctos but is not fixed across the range.
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Affiliation(s)
- Emily E Puckett
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA.
| | - Isis S Davis
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Dawn C Harper
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, Japan
| | - Gopal Battu
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Jerrold L Belant
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | - Dean E Beyer
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | - Colin Carpenter
- West Virginia Division of Natural Resources, Beckley, WV 25801, USA
| | - Anthony P Crupi
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Douglas, Juneau, AK 99824, USA
| | - Maria Davidson
- The Louisiana Department of Wildlife and Fisheries, Baton Rouge, LA 70898, USA
| | - Christopher S DePerno
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695-7646, USA
| | - Nicholas Forman
- New Mexico Department of Game and Fish, Santa Fe, NM 87507, USA
| | - Nicholas L Fowler
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Douglas, Juneau, AK 99824, USA
| | - David L Garshelis
- Minnesota Department of Natural Resources, Grand Rapids, MN 55744, USA; IUCN SSC Bear Specialist Group
| | - Nicholas Gould
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695-7646, USA
| | - Kerry Gunther
- National Park Service, Yellowstone National Park, WY 82190-0168, USA
| | - Mark Haroldson
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Interagency Grizzly Bear Study Team, Bozeman, MT 59715, USA
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, Japan
| | - David Kocka
- Virginia Department of Wildlife Resources, Verona, VA 24482, USA
| | - Carl Lackey
- Nevada Department of Wildlife, Reno, NV 89512, USA
| | - Ryan Leahy
- National Park Service, Yosemite National Park Wildlife Management, Yosemite, CA 95389, USA
| | - Caitlin Lee-Roney
- National Park Service, Yosemite National Park Wildlife Management, Yosemite, CA 95389, USA
| | - Tania Lewis
- National Park Service, Glacier Bay National Park, Gustavus, AK 99826, USA
| | - Ashley Lutto
- U.S. Fish and Wildlife Service, Kenai National Wildlife Refuge, Soldotna, AK 99669, USA
| | - Kelly McGowan
- Department of Genetics, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | | | - Mike Orlando
- Florida Fish and Wildlife Conservation Commission, Tallahassee, FL 32399, USA
| | - Alexander Platt
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew D Pollard
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Megan Ramaker
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | | | - Jaime L Sajecki
- Virginia Department of Wildlife Resources, Verona, VA 24482, USA
| | - Stephanie K Sell
- Division of Wildlife Conservation, Alaska Department of Fish and Game, Douglas, Juneau, AK 99824, USA
| | - Jennifer Strules
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695-7646, USA
| | - Seth Thompson
- Virginia Department of Wildlife Resources, Verona, VA 24482, USA
| | - Frank van Manen
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Interagency Grizzly Bear Study Team, Bozeman, MT 59715, USA
| | - Craig Whitman
- U.S. Geological Survey, Northern Rocky Mountain Science Center, Interagency Grizzly Bear Study Team, Bozeman, MT 59715, USA
| | - Ryan Williamson
- National Park Service, Great Smoky Mountains National Park, Gatlinburg, TN 37738, USA
| | | | - Christopher B Kaelin
- Department of Genetics, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Departments of Pathology and Laboratory Medicine and of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gregory S Barsh
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA; Department of Genetics, School of Medicine, Stanford University, Stanford, CA 94305, USA
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5
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Dolinska MB, Anderson DE, Sergeev YV. In vitro characterization of the intramelanosomal domain of human recombinant TYRP1 and its oculocutaneous albinism type 3-related mutant variants. Protein Sci 2023; 32:e4518. [PMID: 36412553 PMCID: PMC9793978 DOI: 10.1002/pro.4518] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022]
Abstract
Tyrosinase related protein 1 (TYRP1) is the most abundant melanosomal protein of the melanocyte, where plays an important role in the synthesis of eumelanin, possibly catalyzing the oxidation of 5,6-dihydroxyindole-2-carboxylic acid to 5,6-quinone-2-carboxylic acid. Mutations to the TYRP1 gene can result in oculocutaneous albinism type 3 (OCA3), a rare disease characterized by reduced synthesis of melanin in skin, hair, and eyes. To investigate the effect of genetic mutations on the TYRP1 structure, function, and stability, we engineered the intramelanosomal domain of TYRP1 and its mutant variants mimicking either OCA3-related changes, C30R, H215Y, D308N, and R326H or R87G mutant variant, analogous to OCA1-related pathogenic effect in tyrosinase. Proteins were produced in Trichoplusia Ni larvae, then purified, and analyzed by biochemical methods. Data shows that D308N and R326H mutants keep the native conformations and demonstrate no change in their stability and enzymatic activity. In contrast, mutations C30R and R87G localized in the Cys-rich domain show the variants misfolding during the purification process. The H215Y variant disrupts the binding of Zn2+ in the active site and thus reduces the strength of the enzyme/substrate interactions. Our results, consistent with the clinical and in silico studies, show that mutations at the protein surface are expected to have a negligible phenotype change compared to that of TYRP1. For the mutations with severe phenotype changes, which were localized in the Cys-rich domain or the active site, we confirmed a complete or partial protein misfolding as the possible mechanism of protein malfunction caused by OCA3 inherited mutations.
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Affiliation(s)
| | - David E. Anderson
- National Institute of Diabetes and Digestive and Kidney DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Yuri V. Sergeev
- National Eye InstituteNational Institutes of HealthBethesdaMarylandUSA
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The retinal pigmentation pathway in human albinism: Not so black and white. Prog Retin Eye Res 2022; 91:101091. [PMID: 35729001 DOI: 10.1016/j.preteyeres.2022.101091] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 12/16/2022]
Abstract
Albinism is a pigment disorder affecting eye, skin and/or hair. Patients usually have decreased melanin in affected tissues and suffer from severe visual abnormalities, including foveal hypoplasia and chiasmal misrouting. Combining our data with those of the literature, we propose a single functional genetic retinal signalling pathway that includes all 22 currently known human albinism disease genes. We hypothesise that defects affecting the genesis or function of different intra-cellular organelles, including melanosomes, cause syndromic forms of albinism (Hermansky-Pudlak (HPS) and Chediak-Higashi syndrome (CHS)). We put forward that specific melanosome impairments cause different forms of oculocutaneous albinism (OCA1-8). Further, we incorporate GPR143 that has been implicated in ocular albinism (OA1), characterised by a phenotype limited to the eye. Finally, we include the SLC38A8-associated disorder FHONDA that causes an even more restricted "albinism-related" ocular phenotype with foveal hypoplasia and chiasmal misrouting but without pigmentation defects. We propose the following retinal pigmentation pathway, with increasingly specific genetic and cellular defects causing an increasingly specific ocular phenotype: (HPS1-11/CHS: syndromic forms of albinism)-(OCA1-8: OCA)-(GPR143: OA1)-(SLC38A8: FHONDA). Beyond disease genes involvement, we also evaluate a range of (candidate) regulatory and signalling mechanisms affecting the activity of the pathway in retinal development, retinal pigmentation and albinism. We further suggest that the proposed pigmentation pathway is also involved in other retinal disorders, such as age-related macular degeneration. The hypotheses put forward in this report provide a framework for further systematic studies in albinism and melanin pigmentation disorders.
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Ullah MI. Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review. Genes (Basel) 2022; 13:genes13061072. [PMID: 35741834 PMCID: PMC9222488 DOI: 10.3390/genes13061072] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 02/01/2023] Open
Abstract
Oculocutaneous albinism (OCA) is an autosomal recessive syndromic and non-syndromic defect with deficient or a complete lack of the melanin pigment. The characteristics of OCA appears in skin, hair, and eyes with variable degree of pigmentation. Clinical manifestations of OCA include nystagmus, photophobia, reduced visual acuity, hypo-plastic macula, and iris trans-illumination. There are eight OCA types (OCA1–8) documented with non-syndromic characteristics. Molecular studies identified seven genes linked to the OCA phenotype (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, C10orf11, and DCT) and one locus (OCA5) in consanguineous and sporadic albinism. The complications of OCA result in skin cancer and variable syndromes such as Hermansky–Pudlak syndrome (HPS) Chediak–Higashi syndrome (CHS). In the Pakistani population, autosomal recessive non-syndromic OCA is common and is associated with a large number of consanguineous families, and mutations in genes of non-syndromic types are reported. This review highlights the updates on the genetic mutation of OCA genes reported from Pakistani families. Several studies reported the genetic mutations in OCA1, OCA2, OCA3, OCA4, and OCA6 albinism in Pakistani families. A locus, OCA5, was also reported from the Pakistani population, but the gene has not been identified. A new type of OCA8 was identified due to the DCT gene mutation, and it is also reviewed here.
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Affiliation(s)
- Muhammad Ikram Ullah
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 75471, Aljouf, Saudi Arabia
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8
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Lin S, Sanchez-Bretaño A, Leslie JS, Williams KB, Lee H, Thomas NS, Callaway J, Deline J, Ratnayaka JA, Baralle D, Schmitt MA, Norman CS, Hammond S, Harlalka GV, Ennis S, Cross HE, Wenger O, Crosby AH, Baple EL, Self JE. Evidence that the Ser192Tyr/Arg402Gln in cis Tyrosinase gene haplotype is a disease-causing allele in oculocutaneous albinism type 1B (OCA1B). NPJ Genom Med 2022; 7:2. [PMID: 35027574 PMCID: PMC8758782 DOI: 10.1038/s41525-021-00275-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/19/2021] [Indexed: 01/09/2023] Open
Abstract
Oculocutaneous albinism type 1 (OCA1) is caused by pathogenic variants in the TYR (tyrosinase) gene which encodes the critical and rate-limiting enzyme in melanin synthesis. It is the most common OCA subtype found in Caucasians, accounting for ~50% of cases worldwide. The apparent 'missing heritability' in OCA is well described, with ~25-30% of clinically diagnosed individuals lacking two clearly pathogenic variants. Here we undertook empowered genetic studies in an extensive multigenerational Amish family, alongside a review of previously published literature, a retrospective analysis of in-house datasets, and tyrosinase activity studies. Together this provides irrefutable evidence of the pathogenicity of two common TYR variants, p.(Ser192Tyr) and p.(Arg402Gln) when inherited in cis alongside a pathogenic TYR variant in trans. We also show that homozygosity for the p.(Ser192Tyr)/p.(Arg402Gln) TYR haplotype results in a very mild, but fully penetrant, albinism phenotype. Together these data underscore the importance of including the TYR p.(Ser192Tyr)/p.(Arg402Gln) in cis haplotype as a pathogenic allele causative of OCA, which would likely increase molecular diagnoses in this missing heritability albinism cohort by 25-50%.
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Affiliation(s)
- Siying Lin
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
| | - Aida Sanchez-Bretaño
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Joseph S Leslie
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
| | - Katie B Williams
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - N Simon Thomas
- Faculty of Medicine, University of Southampton, Southampton, UK
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
| | - Jonathan Callaway
- Faculty of Medicine, University of Southampton, Southampton, UK
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
| | - James Deline
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Diana Baralle
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Melanie A Schmitt
- University of Wisconsin School of Medicine and Public Health, Department of Ophthalmology & Visual Sciences, Madison, WI, USA
| | - Chelsea S Norman
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- The Rosalind Franklin Institute, Rutherford Appleton Laboratories, Harwell Science and Innovation Campus, Didcot, UK
| | - Sheri Hammond
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - Gaurav V Harlalka
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
- Rajarshi Shahu College of Pharmacy, Malvihir, Buldana, India
| | - Sarah Ennis
- Department of Human Genetics and Genomic Medicine, University of Southampton, Southampton, UK
| | - Harold E Cross
- Department of Ophthalmology, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Olivia Wenger
- New Leaf Clinic, PO Box 336, 16014 East Chestnut Street, Mount Eaton, OH, 44691, USA
- Department of Pediatrics, Akron Children's Hospital, 214 West Bowery Street, Akron, OH, 44308, USA
| | - Andrew H Crosby
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK.
| | - Emma L Baple
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK.
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Gladstone Road, Exeter, UK.
| | - Jay E Self
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
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Kromberg JGR, Kerr R. Oculocutaneous albinism in southern Africa: Historical background, genetic, clinical and psychosocial issues. Afr J Disabil 2022; 11:877. [PMID: 36353393 PMCID: PMC9639357 DOI: 10.4102/ajod.v11i0.877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 05/29/2022] [Indexed: 05/09/2023] Open
Abstract
Albinism is an inherited condition associated with significant depigmentation of the skin, hair and eyes. It occurs in every population with varying frequency, and narratives of people with albinism have been recorded since 200 BC. In southern Africa albinism is common, about 1 in 4000 people are affected, but it remains a poorly understood condition surrounded by myths and superstition. This article provides a historical background on oculocutaneous albinism (OCA) in southern Africa and presents relevant information from the literature regarding epidemiology, genetics and genetic counselling, health, psychosocial and cultural issues, and medical care. There are several recessively inherited types of OCA and a mutation, responsible for about 80% of South African variants, has been identified in OCA type 2. The physical characteristics associated with albinism, that is, sun-sensitive skin and low vision, can be managed. However, people with OCA in Africa also experience psychosocial issues, such as discrimination, because of the various superstitious beliefs and attitudes held in the community. Management should include medical care for health problems, appropriate adjustment of the schooling context and genetic counseling. In addition, widespread public awareness programmes are required to increase the knowledge of the genetic causes of OCA and of the nature of genetic counselling, to address the negative attitudes in the community, to reduce the marginalisation and stigmatization of people with albinism and to improve their quality of life.
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Affiliation(s)
- Jennifer G R Kromberg
- Department of Human Genetics, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
| | - Robyn Kerr
- Department of Human Genetics, Faculty of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
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10
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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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11
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Dumitrescu AV, Tran J, Pfeifer W, Bhattarai SV, Kemerley A, Dunn TV, Wang K, Scheetz TE, Drack A. Clinical albinism score, presence of nystagmus and optic nerves defects are correlated with visual outcome in patients with oculocutaneous albinism. Ophthalmic Genet 2021; 42:539-552. [PMID: 34251969 DOI: 10.1080/13816810.2021.1933544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Purpose: To correlate clinical features, molecular genetic findings, and visual acuity in a cohort of patients clinically diagnosed with oculocutaneous albinism.Design: Retrospective chart reviewMethods: 58 charts met the inclusion criteria. Clinical examination, ancillary testing, and molecular genetic diagnoses were extracted. A novel clinical albinism score (CAS) was developed.Results: A least one likely pathogenic mutation was found in 44/58 (75.9%) patients. Mutations in the OCA1 gene were the most common (52.3%), followed by OCA2 (34%), OCA4 (2.3%), OA1 (6.8%), and HPS (4.5%). Thirty-four percentage of patients had a complete genotype, 41% had one mutation found and 24% had negative genetic testing. CAS was statistically significantly higher in patients with complete genotype, versus patients with one or no mutations found (p < .01). Better visual acuity was associated with lower CAS and fewer disease-causing mutations (p < .01). Foveal defects and iris transillumination were associated with a higher number of mutations (p < .01). Patients with nystagmus or anomalous optic nerves had worse visual acuity than those who did not (p < .01, p < .05).Conclusions: Patients with a complete genotype were more likely to have higher CAS. Vision loss correlated with complete phenotype and higher CAS, the presence of nystagmus and anomalous optic nerves. Patients with features of albinism in whom an incomplete genotype was found had better vision than those with complete genotype, suggesting a mild occult mutation or modifier variant. Genetic diagnosis is vital for complete diagnosis, counseling, and family planning.
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Affiliation(s)
- Alina V Dumitrescu
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA.,Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Johnny Tran
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Wanda Pfeifer
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Sajag V Bhattarai
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Andrew Kemerley
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Taylor V Dunn
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Kai Wang
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Tod E Scheetz
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Arlene Drack
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
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12
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Fernández A, Hayashi M, Garrido G, Montero A, Guardia A, Suzuki T, Montoliu L. Genetics of non-syndromic and syndromic oculocutaneous albinism in human and mouse. Pigment Cell Melanoma Res 2021; 34:786-799. [PMID: 33960688 DOI: 10.1111/pcmr.12982] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 01/12/2023]
Abstract
Oculocutaneous albinism (OCA) is the most frequent presentation of albinism, a heterogeneous rare genetic condition generally associated with variable alterations in pigmentation and with a profound visual impairment. There are non-syndromic and syndromic types of OCA, depending on whether the gene product affected impairs essentially the function of melanosomes or, in addition, that of other lysosome-related organelles (LROs), respectively. Syndromic OCA can be more severe and associated with additional systemic consequences, beyond pigmentation and vision alterations. In addition to OCA, albinism can also be presented without obvious skin and hair pigmentation alterations, in ocular albinism (OA), and a related genetic condition known as foveal hypoplasia, optic nerve decussation defects, and anterior segment dysgenesis (FHONDA). In this review, we will focus only in the genetics of skin pigmentation in OCA, both in human and mouse, updating our current knowledge on this subject.
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Affiliation(s)
- Almudena Fernández
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain
| | - Masahiro Hayashi
- Department of Dermatology, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Gema Garrido
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain
| | - Andrea Montero
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain
| | - Ana Guardia
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain
| | - Tamio Suzuki
- Department of Dermatology, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Lluis Montoliu
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain
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13
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Lavinda O, Manga P, Orlow SJ, Cardozo T. Biophysical Compatibility of a Heterotrimeric Tyrosinase-TYRP1-TYRP2 Metalloenzyme Complex. Front Pharmacol 2021; 12:602206. [PMID: 33995009 PMCID: PMC8114058 DOI: 10.3389/fphar.2021.602206] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/08/2021] [Indexed: 11/20/2022] Open
Abstract
Tyrosinase (TYR) is a copper-containing monooxygenase central to the function of melanocytes. Alterations in its expression or activity contribute to variations in skin, hair and eye color, and underlie a variety of pathogenic pigmentary phenotypes, including several forms of oculocutaneous albinism (OCA). Many of these phenotypes are linked to individual missense mutations causing single nucleotide variants and polymorphisms (SNVs) in TYR. We previously showed that two TYR homologues, TYRP1 and TYRP2, modulate TYR activity and stabilize the TYR protein. Accordingly, to investigate whether TYR, TYRP1, and TYRP2 are biophysically compatible with various heterocomplexes, we computationally docked a high-quality 3D model of TYR to the crystal structure of TYRP1 and to a high-quality 3D model of TYRP2. Remarkably, the resulting TYR-TYRP1 heterodimer was complementary in structure and energy with the TYR-TYRP2 heterodimer, with TYRP1 and TYRP2 docking to different adjacent surfaces on TYR that apposed a third realistic protein interface between TYRP1-TYRP2. Hence, the 3D models are compatible with a heterotrimeric TYR-TYRP1-TYRP2 complex. In addition, this heterotrimeric TYR-TYRP1-TYRP2 positioned the C-terminus of each folded enzymatic domain in an ideal position to allow their C-terminal transmembrane helices to form a putative membrane embedded three-helix bundle. Finally, pathogenic TYR mutations causing OCA1A, which also destabilize TYR biochemically, cluster on an unoccupied protein interface at the periphery of the heterotrimeric complex, suggesting that this may be a docking site for OCA2, an anion channel. Pathogenic OCA2 mutations result in similar phenotypes to those produced by OCA1A TYR mutations. While this complex may be difficult to detect in vitro, due to the complex environment of the vertebrate cellular membranous system, our results support the existence of a heterotrimeric complex in melanogenesis.
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Affiliation(s)
- Olga Lavinda
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - Prashiela Manga
- The Ronald O. Perelman Department of Dermatology, NYU Grossman School of Medicine, New York, NY, United States
| | - Seth J Orlow
- The Ronald O. Perelman Department of Dermatology, NYU Grossman School of Medicine, New York, NY, United States
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
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14
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Feng Y, McQuillan MA, Tishkoff SA. Evolutionary genetics of skin pigmentation in African populations. Hum Mol Genet 2021; 30:R88-R97. [PMID: 33438000 PMCID: PMC8117430 DOI: 10.1093/hmg/ddab007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 12/14/2022] Open
Abstract
Skin color is a highly heritable human trait, and global variation in skin pigmentation has been shaped by natural selection, migration and admixture. Ethnically diverse African populations harbor extremely high levels of genetic and phenotypic diversity, and skin pigmentation varies widely across Africa. Recent genome-wide genetic studies of skin pigmentation in African populations have advanced our understanding of pigmentation biology and human evolutionary history. For example, novel roles in skin pigmentation for loci near MFSD12 and DDB1 have recently been identified in African populations. However, due to an underrepresentation of Africans in human genetic studies, there is still much to learn about the evolutionary genetics of skin pigmentation. Here, we summarize recent progress in skin pigmentation genetics in Africans and discuss the importance of including more ethnically diverse African populations in future genetic studies. In addition, we discuss methods for functional validation of adaptive variants related to skin pigmentation.
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Affiliation(s)
- Yuanqing Feng
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael A McQuillan
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sarah A Tishkoff
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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15
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Genetic ancestry, skin pigmentation, and the risk of cutaneous squamous cell carcinoma in Hispanic/Latino and non-Hispanic white populations. Commun Biol 2020; 3:765. [PMID: 33318654 PMCID: PMC7736583 DOI: 10.1038/s42003-020-01461-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 10/23/2020] [Indexed: 11/20/2022] Open
Abstract
Although cutaneous squamous cell carcinoma (cSCC) is one of the most common malignancies in individuals of European ancestry, the incidence of cSCC in Hispanic/Latinos is also increasing. cSCC has both a genetic and environmental etiology. Here, we examine the role of genetic ancestry, skin pigmentation, and sun exposure in Hispanic/Latinos and non-Hispanic whites on cSCC risk. We observe an increased cSCC risk with greater European ancestry (P = 1.27 × 10−42) within Hispanic/Latinos and with greater northern (P = 2.38 × 10−65) and western (P = 2.28 × 10−49) European ancestry within non-Hispanic whites. These associations are significantly, but not completely, attenuated after considering skin pigmentation-associated loci, history of actinic keratosis, and sun-protected versus sun-exposed anatomical sites. We also report an association of the well-known pigment variant Ala111Thr (rs1426654) at SLC24A5 with cSCC in Hispanic/Latinos. These findings demonstrate a strong correlation of northwestern European genetic ancestry with cSCC risk in both Hispanic/Latinos and non-Hispanic whites, largely but not entirely mediated through its impact on skin pigmentation. Eric Jorgenson and Hélène Choquet et al. find that northwestern European genetic ancestry is associated with increased risk of cutaneous squamous cell carcinoma (cSCC) in non-Hispanic whites, and more so in Hispanic/Latinos of the US. The ancestry effect is largely, but not entirely explained by genetic determinants of skin pigmentation in both populations.
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16
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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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17
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Okamura K, Suzuki T. Current landscape of Oculocutaneous Albinism in Japan. Pigment Cell Melanoma Res 2020; 34:190-203. [PMID: 32969595 DOI: 10.1111/pcmr.12927] [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: 08/24/2020] [Revised: 09/05/2020] [Accepted: 09/10/2020] [Indexed: 12/16/2022]
Abstract
Oculocutaneous albinism (OCA), which is roughly divided into non-syndromic and syndromic OCA, is a group of autosomal recessive disorders caused by mutations in genes associated with pigmentation. Patients with OCA have hypopigmentation and ocular manifestations such as photophobia, amblyopia, and nystagmus. Hermansky-Pudlak syndrome (HPS), the most common syndromic OCA, is characterized by the additional features of a bleeding tendency and other critical systemic comorbidities such as pulmonary fibrosis and immunodeficiency. NGS-based gene analyses have identified several new causative genes for OCA and have detected rare subtypes of OCA with high accuracy including Japanese patients. In our survey of 190 Japanese OCA patients/families, OCA4 is the most common subtype (25.3%) followed by OCA1 (20.0%), HPS1 (14.7%), and OCA2 (8.4%). Similar to the A481T variant in OCA2, which is associated with a mild form of OCA2 and skin color variation, the c.-492_489delAATG variant located in the promoter region of SLC45A2 has been uniquely identified in Japanese patients with a mild form of OCA4. Further, rare OCA subtypes, including OCA3, HPS2, HPS3, HPS4, HPS5, HPS6, and HPS9, have also been identified in Japanese patients. The clinical characteristics and underlying molecular mechanisms of each subtype of OCA are concisely summarized in this review.
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Affiliation(s)
- Ken Okamura
- Department of Dermatology, Faculty of Medicine, Yamagata University, Yamagata, Japan
| | - Tamio Suzuki
- Department of Dermatology, Faculty of Medicine, Yamagata University, Yamagata, Japan
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18
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Kiener S, Kehl A, Loechel R, Langbein-Detsch I, Müller E, Bannasch D, Jagannathan V, Leeb T. Novel Brown Coat Color (Cocoa) in French Bulldogs Results from a Nonsense Variant in HPS3. Genes (Basel) 2020; 11:genes11060636. [PMID: 32526956 PMCID: PMC7349258 DOI: 10.3390/genes11060636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 12/30/2022] Open
Abstract
Brown or chocolate coat color in many mammalian species is frequently due to variants at the B locus or TYRP1 gene. In dogs, five different TYRP1 loss-of-function alleles have been described, which explain the vast majority of dogs with brown coat color. Recently, breeders and genetic testing laboratories identified brown French Bulldogs that did not carry any of the known mutant TYRP1 alleles. We sequenced the genome of a TYRP1+/+ brown French Bulldog and compared the data to 655 other canine genomes. A search for private variants revealed a nonsense variant in HPS3, c.2420G>A or p.(Trp807*). The brown dog was homozygous for the mutant allele at this variant. The HPS3 gene encodes a protein required for the correct biogenesis of lysosome-related organelles, including melanosomes. Variants in the human HPS3 gene cause Hermansky–Pudlak syndrome 3, which involves a mild form of oculocutaneous albinism and prolonged bleeding time. A variant in the murine Hps3 gene causes brown coat color in the cocoa mouse mutant. We genotyped a cohort of 373 French Bulldogs and found a strong association of the homozygous mutant HPS3 genotype with the brown coat color. The genotype–phenotype association and the comprehensive knowledge on HPS3 function from other species strongly suggests that HPS3:c.2420G>A is the causative variant for the observed brown coat color in French Bulldogs. In order to clearly distinguish HPS3-related from the TYRP1-related brown coat color, and in line with the murine nomenclature, we propose to designate this dog phenotype as “cocoa”, and the mutant allele as HPS3co.
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Affiliation(s)
- Sarah Kiener
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (S.K.); (D.B.); (V.J.)
- Dermfocus, University of Bern, 3001 Bern, Switzerland
| | - Alexandra Kehl
- Laboklin, 97688 Bad Kissingen, Germany; (A.K.); (I.L.-D.); (E.M.)
| | | | | | - Elisabeth Müller
- Laboklin, 97688 Bad Kissingen, Germany; (A.K.); (I.L.-D.); (E.M.)
| | - Danika Bannasch
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (S.K.); (D.B.); (V.J.)
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (S.K.); (D.B.); (V.J.)
- Dermfocus, University of Bern, 3001 Bern, Switzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (S.K.); (D.B.); (V.J.)
- Dermfocus, University of Bern, 3001 Bern, Switzerland
- Correspondence: ; Tel.: +41-3163-123-26
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19
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Onojafe IF, Megan LH, Melch MG, Aderemi JO, Alur RP, Abu-Asab MS, Chan CC, Bernardini IM, Albert JS, Cogliati T, Adams DR, Brooks BP. Minimal Efficacy of Nitisinone Treatment in a Novel Mouse Model of Oculocutaneous Albinism, Type 3. Invest Ophthalmol Vis Sci 2019; 59:4945-4952. [PMID: 30347088 PMCID: PMC6181301 DOI: 10.1167/iovs.16-20293] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Purpose Oral nitisinone has been shown to increase fur and ocular pigmentation in a mouse model of oculocutaneous albinism (OCA) due to hypomorphic mutations in tyrosinase (TYR), OCA1B. This study determines if nitisinone can improve ocular and/or fur pigmentation in a mouse model of OCA type 3 (OCA3), caused by mutation of the tyrosinase-related protein 1 (Tyrp1) gene. Methods Mice homozygous for a null allele in the Tyrp1 gene (C57BL/6J-Tyrp1 b-J/J) were treated with 8 mg/kg nitisinone or vehicle every other day by oral gavage. Changes in fur and ocular melanin pigmentation were monitored. Mature ocular melanosome number and size were quantified in pigmented ocular structures by electron microscopy. Results C57BL/6J-Tyrp1 b-J/J mice carry a novel c.403T>A; 404delG mutation in Tyrp1, predicted to result in premature truncation of the TYRP1 protein. Nitisinone treatment resulted in an approximately 7-fold increase in plasma tyrosine concentrations without overt toxicity. After 1 month of treatment, no change in the color of fur or pigmented ocular structures was observed. The distribution of melanosome cross-sectional area was unchanged in ocular tissues. There was no significant difference in the number of pigmented melanosomes in the RPE/choroid of nitisinone-treated and control groups. However, there was a significant difference in the number of pigmented melanosomes in the iris. Conclusions Treatment of a mouse model of OCA3 with oral nitisinone did not have a favorable clinical effect on melanin production and minimally affected the number of pigmented melanosomes in the iris stroma. As such, treatment of OCA3 patients with nitisinone is unlikely to be therapeutic.
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Affiliation(s)
- Ighovie F Onojafe
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Lucyanne H Megan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Madeline G Melch
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Joseph O Aderemi
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Ramakrishna P Alur
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Mones S Abu-Asab
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Chi-Chao Chan
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Isa M Bernardini
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Jessica S Albert
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Tiziana Cogliati
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - David R Adams
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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20
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Gul H, Shah AH, Harripaul R, Mikhailov A, Prajapati K, Khan E, Ullah F, Zubair M, Ali MZ, Shah AH, Salman S, Khan S, Vincent JB, Khan MA. Genetic studies of multiple consanguineous Pakistani families segregating oculocutaneous albinism identified novel and reported mutations. Ann Hum Genet 2019; 83:278-284. [PMID: 30868578 DOI: 10.1111/ahg.12307] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 02/05/2019] [Accepted: 02/18/2019] [Indexed: 11/28/2022]
Abstract
Oculocutaneous albinism (OCA) is an autosomal-recessive disorder of a defective melanin pathway. The condition is characterized by hypopigmentation of hair, dermis, and ocular tissue. Genetic studies have reported seven nonsyndromic OCA genes, among which Pakistani OCA families mostly segregate TYR and OCA2 gene mutations. Here in the present study, we investigate the genetic factors of eight consanguineous OCA families from Pakistan. Genetic analysis was performed through single-nucleotide polymorphism (SNP) genotyping (for homozygosity mapping), whole exome sequencing (for mutation identification), Sanger sequencing (for validation and segregation analysis), and quantitative PCR (qPCR) (for copy number variant [CNV] validation). Genetic mapping in one family identified a novel homozygous deletion mutation of the entire TYRP1 gene, and a novel deletion of exon 19 in the OCA2 gene in two apparently unrelated families. In three further families, we identified homozygous mutations in TYR (NM_000372.4:c.1424G > A; p.Trp475*), NM_000372.4:c.895C > T; p.Arg299Cys), and SLC45A2 (NM_016180:c.1532C > T; p.Ala511Val). For the remaining two families, G and H, compound heterozygous TYR variants NM_000372.4:c.1037-7T > A, NM_000372.4:c.1255G > A (p.Gly419Arg), and NM_000372.4:c.1255G > A (p.Gly419Arg) and novel variant NM_000372.4:c.248T > G; (p.Val83Gly), respectively, were found. Our study further extends the evidence of TYR and OCA2 as genetic mutation hot spots in Pakistani families. Genetic screening of additional OCA cases may also contribute toward the development of Pakistani specific molecular diagnostic tests, genetic counseling, and personalized healthcare.
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Affiliation(s)
- Hadia Gul
- Department of Biological Sciences, Faculty of Sciences, Gomal University, D.I. Khan, Pakistan
| | - Abdul Haleem Shah
- Department of Biological Sciences, Faculty of Sciences, Gomal University, D.I. Khan, Pakistan
| | - Ricardo Harripaul
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada
| | - Anna Mikhailov
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada
| | - Kamalben Prajapati
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada
| | - Ejazullah Khan
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Farman Ullah
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Muhammad Zubair
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan.,Department of Cell and Developmental Biology, School of Life Sciences, University of Science and Technology, Hefei, China
| | - Muhammad Zeeshan Ali
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
| | - Ayesha Haleem Shah
- Department of Biological Sciences, Faculty of Sciences, Gomal University, D.I. Khan, Pakistan
| | - Said Salman
- Department of Plant Breeding and Genetics, Ghazi University, D.G. Khan, Pakistan
| | - Saadullah Khan
- Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology, Kohat, Pakistan
| | - John B Vincent
- Molecular Neuro-Psychiatry and Development Lab (MiND), Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Muzammil Ahmad Khan
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Pakistan
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21
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McKay BS. Pigmentation and vision: Is GPR143 in control? J Neurosci Res 2019; 97:77-87. [PMID: 29761529 PMCID: PMC6235735 DOI: 10.1002/jnr.24246] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/21/2018] [Accepted: 03/21/2018] [Indexed: 12/30/2022]
Abstract
Albinism, typically characterized by decreased melanin synthesis, is associated with significant visual deficits owing to developmental changes during neurosensory retina development. All albinism is caused by genetic mutations in a group of diverse genes including enzymes, transporters, G-protein coupled receptor. Interestingly, these genes are not expressed in the neurosensory retina. Further, regardless of cause of albinism, all forms of albinism have the same retinal pathology, the extent of which is variable. In this review, we explore the possibility that this similarity in retinal phenotype is because all forms of albinism funnel through the same final common pathway. There are currently seven known genes linked to the seven forms of ocular cutaneous albinism. These types of albinism are the most common, and result in changes to all pigmented tissues (hair, skin, eyes). We will discuss the incidence and mechanism, where known, to develop a picture as to how the mutations cause albinism. Next, we will examine the one form of albinism which causes tissue-specific pathology, ocular albinism, where the eye exhibits the retinal albinism phenotype despite near normal melanin synthesis. We will discuss a potential way to treat the disease and restore normal retinal development. Finally, we will briefly discuss the possibility that this same pathway may intersect with the most common cause of permanent vision loss in the elderly.
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Affiliation(s)
- Brian S McKay
- Department of Ophthalmology and Vision Science, University of Arizona, Tucson, Arizona
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22
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Li J, Bed’hom B, Marthey S, Valade M, Dureux A, Moroldo M, Péchoux C, Coville J, Gourichon D, Vieaud A, Dorshorst B, Andersson L, Tixier‐Boichard M. A missense mutation in
TYRP1
causes the chocolate plumage color in chicken and alters melanosome structure. Pigment Cell Melanoma Res 2018; 32:381-390. [DOI: 10.1111/pcmr.12753] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 09/19/2018] [Accepted: 10/02/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Jingyi Li
- Department of Animal and Poultry Sciences Virginia Tech Blacksburg Virginia
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station Texas
| | - Bertrand Bed’hom
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | - Sylvain Marthey
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | - Mathieu Valade
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | - Audrey Dureux
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | - Marco Moroldo
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | - Christine Péchoux
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | - Jean‐Luc Coville
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | | | - Agathe Vieaud
- GABI, AgroParisTech, INRA Université Paris‐Saclay Jouy‐en‐Josas France
| | - Ben Dorshorst
- Department of Animal and Poultry Sciences Virginia Tech Blacksburg Virginia
| | - Leif Andersson
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences Texas A&M University College Station Texas
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology Uppsala University Uppsala Sweden
- Department of Animal Breeding and Genetics Swedish University of Agricultural Sciences Uppsala Sweden
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23
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Comprehensive Review of the Genetics of Albinism. JOURNAL OF VISUAL IMPAIRMENT & BLINDNESS 2018. [DOI: 10.1177/0145482x1811200604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Introduction It is important to understand albinism, since it is a disorder associated with visual impairment, predisposition to malignant melanomas, and social stigma. The main objective of this article is to review the genetics and biologic mechanisms of the non-syndromic albinism subtypes and to describe associated clinical manifestations. We also discuss research on its treatments. Methods A review of the published literature on albinism subtypes was performed, spanning basic laboratory research, published case reports, and experiences of people with albinism. Results Clear progress has been made in comprehending the causes of albinism; research has shed light on the complexity of the disorder and has led to the molecular classification of subtypes. Discussion Despite the increase in knowledge with regards to albinism, gaps still exist. It is important to continue the pursuit of unraveling the mechanism of the disorder and to monitor the frequency of the subtypes worldwide in order to aid in the development of treatments. Furthermore, disseminating knowledge of albinism is crucial for future progress. Implications for practitioners Albinism is a disorder characterized by hypopigmentation of the hair, skin, and eyes, with accompanying ocular abnormalities that remain relatively stable throughout life. The disorder is defined by a spectrum of pigmentation where albinism is more evident among individuals of dark complexion than their lighter-pigmented peers. Patients with albinism require protection against sun exposure and special resources to address visual impairments. When albinism patients are diagnosed and properly accommodated, they generally report a positive quality of life.
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24
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Krause A, Seymour H, Ramsay M. Common and Founder Mutations for Monogenic Traits in Sub-Saharan African Populations. Annu Rev Genomics Hum Genet 2018; 19:149-175. [DOI: 10.1146/annurev-genom-083117-021256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review highlights molecular genetic studies of monogenic traits where common pathogenic mutations occur in black families from sub-Saharan Africa. Examples of founder mutations have been identified for oculocutaneous albinism, cystic fibrosis, Fanconi anemia, and Gaucher disease. Although there are few studies from Africa, some of the mutations traverse populations across the continent, and they are almost all different from the common mutations observed in non-African populations. Myotonic dystrophy is curiously absent among Africans, and nonsyndromic deafness does not arise from mutations in GJB2 and GJB7. Locus heterogeneity is present for Huntington disease, with two common triplet expansion loci in Africa, HTT and JPH3. These findings have important clinical consequences for diagnosis, treatment, and genetic counseling in affected families. We currently have just a glimpse of the molecular etiology of monogenic diseases in sub-Saharan Africa, a proverbial “ears of the hippo” situation.
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Affiliation(s)
- Amanda Krause
- Division of Human Genetics, National Health Laboratory Service, and Division of Human Genetics, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Heather Seymour
- Division of Human Genetics, National Health Laboratory Service, and Division of Human Genetics, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Michèle Ramsay
- Division of Human Genetics, National Health Laboratory Service, and Division of Human Genetics, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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25
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Ali SA, Naaz I. Biochemical aspects of mammalian melanocytes and the emerging role of melanocyte stem cells in dermatological therapies. Int J Health Sci (Qassim) 2018; 12:69-76. [PMID: 29623021 PMCID: PMC5870308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Skin color in animals is richer than human beings and is determined by different types of pigments. Melanin is the key pigment responsible for the diverse pigmentation found in animal and human skin, hair, and eyes. Melanin pigment is synthesized by melanocytes and is consecutively transferred to adjacent keratinocytes; here, it acts as an internal sunscreen to defend from ultraviolet (UV) damage. Any defect in the process of melanocytes development and/or melanin synthesis results in esthetic problem of abnormal pigmentation. Clinically, abnormal pigmentation displays distinct increased or reduced pigment levels, known as hyperpigmentation or hypopigmentation. These defects affect either the melanocyte number or its function. Herein, we discuss the fundamental aspects of melanocytes/melanin biology taken together the underlying cause of pigmentary disorders. The current chapter also gives an insight into the melanocyte stem cells biology, which in turn can facilitate the development of novel treatment regimens for dermatological disorders.
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Affiliation(s)
- Sharique A. Ali
- Department of Biotechnology, Saifia Science College, Bhopal, Madhya Pradesh, India,Address for correspondence: Dr. Sharique A. Ali, Department of Biotechnology, Saifia Science College, Bhopal, Madhya Pradesh, India. Phone: +91-9893 015818. E-mail:
| | - Ishrat Naaz
- Department of Biotechnology, Saifia Science College, Bhopal, Madhya Pradesh, India
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26
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Dolinska MB, Kus NJ, Farney SK, Wingfield PT, Brooks BP, Sergeev YV. Oculocutaneous albinism type 1: link between mutations, tyrosinase conformational stability, and enzymatic activity. Pigment Cell Melanoma Res 2017; 30:41-52. [PMID: 27775880 DOI: 10.1111/pcmr.12546] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022]
Abstract
Oculocutaneous albinism type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. Two subtypes of OCA1 have been described: severe OCA1A with complete absence of tyrosinase activity and less severe OCA1B with residual tyrosinase activity. Here, we characterize the recombinant human tyrosinase intramelanosomal domain and mutant variants, which mimic genetic changes in both subtypes of OCA1 patients. Proteins were prepared using site-directed mutagenesis, expressed in insect larvae, purified by chromatography, and characterized by enzymatic activities, tryptophan fluorescence, and Gibbs free energy changes. The OCA1A mutants showed very low protein expression and protein yield and are enzymatically inactive. Mutants mimicking OCA1B were biochemically similar to the wild type, but exhibited lower specific activities and protein stabilities. The results are consistent with clinical data, which indicates that OCA1A mutations inactivate tyrosinase and result in severe phenotype, while OCA1B mutations partially inactivate tyrosinase and result in OCA1B albinism.
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Affiliation(s)
- Monika B Dolinska
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Nicole J Kus
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - S Katie Farney
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Paul T Wingfield
- National Institute of Artritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Brian P Brooks
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yuri V Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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27
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Marti A, Lasseaux E, Ezzedine K, Léauté-Labrèze C, Boralevi F, Paya C, Coste V, Deroissart V, Arveiler B, Taieb A, Morice-Picard F. Lessons of a day hospital: Comprehensive assessment of patients with albinism in a European setting. Pigment Cell Melanoma Res 2017; 31:318-329. [DOI: 10.1111/pcmr.12651] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 09/22/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Aurélie Marti
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
| | | | - Khaled Ezzedine
- Department of Dermatology; AP-HP; Hôpital Henri-Mondor; Créteil France
| | - Christine Léauté-Labrèze
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
| | - Franck Boralevi
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
| | - Clément Paya
- Ophthalmology Department; CHU de Bordeaux; Bordeaux France
| | | | - Vincent Deroissart
- Institute of Public Health; Epidemiology and Development “ISPED”; Bordeaux University; Bordeaux France
| | - Benoit Arveiler
- Molecular Genetics Laboratory; CHU de Bordeaux; Bordeaux France
- Unité INSERM U1211; Maladies Rares: Génétique et Métabolisme; Bordeaux France
| | - Alain Taieb
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
- Unité INSERM 1035; BMGIC; Immuno-dermatology ATIP-AVENIR; University of Bordeaux; Bordeaux France
| | - Fanny Morice-Picard
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
- Molecular Genetics Laboratory; CHU de Bordeaux; Bordeaux France
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28
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Decker H, Tuczek F. Die erste Kristallstruktur des humanen Tyrosinase-ähnlichen Proteins 1 (HsTYRP1) löst ein altes Problem und wirft ein neues auf. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Heinz Decker
- Institut für Molekulare Biologie; Johannes-Gutenberg-Universität Mainz; Jakob Welder Weg 26 55128 Mainz Deutschland
| | - Felix Tuczek
- Institut für Anorganische Chemie; Christian-Albrechts-Universität zu Kiel; Deutschland
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29
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Decker H, Tuczek F. The Recent Crystal Structure of Human Tyrosinase Related Protein 1 (HsTYRP1) Solves an Old Problem and Poses a New One. Angew Chem Int Ed Engl 2017; 56:14352-14354. [DOI: 10.1002/anie.201708214] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Heinz Decker
- Institute of Molecular Biology; Johannes Gutenberg-University; Jacob Welder Weg 26 55128 Mainz Germany
| | - Felix Tuczek
- Institute of Inorganic Chemistry; Christian Alberts University Kiel; Max Eyth Strasse 2 24118 Kiel Germany
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30
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Two Variants in SLC24A5 Are Associated with "Tiger-Eye" Iris Pigmentation in Puerto Rican Paso Fino Horses. G3-GENES GENOMES GENETICS 2017; 7:2799-2806. [PMID: 28655738 PMCID: PMC5555483 DOI: 10.1534/g3.117.043786] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A unique eye color, called tiger-eye, segregates in the Puerto Rican Paso Fino (PRPF) horse breed and is characterized by a bright yellow, amber, or orange iris. Pedigree analysis identified a simple autosomal recessive mode of inheritance for this trait. A genome-wide association study (GWAS) with 24 individuals identified a locus on ECA 1 reaching genome-wide significance (Pcorrected = 1.32 × 10−5). This ECA1 locus harbors the candidate gene, Solute Carrier Family 24 (Sodium/Potassium/Calcium Exchanger), Member 5 (SLC24A5), with known roles in pigmentation in humans, mice, and zebrafish. Humans with compound heterozygous mutations in SLC24A5 have oculocutaneous albinism (OCA) type 6 (OCA6), which is characterized by dilute skin, hair, and eye pigmentation, as well as ocular anomalies. Twenty tiger-eye horses were homozygous for a nonsynonymous mutation in exon 2 (p.Phe91Tyr) of SLC24A5 (called here Tiger-eye 1), which is predicted to be deleterious to protein function. Additionally, eight of the remaining 12 tiger-eye horses heterozygous for the p.Phe91Tyr variant were also heterozygous for a 628 bp deletion encompassing all of exon 7 of SLC24A5 (c.875-340_1081+82del), which we will call here the Tiger-eye 2 allele. None of the 122 brown-eyed horses were homozygous for either tiger-eye-associated allele or were compound heterozygotes. Further, neither variant was detected in 196 horses from four related breeds not known to have the tiger-eye phenotype. Here, we propose that two mutations in SLC24A5 affect iris pigmentation in tiger-eye PRPF horses. Further, unlike OCA6 in humans, the Tiger-eye 1 mutation in its homozygous state or as a compound heterozygote (Tiger-eye 1/Tiger-eye 2) does not appear to cause ocular anomalies or a change in coat color in the PRPF horse.
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31
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Bhak Y, Jeon Y, Jeon S, Chung O, Jho S, Jun J, Kim HM, Cho Y, Yoon C, Lee S, Kang JH, Lim JD, An J, Cho YS, Ryu DY, Bhak J. Myotis rufoniger genome sequence and analyses: M. rufoniger's genomic feature and the decreasing effective population size of Myotis bats. PLoS One 2017; 12:e0180418. [PMID: 28678835 PMCID: PMC5498047 DOI: 10.1371/journal.pone.0180418] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 05/23/2017] [Indexed: 12/14/2022] Open
Abstract
Myotis rufoniger is a vesper bat in the genus Myotis. Here we report the whole genome sequence and analyses of the M. rufoniger. We generated 124 Gb of short-read DNA sequences with an estimated genome size of 1.88 Gb at a sequencing depth of 66× fold. The sequences were aligned to M. brandtii bat reference genome at a mapping rate of 96.50% covering 95.71% coding sequence region at 10× coverage. The divergence time of Myotis bat family is estimated to be 11.5 million years, and the divergence time between M. rufoniger and its closest species M. davidii is estimated to be 10.4 million years. We found 1,239 function-altering M. rufoniger specific amino acid sequences from 929 genes compared to other Myotis bat and mammalian genomes. The functional enrichment test of the 929 genes detected amino acid changes in melanin associated DCT, SLC45A2, TYRP1, and OCA2 genes possibly responsible for the M. rufoniger's red fur color and a general coloration in Myotis. N6AMT1 gene, associated with arsenic resistance, showed a high degree of function alteration in M. rufoniger. We further confirmed that the M. rufoniger also has bat-specific sequences within FSHB, GHR, IGF1R, TP53, MDM2, SLC45A2, RGS7BP, RHO, OPN1SW, and CNGB3 genes that have already been published to be related to bat's reproduction, lifespan, flight, low vision, and echolocation. Additionally, our demographic history analysis found that the effective population size of Myotis clade has been consistently decreasing since ~30k years ago. M. rufoniger's effective population size was the lowest in Myotis bats, confirming its relatively low genetic diversity.
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Affiliation(s)
- Youngjune Bhak
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Yeonsu Jeon
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Sungwon Jeon
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Oksung Chung
- Personal Genomics Institute, Genome Research Foundation, Cheongju, Republic of Korea
- Geromics, Ulsan, Republic of Korea
| | - Sungwoong Jho
- Personal Genomics Institute, Genome Research Foundation, Cheongju, Republic of Korea
| | - JeHoon Jun
- Personal Genomics Institute, Genome Research Foundation, Cheongju, Republic of Korea
- Geromics, Ulsan, Republic of Korea
| | - Hak-Min Kim
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Yongsoo Cho
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Changhan Yoon
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Science, School of Nano-Bioscience & chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Seungwoo Lee
- BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science, and College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jung-Hoon Kang
- National Research Institute of Cultural Heritage, Cultural Heritage Administration, Daejeon, Republic of Korea
| | - Jong-Deock Lim
- National Research Institute of Cultural Heritage, Cultural Heritage Administration, Daejeon, Republic of Korea
| | - Junghwa An
- Animal Resources Division, National Institute of Biological Resources, Incheon, Republic of Korea
| | - Yun Sung Cho
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Personal Genomics Institute, Genome Research Foundation, Cheongju, Republic of Korea
| | - Doug-Young Ryu
- BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science, and College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jong Bhak
- The Genomics Institute, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Personal Genomics Institute, Genome Research Foundation, Cheongju, Republic of Korea
- Geromics, Ulsan, Republic of Korea
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Retinal pigment epithelium findings in patients with albinism using wide-field polarization-sensitive optical coherence tomography. Retina 2015; 34:2208-17. [PMID: 25046395 DOI: 10.1097/iae.0000000000000224] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate pigmentation characteristics of the retinal pigment epithelium (RPE) in patients with albinism using wide-field polarization-sensitive optical coherence tomography compared with intensity-based spectral domain optical coherence tomography and fundus autofluorescence imaging. METHODS Five patients (10 eyes) with previously genetically diagnosed albinism and 5 healthy control subjects (10 eyes) were imaged by a wide-field polarization-sensitive optical coherence tomography system (scan angle: 40 × 40° on the retina), sensitive to melanin contained in the RPE, based on the polarization state of backscattered light. Conventional intensity-based spectral domain optical coherence tomography and fundus autofluorescence examinations were performed. Retinal pigment epithelium-pigmentation was analyzed qualitatively and quantitatively based on depolarization assessed by polarization-sensitive optical coherence tomography. RESULTS This study revealed strong evidence of polarization-sensitive optical coherence tomography to specifically image melanin in the RPE. Depolarization of light backscattered by the RPE in patients with albinism was reduced compared with normal subjects. Heterogeneous RPE-specific depolarization characteristics were observed in patients with albinism. Reduction of depolarization observed in the light backscattered by the RPE in patients with albinism corresponds to expected decrease of RPE pigmentation. The degree of depigmentation of the RPE is possibly associated with visual acuity. Findings suggest that different albinism genotypes result in heterogeneous levels of RPE pigmentation. CONCLUSION Polarization-sensitive optical coherence tomography showed a heterogeneous appearance of RPE pigmentation in patients with albinism depending on different genotypes.
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Wright CY, Norval M, Hertle RW. Oculocutaneous albinism in sub-Saharan Africa: adverse sun-associated health effects and photoprotection. Photochem Photobiol 2014; 91:27-32. [PMID: 25298350 DOI: 10.1111/php.12359] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 10/01/2014] [Indexed: 01/15/2023]
Abstract
Oculocutaneous albinism (OCA) is a genetically inherited autosomal recessive condition. Individuals with OCA lack melanin and therefore are susceptible to the harmful effects of solar ultraviolet radiation, including extreme sun sensitivity, photophobia and skin cancer. OCA is a grave public health issue in sub-Saharan Africa with a prevalence as high as 1 in 1000 in some tribes. This article considers the characteristics and prevalence of OCA in sub-Saharan African countries. Sun-induced adverse health effects in the skin and eyes of OCA individuals are reviewed. Sun exposure behavior and the use of photoprotection for the skin and eyes are discussed to highlight the major challenges experienced by these at-risk individuals and how these might be best resolved.
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Affiliation(s)
- Caradee Y Wright
- Climate Studies, Modelling and Environmental Health Research Group, Council for Scientific and Industrial Research, Pretoria, South Africa; Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africa
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Haltaufderhyde KD, Oancea E. Genome-wide transcriptome analysis of human epidermal melanocytes. Genomics 2014; 104:482-9. [PMID: 25451175 DOI: 10.1016/j.ygeno.2014.09.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/19/2014] [Accepted: 09/22/2014] [Indexed: 01/09/2023]
Abstract
Because human epidermal melanocytes (HEMs) provide critical protection against skin cancer, sunburn, and photoaging, a genome-wide perspective of gene expression in these cells is vital to understanding human skin physiology. In this study we performed high throughput sequencing of HEMs to obtain a complete data set of transcript sizes, abundances, and splicing. As expected, we found that melanocyte specific genes that function in pigmentation were among the highest expressed genes. We analyzed receptor, ion channel and transcription factor gene families to get a better understanding of the cell signaling pathways used by melanocytes. We also performed a comparative transcriptomic analysis of lightly versus darkly pigmented HEMs and found 16 genes differentially expressed in the two pigmentation phenotypes; of those, only one putative melanosomal transporter (SLC45A2) has known function in pigmentation. In addition, we found 166 transcript isoforms expressed exclusively in one pigmentation phenotype, 17 of which are genes involved in signal transduction. Our melanocyte transcriptome study provides a comprehensive view and may help identify novel pigmentation genes and potential pharmacological targets.
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Affiliation(s)
- Kirk D Haltaufderhyde
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02192, USA
| | - Elena Oancea
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02192, USA.
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Tyrosinase-related protein 1 (TYRP1) gene polymorphism and skin differential expression related to coat color in Mongolian horse. Livest Sci 2014. [DOI: 10.1016/j.livsci.2014.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Kraft S, Granter SR. Molecular pathology of skin neoplasms of the head and neck. Arch Pathol Lab Med 2014; 138:759-87. [PMID: 24878016 DOI: 10.5858/arpa.2013-0157-ra] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region. OBJECTIVE To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations. DATA SOURCES Literature review. CONCLUSIONS Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.
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Affiliation(s)
- Stefan Kraft
- From the Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (Dr Kraft); and the Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts (Dr Granter)
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Wilk MA, McAllister JT, Cooper RF, Dubis AM, Patitucci TN, Summerfelt P, Anderson JL, Stepien KE, Costakos DM, Connor TB, Wirostko WJ, Chiang PW, Dubra A, Curcio CA, Brilliant MH, Summers CG, Carroll J. Relationship between foveal cone specialization and pit morphology in albinism. Invest Ophthalmol Vis Sci 2014; 55:4186-98. [PMID: 24845642 DOI: 10.1167/iovs.13-13217] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Albinism is associated with disrupted foveal development, though intersubject variability is becoming appreciated. We sought to quantify this variability, and examine the relationship between foveal cone specialization and pit morphology in patients with a clinical diagnosis of albinism. METHODS We recruited 32 subjects with a clinical diagnosis of albinism. DNA was obtained from 25 subjects, and known albinism genes were analyzed for mutations. Relative inner and outer segment (IS and OS) lengthening (fovea-to-perifovea ratio) was determined from manually segmented spectral domain-optical coherence tomography (SD-OCT) B-scans. Foveal pit morphology was quantified for eight subjects from macular SD-OCT volumes. Ten subjects underwent imaging with adaptive optics scanning light ophthalmoscopy (AOSLO), and cone density was measured. RESULTS We found mutations in 22 of 25 subjects, including five novel mutations. All subjects lacked complete excavation of inner retinal layers at the fovea, though four subjects had foveal pits with normal diameter and/or volume. Peak cone density and OS lengthening were variable and overlapped with that observed in normal controls. A fifth hyper-reflective band was observed in the outer retina on SD-OCT in the majority of the subjects with albinism. CONCLUSIONS Foveal cone specialization and pit morphology vary greatly in albinism. Normal cone packing was observed in the absence of a foveal pit, suggesting a pit is not required for packing to occur. The degree to which retinal anatomy correlates with genotype or visual function remains unclear, and future examination of larger patient groups will provide important insight on this issue.
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Affiliation(s)
- Melissa A Wilk
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - John T McAllister
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Robert F Cooper
- Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin, United States
| | - Adam M Dubis
- Moorfields Eye Hospital, London, United Kingdom Institute of Ophthalmology, University College London, United Kingdom
| | - Teresa N Patitucci
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Phyllis Summerfelt
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | | | - Kimberly E Stepien
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Deborah M Costakos
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Thomas B Connor
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - William J Wirostko
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Pei-Wen Chiang
- Casey Eye Institute Molecular Diagnostics Laboratory, Portland, Oregon, United States
| | - Alfredo Dubra
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin, United States Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Christine A Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, Alabama, United States
| | - Murray H Brilliant
- Center for Human Genetics, Marshfield Clinic, Marshfield, Wisconsin, United States
| | - C Gail Summers
- Departments of Ophthalmology and Visual Neurosciences and Pediatrics, University of Minnesota, Minneapolis, Minnesota, United States
| | - Joseph Carroll
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin, United States Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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Rooryck C, Morice F, Lacombe D, Taieb A, Arveiler B. Genetic basis of oculocutaneous albinism. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.09.53] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hawkes JE, Cassidy PB, Manga P, Boissy RE, Goldgar D, Cannon-Albright L, Florell SR, Leachman SA. Report of a novel OCA2 gene mutation and an investigation of OCA2 variants on melanoma risk in a familial melanoma pedigree. J Dermatol Sci 2013; 69:30-7. [PMID: 23103111 PMCID: PMC4775076 DOI: 10.1016/j.jdermsci.2012.09.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 08/26/2012] [Accepted: 09/27/2012] [Indexed: 11/21/2022]
Abstract
BACKGROUND Oculocutaneous albinism type 2 (OCA2) is caused by mutations of the OCA2 gene. Individuals affected by OCA2 as well as other types of albinism are at a significantly increased risk for sun-induced skin-cancers, including malignant melanoma (MM). OBJECTIVE To identify the molecular etiology of oculocutaneous albinism in a previously uncharacterized melanoma pedigree and to investigate the relationship between two OCA2 variants and melanoma predisposition in this pedigree. METHODS DNA and RNA were isolated from the peripheral blood of seven patients in a familial melanoma pedigree. Electron microscopy was performed on the individual with clinical oculocutaneous albinism. OCA2, TYRP1, MC1R, CDKN2A/p16, CDKN2A/p19ARF, and CDK4 genes were sequenced in affected individuals. The relationship between OCA2 variants and melanoma was assessed using a pedigree likelihood-based method. RESULTS The proband was determined to be an OCA2 compound heterozygous mutation carrier with a previously reported conservative missense mutation (V443I) and a novel non-conservative missense mutation (L734R). The pedigree contained individuals diagnosed with both cutaneous and iris melanoma. Based on co-segregation analysis, the odds of these OCA2 variants being high penetrance loci for melanoma was: 1.3-to-1 if we include the iris melanoma as affected and 6.5-to-1 if we only consider cutaneous melanoma as affected. CONCLUSION The discovery of this novel OCA2 variant adds to the body of evidence on the detrimental effects of OCA2 gene mutations on pigmentation, supports existing GWAS data on the relevance of the OCA2 gene in melanoma predisposition, and may ultimately assist in the development of targeted molecular therapies in the treatment of OCA and melanoma.
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Affiliation(s)
- Jason E. Hawkes
- Huntsman Cancer Institute and Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
| | - Pamela B. Cassidy
- Huntsman Cancer Institute and Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
- Department of Medicinal Chemistry L.S. Skagg's Pharmacy, University of Utah Health Sciences Center, Salt Lake City, UT, USA
| | - Prashiela Manga
- Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, NY, USA
| | - Raymond E. Boissy
- Department of Dermatology, University of Cincinnati, Cincinnati, OH, USA
| | - David Goldgar
- Huntsman Cancer Institute and Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
| | - Lisa Cannon-Albright
- Department of Biomedical Informatics, Huntsman Cancer Institute, Salt Lake City, UT, USA
| | - Scott R. Florell
- Huntsman Cancer Institute and Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
| | - Sancy A. Leachman
- Huntsman Cancer Institute and Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, UT, USA
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Genetic studies of TYRP1 and SLC45A2 in Pakistani patients with nonsyndromic oculocutaneous albinism. J Invest Dermatol 2012. [PMID: 23190901 DOI: 10.1038/jid.2012.432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Damé MCF, Xavier GM, Oliveira-Filho JP, Borges AS, Oliveira HN, Riet-Correa F, Schild AL. A nonsense mutation in the tyrosinase gene causes albinism in water buffalo. BMC Genet 2012; 13:62. [PMID: 22817390 PMCID: PMC3411452 DOI: 10.1186/1471-2156-13-62] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 07/20/2012] [Indexed: 11/29/2022] Open
Abstract
Background Oculocutaneous albinism (OCA) is an autosomal recessive hereditary pigmentation disorder affecting humans and several other animal species. Oculocutaneous albinism was studied in a herd of Murrah buffalo to determine the clinical presentation and genetic basis of albinism in this species. Results Clinical examinations and pedigree analysis were performed in an affected herd, and wild-type and OCA tyrosinase mRNA sequences were obtained. The main clinical findings were photophobia and a lack of pigmentation of the hair, skin, horns, hooves, mucosa, and iris. The results of segregation analysis suggest that this disease is acquired through recessive inheritance. In the OCA buffalo, a single-base substitution was detected at nucleotide 1,431 (G to A), which leads to the conversion of tryptophan into a stop codon at residue 477. Conclusion This premature stop codon produces an inactive protein, which is responsible for the OCA buffalo phenotype. These findings will be useful for future studies of albinism in buffalo and as a possible model to study diseases caused by a premature stop codon.
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Kenny EE, Timpson NJ, Sikora M, Yee MC, Moreno-Estrada A, Eng C, Huntsman S, Burchard EG, Stoneking M, Bustamante CD, Myles S. Melanesian blond hair is caused by an amino acid change in TYRP1. Science 2012; 336:554. [PMID: 22556244 DOI: 10.1126/science.1217849] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Naturally blond hair is rare in humans and found almost exclusively in Europe and Oceania. Here, we identify an arginine-to-cysteine change at a highly conserved residue in tyrosinase-related protein 1 (TYRP1) as a major determinant of blond hair in Solomon Islanders. This missense mutation is predicted to affect catalytic activity of TYRP1 and causes blond hair through a recessive mode of inheritance. The mutation is at a frequency of 26% in the Solomon Islands, is absent outside of Oceania, represents a strong common genetic effect on a complex human phenotype, and highlights the importance of examining genetic associations worldwide.
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Affiliation(s)
- Eimear E Kenny
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
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Yamada M, Sakai K, Hayashi M, Hozumi Y, Abe Y, Kawaguchi M, Ihn H, Suzuki T. Oculocutaneous albinism type 3: A Japanese girl with novel mutations in TYRP1 gene. J Dermatol Sci 2011; 64:217-22. [DOI: 10.1016/j.jdermsci.2011.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 09/07/2011] [Accepted: 09/09/2011] [Indexed: 12/11/2022]
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Manga P, Orlow SJ. Informed reasoning: repositioning of nitisinone to treat oculocutaneous albinism. J Clin Invest 2011; 121:3828-31. [PMID: 21968107 DOI: 10.1172/jci59763] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a group of genetic disorders characterized by hypopigmentation of the skin, hair, and eyes. Affected individuals experience reduced visual acuity and substantially increased skin cancer risk. There are four major types of OCA (OCA1-OCA4) that result from disruption in production of melanin from tyrosine. Current treatment options for individuals with OCA are limited to attempts to correct visual problems and counseling to promote use of sun protective measures. However, Onojafe et al., reporting in this issue of the JCI, provide hope for a new treatment approach for OCA, as they demonstrate that treating mice that model OCA-1b with nitisinone, which is FDA approved for treating hereditary tyrosinemia type 1, elevates plasma tyrosine levels, and increases eye and hair pigmentation.
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Affiliation(s)
- Prashiela Manga
- Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, New York 10016, USA
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Lu H, Li L, Watson ER, Williams RW, Geisert EE, Jablonski MM, Lu L. Complex interactions of Tyrp1 in the eye. Mol Vis 2011; 17:2455-68. [PMID: 21976956 PMCID: PMC3185026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 09/12/2011] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To use a systems genetics approach to construct and analyze co-expression networks that are causally linked to mutations in a key pigementation gene, tyrosinase-related protein 1 (Tyrp1), that is associated both with oculocutaneous albinism type 3 (OCA3) in humans and with glaucoma in mice. METHODS Gene expression patterns were measured in whole eyes of a large family of BXD recombinant inbred (RI) mice derived from parental lines that encode for wildtype (C57BL/6J) and mutant (DBA/2J) Tyrp1. Protein levels of Tyrp1 were measured in whole eyes and isolated irides. Bioinformatics analyses were performed on the expression data along with our archived sequence data. Separate data sets were generated which were comprised of strains that harbor either wildtype or mutant Tyrp1 and each was mined individually to identify gene networks that covary significantly with each isoform of Tyrp1. Ontology trees and network graphs were generated to probe essential function and statistical significance of covariation. Genes with strong covariance in wildtype mice were assembled into genome-wide heatmaps for cohorts carrying either wildtype or mutant Tyrp1. RESULTS Single nucleotide polymorphism (SNP) analysis verified the presence of the Tyrp1b mutation in the Tyrp1 gene. Message levels were greater in BXD strains with the mutant Tyrp1. Interval mapping of these BXD mice revealed a strong expression quantitative trait locus (eQTL) on Chr 4 at the location of the gene itself. Composite mapping revealed a suggestive eQTL on Chr 9 at the location of myosin-Va (Myo5a), mutations in which are known as dilute. Enriched biologic processes associated with wildtype Tyrp1 included pigmentation, melanin biosynthetic process, and mesenchymal cell development, while associations with the mutant gene included categories of neural crest cell development, protein metabolic processes and glycoprotein metabolic processes. Genome-wide heatmaps revealed strong candidate cis-eQTLs on Chr 4 at Tyrp1 and on Chr 9 at Myo5a in all mice. In the wildtype data set, Tyrp1 was an upstream regulator of six pigmentation and two mesenchyme genes. In addition, five genes, including Tyrp1, were at least partially regulated by Myo5a. Analyses of the strains harboring the mutant gene revealed significant loss of correlation to traditional genes and gain of correlation to genes with little or no functional relationship. CONCLUSIONS These findings indicate that the Tyrp1(b) mutation modifies the pathways and gene networks in which Tyrp1 functions. Our results also indicate direct and indirect regulatory control of Tyrp1 and other pigmentation and mesenchymal genes by Myo5a. Lastly, we find that the mutations reduce the ability of Tyrp1 to regulate expression of other genes that participate in pigmentation metabolism.
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Affiliation(s)
- Hong Lu
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN,Department of Ophthalmology, Affiliated Hospital of Nantong University, Nantong, China
| | - Liyuan Li
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN
| | - Edmond R. Watson
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN
| | - Robert W. Williams
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN
| | - Eldon E. Geisert
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN,Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN
| | - Monica M. Jablonski
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN,Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN
| | - Lu Lu
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN,Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
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Zhang KH, Li Z, Lei J, Pang T, Xu B, Jiang WY, Li HY. Oculocutaneous Albinism Type 3 (OCA3): Analysis of Two Novel Mutations in TYRP1 Gene in Two Chinese Patients. Cell Biochem Biophys 2011; 61:523-9. [DOI: 10.1007/s12013-011-9234-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Gargiulo A, Testa F, Rossi S, Di Iorio V, Fecarotta S, de Berardinis T, Iovine A, Magli A, Signorini S, Fazzi E, Galantuomo MS, Fossarello M, Montefusco S, Ciccodicola A, Neri A, Macaluso C, Simonelli F, Surace EM. Molecular and clinical characterization of albinism in a large cohort of Italian patients. Invest Ophthalmol Vis Sci 2011; 52:1281-9. [PMID: 20861488 DOI: 10.1167/iovs.10-6091] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to identify the molecular basis of albinism in a large cohort of Italian patients showing typical ocular landmarks of the disease and to provide a full characterization of the clinical ophthalmic manifestations. METHODS DNA samples from 45 patients with ocular manifestations of albinism were analyzed by direct sequencing analysis of five genes responsible for albinism: TYR, P, TYRP1, SLC45A2 (MATP), and OA1. All patients studied showed a variable degree of skin and hair hypopigmentation. Eighteen patients with distinct mutations in each gene associated with OCA were evaluated by detailed ophthalmic analysis, optical coherence tomography (OCT), and fundus autofluorescence. RESULTS Disease-causing mutations were identified in more than 95% of analyzed patients with OCA (28/45 [62.2%] cases with two or more mutations; 15/45 [33.3%] cases with one mutation). Thirty-five different mutant alleles were identified of which 15 were novel. Mutations in TYR were the most frequent (73.3%), whereas mutations in P occurred more rarely (13.3%) than previously reported. Novel mutations were also identified in rare loci such as TYRP1 and MATP. Mutations in the OA1 gene were not detected. Clinical assessment revealed that patients with iris and macular pigmentation had significantly higher visual acuity than did severe hypopigmented phenotypes. CONCLUSIONS TYR gene mutations represent a relevant cause of oculocutaneous albinism in Italy, whereas mutations in P present a lower frequency than that found in other populations. Clinical analysis revealed that the severity of the ocular manifestations depends on the degree of retinal pigmentation.
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Abstract
Albinism is a group of disorders characterized principally by its ophthalmic features with or without systemic manifestations. Persons with albinism manifest a wide variety of phenotypes and limited number of genotypes. Modern molecular genetics has encouraged a new classification and understanding of the subtypes of these disorders. In addition to the ocular and systemic manifestations, ophthalmologists must be familiar with the specific visual needs and psychological challenges of these individuals as well as those of their families.
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Affiliation(s)
- Alex V Levin
- Wills Eye Institute, Pediatric Ophthalmology and Ocular Genetics, Philadelphia, Pennsylvania 19107, USA.
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