1
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Kuht HJ, Thomas MG, McLean RJ, Sheth V, Proudlock FA, Gottlob I. Abnormal foveal morphology in carriers of oculocutaneous albinism. Br J Ophthalmol 2023; 107:1202-1208. [PMID: 35379600 PMCID: PMC10359511 DOI: 10.1136/bjophthalmol-2020-318192] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 03/18/2022] [Indexed: 01/04/2023]
Abstract
BACKGROUND/AIMS To investigate the foveal morphology in carriers of oculocutaneous albinism (OCA) using spectral domain optical coherence tomography (SD-OCT). A cross-sectional, observational study. METHODS Handheld SD-OCT (Envisu C2300) was used to acquire horizontal scans through the centre of the fovea in biological parents of patients with OCA (n=28; mean age±SD=40.43±8.07 years) and age-matched and ethnicity-matched controls (n=28; mean age±SD=38.04±10.27 years). Sequence analysis was performed for variants in known genes associated with OCA. Best-corrected visual acuity (BCVA), presence of foveal hypoplasia and grade, foveal, parafoveal and perifoveal thickness measurements of total retinal layers (TRL), inner retinal layers (IRL) and outer retinal layers (ORL) thickness were measured. RESULTS Foveal hypoplasia was identified in 32.14% of OCA carriers; grade 1 in all cases. OCA carriers demonstrated significant thicker TRL thickness (median difference: 13.46 µm, p=0.009) and IRL thickness (mean difference: 8.98 µm, p<0.001) at the central fovea compared with controls. BCVA of carriers was between -0.16 and 0.18 logMAR (mean: 0.0 logMAR). No significant differences in BCVA was noted between OCA carriers or controls (p=0.83). In the OCA carriers, we identified previously reported pathogenic variants in TYR, OCA2 and SLC45A2, novel OCA2 variants (n=3) and heterozygosity of the pathogenic TYR haplotype. CONCLUSION We have, for the first time, identified foveal abnormalities in OCA carriers. This provides clinical value, particularly in cases where limited phenotype data are available. Our findings raise the possibility that previously reported mild cases of foveal hypoplasia or isolated foveal hypoplasia could correspond to OCA carrier status.
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Affiliation(s)
- Helen J Kuht
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Mervyn G Thomas
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Rebecca J McLean
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Viral Sheth
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Frank A Proudlock
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Irene Gottlob
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
- Cooper Medical School of Rowan University, Cooper Neurological Institute, Camden, New Jersey, USA
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2
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Tung D, McKay BS. Decoding Race and Age-Related Macular Degeneration: GPR 143 Activity Is the Key. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:43-47. [PMID: 37440012 DOI: 10.1007/978-3-031-27681-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible blindness in the developed world. Caucasians are eightfold more likely to develop AMD than any other race, indicating a racial bias in AMD incidence which is unexplained. We hypothesize that pigmentation of the retinal pigment epithelium (RPE) and choroid protects from AMD and underlies this peculiar racial bias. We investigated GPR143, a receptor in the pigmentation pathway, which is activated by a melanin synthesis by-product, l-dopa. In this model, greater pigmentation leads to greater l-dopa production and, in turn, greater GPR143 signaling. GPR143 activity upregulates PEDF and downregulates both VEGF and exosomes; all of which reduce the angiogenic potential in the retina. Moreover, we demonstrate that GPR143 signaling enhances the digestion of shed photoreceptor outer segments. Together, our data suggests a central role for GPR143 signaling in RPE-photoreceptor interaction which is critical to healthy vision.
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Affiliation(s)
- Dorothy Tung
- Department of Ophthalmology and Vision Science, University of Arizona, Tucson, AZ, USA
| | - Brian S McKay
- Department of Ophthalmology and Vision Science, University of Arizona, Tucson, AZ, USA.
- Department of Physiology, University of Arizona, Tucson, AZ, USA.
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3
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Garanto A, Ferreira CR, Boon CJF, van Karnebeek CDM, Blau N. Clinical and biochemical footprints of inherited metabolic disorders. VII. Ocular phenotypes. Mol Genet Metab 2022; 135:311-319. [PMID: 35227579 PMCID: PMC10518078 DOI: 10.1016/j.ymgme.2022.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/19/2022] [Accepted: 02/11/2022] [Indexed: 12/11/2022]
Abstract
Ocular manifestations are observed in approximately one third of all inherited metabolic disorders (IMDs). Although ocular involvement is not life-threatening, it can result in severe vision loss, thereby leading to an additional burden for the patient. Retinal degeneration with or without optic atrophy is the most frequent phenotype, followed by oculomotor problems, involvement of the cornea and lens, and refractive errors. These phenotypes can provide valuable clues that contribute to its diagnosis. In this issue we found 577 relevant IMDs leading to ophthalmologic manifestations. This article is the seventh of a series attempting to create and maintain a comprehensive list of clinical and metabolic differential diagnoses according to system involvement.
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Affiliation(s)
- Alejandro Garanto
- Department of Pediatrics, Amalia Children's Hospital Radboud Center for Mitochondrial and Metabolic Diseases, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Carlos R Ferreira
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands and Amsterdam University Medical Centers, Academic Medical Center, Department of Ophthalmology, University of Amsterdam, Amsterdam, the Netherlands.
| | - Clara D M van Karnebeek
- Department of Pediatrics, Amalia Children's Hospital Radboud Center for Mitochondrial and Metabolic Diseases, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Departments of Pediatrics and Human Genetics, Emma Children's Hospital, Amsterdam Reproduction and Development, Amsterdam University Medical Centers, Amsterdam, the Netherlands.
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital, Zürich, Switzerland.
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4
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Ma L, Zhu J, Wang J, Huang Y, Zhang J, Wang C, Zhou Y, Peng D. Genetic Analysis of 28 Chinese Families With Tyrosinase-Positive Oculocutaneous Albinism. Front Genet 2021; 12:715437. [PMID: 34707637 PMCID: PMC8544823 DOI: 10.3389/fgene.2021.715437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/30/2021] [Indexed: 11/28/2022] Open
Abstract
Background Tyrosinase-positive oculocutaneous albinism (OCA, type II, OCA2) is an autosomal recessive genetic disease in which the biosynthesis of melanin decreases in the skin, hair, and eyes. OCA2 disease is caused by mutations in OCA2 gene. The gene product plays a role in regulating the pH of melanosomes. Up to now, hundreds of OCA2 mutations have been reported and novel variants are still being discovered. Methods In this study, we reviewed the records of OCA2 patients who had conducted albinism genetic testing, and then analyzed the clinical and genetic information of 28 OCA2 patients who had been genetically diagnosed by using Sanger sequencing and next-generation sequencing. Results In this study, we reported 31 variants screened from 28 Chinese OCA2 families, and characterized the detailed molecular and clinical presentations. There were 12 novel variants among all detected variants, including 3 missense variants (p.G393V, p.T482A, and p.R720P), 4 frameshift variants (p.R53Gfs∗49, p.N279Kfs∗17, p.I469Lfs∗4, p.I655Nfs∗12), 2 splicing variants (c.1637-2A > G, c.1951 + 1G > C), 2 stopgain variants (p.L278X, p.W652X) and 1 insertion variants (p.P315LinsT). One potential cluster of missense variants was implicated indicating the important roles of the underlying domains in OCA2 pathogenesis. Conclusion Our results were beneficial for diagnosis and precision clinical management for OCA2-related disorder, and this study expanded the mutation spectrum of oculocutaneous albinism.
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Affiliation(s)
- Linya Ma
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jianjian Zhu
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jing Wang
- Changsha Kingmed Center for Clinical Laboratory, Changsha, China
| | - Yazhou Huang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jibo Zhang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Chao Wang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Yuan Zhou
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Dan Peng
- Department of Medical Genetics, Changde First People's Hospital, Changde, China.,Affiliated Hospital of Changde City, University of South China, Hengyang, China
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5
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Ramos AN, Ramos JGR, Fernandes JD. Prevalence of premalignant and malignant skin lesions in oculocutaneous albinism patients. ACTA ACUST UNITED AC 2021; 67:77-82. [PMID: 34161467 DOI: 10.1590/1806-9282.67.01.20200356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 08/30/2020] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Oculocutaneous albinism describes a group of pigmentary disorders that lead to skin sensitivity and predisposition to skin malignances. AIMS To analyze clinical and epidemiological data in oculocutaneous albinism patients and to determine the prevalence of malignant skin lesions, assessing possible risk factors for skin cancer. METHODS Cross-sectional study evaluating epidemiological data, habits of sun exposure and sun protection, and clinical examination of albino patients followed in a reference dermatology outpatient clinic in Brasil. Our primary outcome was the occurrence of malignant skin lesions in biopsied tissues. RESULTS Of 74 patients analyzed, 11 (15%) had one or more suspicious lesions and were biopsied, of which 8 (72.7%) patients presented with basal cell carcinomas, 7 (63.3%) presented with squamous cell carcinoma, and 1 (9%) presented with melanoma. Moreover, 32(43%) patients presented with actinic keratosis. Age, female gender, previous history of sunburn, history of malignant lesions and history of sun exposure without photoprotection were associated with the presence of malignant lesions. LIMITATIONS Unicentric, non-aleatory sample. CONCLUSIONS There was a high prevalence of malignant and pre-malignant lesions in this population. Some potentially modifiable risk factors were associated with the occurrence of malignant skin lesions.
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Affiliation(s)
- Andréia Nogueira Ramos
- Universidade Federal da Bahia, Programa de Pós-graduação em Ciências da Saúde - Salvador (BA), Brasil
| | | | - Juliana Dumet Fernandes
- Hospital Universitário Professor Edgard Santos, Departamento de Dermatologia - Salvador (BA), Brasil
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6
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Galarza JA. Comparative transcriptomics of albino and warningly-coloured caterpillars. Ecol Evol 2021; 11:7507-7517. [PMID: 34188830 PMCID: PMC8216890 DOI: 10.1002/ece3.7581] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 12/23/2022] Open
Abstract
Coloration is perhaps one of the most prominent adaptations for survival and reproduction of many taxa. Coloration is of particular importance for aposematic species, which rely on their coloring and patterning acting as a warning signal to deter predators. Most research has focused on the evolution of warning coloration by natural selection. However, little information is available for color mutants of aposematic species, particularly at the genomic level. Here, I compare the transcriptomes of albino mutant caterpillars of the aposematic wood tiger moth (Arctia plantaginis) to those of their full sibs having their distinctive orange-black warning coloration. The results showed >290 differentially expressed genes genome-wide. Genes involved in the immune system, structural constituents of cuticular, and immunity were mostly downregulated in the albino caterpillars. Surprisingly, higher expression was observed in core melanin genes from albino caterpillars, suggesting that melanin synthesis may be disrupted in terminal ends of the pathway during its final conversion. Taken together, these results suggest that caterpillar albinism may not be due to a depletion of melanin precursor genes. In contrast, the albino condition may result from the combination of faulty melanin conversion late in its synthesis and structural deficiencies in the cuticular preventing its deposition. The results are discussed in the context of how albinism may impact individuals of aposematic species in the wild.
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Affiliation(s)
- Juan A. Galarza
- Dpartment of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
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7
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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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8
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Volk AE, Hedergott A, Preising M, Rading S, Fricke J, Herkenrath P, Nürnberg P, Altmüller J, von Ameln S, Lorenz B, Neugebauer A, Karsak M, Kubisch C. Biallelic mutations in L-dopachrome tautomerase (DCT) cause infantile nystagmus and oculocutaneous albinism. Hum Genet 2021; 140:1157-1168. [PMID: 33959807 DOI: 10.1007/s00439-021-02285-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/19/2021] [Indexed: 11/26/2022]
Abstract
Infantile nystagmus syndrome (INS) denominates early-onset, involuntary oscillatory eye movements with different etiologies. Nystagmus is also one of the symptoms in oculocutaneus albinism (OCA), a heterogeneous disease mainly caused by defects in melanin synthesis or melanosome biogenesis. Dopachrome tautomerase (DCT, also called TYRP2) together with tyrosinase (TYR) and tyrosin-related protein 1 (TYRP1) is one of the key enzymes in melanin synthesis. Although DCT´s role in pigmentation has been proven in different species, until now only mutations in TYR and TYRP1 have been found in patients with OCA. Detailed ophthalmological and orthoptic investigations identified a consanguineous family with two individuals with isolated infantile nystagmus and one family member with subtle signs of albinism. By whole-exome sequencing and segregation analysis, we identified the missense mutation c.176G > T (p.Gly59Val) in DCT in a homozygous state in all three affected family members. We show that this mutation results in incomplete protein maturation and targeting in vitro compatible with a partial or total loss of function. Subsequent screening of a cohort of patients with OCA (n = 85) and INS (n = 25) revealed two heterozygous truncating mutations, namely c.876C > A (p.Tyr292*) and c.1407G > A (p.Trp469*), in an independent patient with OCA. Taken together, our data suggest that mutations in DCT can cause a phenotypic spectrum ranging from isolated infantile nystagmus to oculocutaneous albinism.
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Affiliation(s)
- Alexander E Volk
- Institute of Human Genetics, University Medical Center Hamburg Eppendorf (UKE), Martinistr. 52, 20246, Hamburg, Germany.
| | - Andrea Hedergott
- Department of Ophthalmology, Faculty of Medicine, University Hospital Cologne, 50931, Cologne, Germany
| | - Markus Preising
- Department of Ophthalmology, Justus-Liebig-University Giessen, 35392, Giessen, Germany
| | - Sebastian Rading
- Neuronal and Cellular Signal Transduction, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246, Hamburg, Germany
| | - Julia Fricke
- Department of Ophthalmology, Faculty of Medicine, University Hospital Cologne, 50931, Cologne, Germany
| | - Peter Herkenrath
- Department of Paediatrics, University of Cologne, 50931, Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, University of Cologne, 50931, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, 50931, Cologne, Germany
| | - Simon von Ameln
- Institute of Human Genetics, University of Ulm, 89081, Ulm, Germany
| | - Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig-University Giessen, 35392, Giessen, Germany
- Department of Ophthalmology, University Hospital of Bonn, 53127, Bonn, Germany
| | - Antje Neugebauer
- Department of Ophthalmology, Faculty of Medicine, University Hospital Cologne, 50931, Cologne, Germany
| | - Meliha Karsak
- Neuronal and Cellular Signal Transduction, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246, Hamburg, Germany
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg Eppendorf (UKE), Martinistr. 52, 20246, Hamburg, Germany
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9
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Gautron A, Migault M, Bachelot L, Corre S, Galibert MD, Gilot D. Human TYRP1: Two functions for a single gene? Pigment Cell Melanoma Res 2021; 34:836-852. [PMID: 33305505 DOI: 10.1111/pcmr.12951] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 11/12/2020] [Accepted: 12/01/2020] [Indexed: 01/07/2023]
Abstract
In the animal kingdom, skin pigmentation is highly variable between species, and it contributes to phenotypes. In humans, skin pigmentation plays a part in sun protection. Skin pigmentation depends on the ratio of the two pigments pheomelanin and eumelanin, both synthesized by a specialized cell population, the melanocytes. In this review, we explore one important factor in pigmentation: the tyrosinase-related protein 1 (TYRP1) gene which is involved in eumelanin synthesis via the TYRP1 protein. Counterintuitively, high TYRP1 mRNA expression is associated with a poor clinical outcome for patients with metastatic melanomas. Recently, we were able to explain this unexpected TYRP1 function by demonstrating that TYRP1 mRNA sequesters microRNA-16, a tumor suppressor miRNA. Here, we focus on actors influencing TYRP1 mRNA abundance, particularly transcription factors, single nucleotide polymorphisms (SNPs), and miRNAs, as they all dictate the indirect oncogenic activity of TYRP1.
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Affiliation(s)
- Arthur Gautron
- CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Univ. Rennes, Rennes, France
| | - Mélodie Migault
- CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Univ. Rennes, Rennes, France.,Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Laura Bachelot
- CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Univ. Rennes, Rennes, France
| | - Sébastien Corre
- CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Univ. Rennes, Rennes, France
| | - Marie-Dominique Galibert
- CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Univ. Rennes, Rennes, France.,CHU Rennes, Génétique Moléculaire et Génomique, UMR 6290, F-35000, Rennes, France
| | - David Gilot
- CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Univ. Rennes, Rennes, France.,INSERM U1242, Centre Eugène Marquis, Rennes, France
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10
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Seruggia D, Josa S, Fernández A, Montoliu L. The structure and function of the mouse tyrosinase locus. Pigment Cell Melanoma Res 2020; 34:212-221. [DOI: 10.1111/pcmr.12942] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/06/2020] [Accepted: 10/14/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Davide Seruggia
- Department of Molecular and Cellular Biology National Centre for Biotechnology (CNB‐CSIC) Madrid Madrid Spain
- CIBERER‐ISCIII Madrid Spain
- Division of Hematology/Oncology Boston Children's HospitalHarvard Medical School Boston MA USA
| | - Santiago Josa
- Department of Molecular and Cellular Biology National Centre for Biotechnology (CNB‐CSIC) Madrid Madrid Spain
- CIBERER‐ISCIII Madrid Spain
| | - Almudena Fernández
- Department of Molecular and Cellular Biology National Centre for Biotechnology (CNB‐CSIC) Madrid Madrid Spain
- CIBERER‐ISCIII Madrid Spain
| | - Lluis Montoliu
- Department of Molecular and Cellular Biology National Centre for Biotechnology (CNB‐CSIC) Madrid Madrid Spain
- CIBERER‐ISCIII Madrid Spain
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11
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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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12
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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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Rayner JE, Duffy DL, Smit DJ, Jagirdar K, Lee KJ, De’Ambrosis B, Smithers BM, McMeniman EK, McInerney-Leo AM, Schaider H, Stark MS, Soyer HP, Sturm RA. Germline and somatic albinism variants in amelanotic/hypomelanotic melanoma: Increased carriage of TYR and OCA2 variants. PLoS One 2020; 15:e0238529. [PMID: 32966289 PMCID: PMC7510969 DOI: 10.1371/journal.pone.0238529] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 08/18/2020] [Indexed: 12/30/2022] Open
Abstract
Amelanotic/hypomelanotic melanoma is a clinicopathologic subtype with absent or minimal melanin. This study assessed previously reported coding variants in albinism genes (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, LRMDA) and common intronic, regulatory variants of OCA2 in individuals with amelanotic/hypomelanotic melanoma, pigmented melanoma cases and controls. Exome sequencing was available for 28 individuals with amelanotic/hypomelanotic melanoma and 303 individuals with pigmented melanoma, which were compared to whole exome data from 1144 Australian controls. Microarray genotyping was available for a further 17 amelanotic/hypomelanotic melanoma, 86 pigmented melanoma, 147 melanoma cases (pigmentation unknown) and 652 unaffected controls. Rare deleterious variants in TYR/OCA1 were more common in amelanotic/hypomelanotic melanoma cases than pigmented melanoma cases (set mixed model association tests P = 0.0088). The OCA2 hypomorphic allele p.V443I was more common in melanoma cases (1.8%) than controls (1.0%, X2 P = 0.02), and more so in amelanotic/hypomelanotic melanoma (4.4%, X2 P = 0.007). No amelanotic/hypomelanotic melanoma cases carried an eye and skin darkening haplotype of OCA2 (including rs7174027), present in 7.1% of pigmented melanoma cases (P = 0.0005) and 9.4% controls. Variants in TYR and OCA2 may play a role in amelanotic/hypomelanotic melanoma susceptibility. We suggest that somatic loss of function at these loci could contribute to the loss of tumor pigmentation, consistent with this we found a higher rate of somatic mutation in TYR/OCA2 in amelanotic/hypomelanotic melanoma vs pigmented melanoma samples (28.6% vs 3.0%; P = 0.021) from The Cancer Genome Atlas Skin Cutaneous Melanoma collection.
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Affiliation(s)
- Jenna E. Rayner
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
| | - David L. Duffy
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Qld, Australia
| | - Darren J. Smit
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Kasturee Jagirdar
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Katie J. Lee
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Brian De’Ambrosis
- Dermatology Department, Princess Alexandra Hospital, Brisbane, Qld, Australia
- Faculty of Medicine, The University of Queensland, Brisbane, Qld, Australia
- South East Dermatology, Annerley, Brisbane, Qld, Australia
| | - B. Mark Smithers
- Queensland Melanoma Project, School of Medicine, The University of Queensland, Brisbane, Qld, Australia
| | - Erin K. McMeniman
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
- Dermatology Department, Princess Alexandra Hospital, Brisbane, Qld, Australia
| | - Aideen M. McInerney-Leo
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Helmut Schaider
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Mitchell S. Stark
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
| | - H. Peter Soyer
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
- Dermatology Department, Princess Alexandra Hospital, Brisbane, Qld, Australia
| | - Richard A. Sturm
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Qld, Australia
- * E-mail:
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14
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Bi Q, Shen L, Evans R, Zhang Z, Wang S, Dai W, Liu C. Determining the Topic Evolution and Sentiment Polarity for Albinism in a Chinese Online Health Community: Machine Learning and Social Network Analysis. JMIR Med Inform 2020; 8:e17813. [PMID: 32469320 PMCID: PMC7293058 DOI: 10.2196/17813] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/05/2020] [Accepted: 03/23/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND There are more than 6000 rare diseases in existence today, with the number of patients with these conditions rapidly increasing. Most research to date has focused on the diagnosis, treatment, and development of orphan drugs, while few studies have examined the topics and emotions expressed by patients living with rare diseases on social media platforms, especially in online health communities (OHCs). OBJECTIVE This study aimed to determine the topic categorizations and sentiment polarity for albinism in a Chinese OHC, Baidu Tieba, using multiple methods. The OHC was deeply mined using topic mining, social network analysis, and sentiment polarity analysis. Through these methods, we determined the current situation of community construction, identifying the ongoing needs and problems experienced by people with albinism in their daily lives. METHODS We used the albinism community on the Baidu Tieba platform as the data source in this study. Term frequency-inverse document frequency, latent dirichlet allocation models, and naive Bayes were employed to mine the various topic categories. Social network analysis, which was completed using the Gephi tool, was employed to analyze the evolution of the albinism community. Sentiment polarity analysis was performed using a long short-term memory algorithm. RESULTS We identified 8 main topics discussed in the community: daily sharing, family, interpersonal communication, social life and security, medical care, occupation and education, beauty, and self-care. Among these topics, daily sharing represented the largest proportion of the discussions. From 2012 to 2019, the average degree and clustering coefficient of the albinism community continued to decline, while the network center transferred from core communities to core users. A total of 68.43% of the corpus was emotional, with 35.88% being positive and 32.55% negative. There were statistically significant differences in the distribution of sentiment polarity between topics (P<.001). Negative emotions were twice as high as positive emotions in the social life and security topic. CONCLUSIONS The study reveals insights into the emotions expressed by people with albinism in the Chinese OHC, Baidu Tieba, providing health care practitioners with greater appreciation of the current emotional support needed by patients and the patient experience. Current OHCs do not exert enough influence due to limited effective organization and development. Health care sectors should take greater advantage of OHCs to support vulnerable patients with rare diseases to meet their evidence-based needs.
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Affiliation(s)
- Qiqing Bi
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
- Hubei Provincial Research Center for Health Technology Assessment, Wuhan, China
- Institute of Smart Health, Huazhong University of Science & Technology, Wuhan, China
| | - Lining Shen
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
- Hubei Provincial Research Center for Health Technology Assessment, Wuhan, China
- Institute of Smart Health, Huazhong University of Science & Technology, Wuhan, China
| | - Richard Evans
- College of Engineering, Design and Physical Sciences, Brunel University London, London, United Kingdom
| | - Zhiguo Zhang
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
- Hubei Provincial Research Center for Health Technology Assessment, Wuhan, China
| | - Shimin Wang
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
- Hubei Provincial Research Center for Health Technology Assessment, Wuhan, China
| | - Wei Dai
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Cui Liu
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
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15
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de Groot T, Meurs P, Jacquet W. The Effect of Contact Interventions on the Stigma of People with Albinism in Tanzania. JOURNAL OF VISUAL IMPAIRMENT & BLINDNESS 2019. [DOI: 10.1177/0145482x19874188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Tjitske de Groot
- Department of Educational Sciences EDWE-LOCI, Faculty of Psychology and Educational Sciences, Vrije Universiteit Brussel, Brussel, Belgium
| | - Pieter Meurs
- Department of Educational Sciences EDWE-LOCI, Faculty of Psychology and Educational Sciences, Vrije Universiteit Brussel, Brussel, Belgium
| | - Wolfgang Jacquet
- Department of Educational Sciences EDWE-LOCI, Faculty of Psychology and Educational Sciences, Vrije Universiteit Brussel, Brussel, Belgium
- Department of Periodontology and Oral Implantology, Dental School, Faculty of Medicine and Health Sciences, University of Ghent, Ghent, Belgium
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16
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Karlén E, Milestad L, Pansell T. Accommodation and near visual function in children with albinism. Acta Ophthalmol 2019; 97:608-615. [PMID: 30702212 DOI: 10.1111/aos.14040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 01/09/2019] [Indexed: 12/30/2022]
Abstract
PURPOSE Albinism degrades visual function due to developmental disorders of the eye and visual pathways, larger refractive errors, absent binocularity and poor fixation control. Reading spectacles is commonly prescribed in our clinic and well tolerated. The purpose was to evaluate whether the accommodative response is typical or affected in comparison to a reference group. METHODS Twenty-two children with albinism (median: 13.5 years) and 12 controls (median: 13 years) underwent a full optometric examination and an objective accommodation measurement (WAM-5500 @ 6 Hz; Grand Seiko) in response to minus-lens-blur (-1, -2 and -3 D) and to a prolonged near viewing task (20 cm) for 5 min. RESULTS Children with albinism displayed less accommodation to minus lens-blur and during sustained near viewing (p < 0.001) compared to the reference group. Higher visual acuity correlates with a better accommodative response (r ≥ 0.5; p ≤ 0.04). The subjective and objective measures of accommodation did not correlate. The habitual reading distance was always closer than the point towards which the subjects with albinism seemed to accommodate according to the measurements at 20 cm. CONCLUSION Children with albinism benefits from reading spectacles due to a combination of close habitual reading distance and a poor accommodation. Objective recording of accommodation is not critical for a correct judgement of near visual function. Children already wearing reading spectacles were those with least accommodative response.
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Affiliation(s)
- Eva Karlén
- Children and Youth Team of Stockholm Low Vision Centre StockholmSweden
| | - Lollo Milestad
- Children and Youth Team of Stockholm Low Vision Centre StockholmSweden
| | - Tony Pansell
- St. Erik Eye Hospital Stockholm Sweden
- Department of Clinical Neuroscience Division of Ophthalmology and Vision Karolinska Institutet Stockholm Sweden
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17
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Fufa TD, Baxter LL, Wedel JC, Gildea DE, Loftus SK, Pavan WJ. MEK inhibition remodels the active chromatin landscape and induces SOX10 genomic recruitment in BRAF(V600E) mutant melanoma cells. Epigenetics Chromatin 2019; 12:50. [PMID: 31399133 PMCID: PMC6688322 DOI: 10.1186/s13072-019-0297-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/28/2019] [Indexed: 01/03/2023] Open
Abstract
Background The MAPK/ERK signaling pathway is an essential regulator of numerous cell processes that are crucial for normal development as well as cancer progression. While much is known regarding MAPK/ERK signal conveyance from the cell membrane to the nucleus, the transcriptional and epigenetic mechanisms that govern gene expression downstream of MAPK signaling are not fully elucidated. Results This study employed an integrated epigenome analysis approach to interrogate the effects of MAPK/ERK pathway inhibition on the global transcriptome, the active chromatin landscape, and protein–DNA interactions in 501mel melanoma cells. Treatment of these cells with the small-molecule MEK inhibitor AZD6244 induces hyperpigmentation, widespread gene expression changes including alteration of genes linked to pigmentation, and extensive epigenomic reprogramming of transcriptionally distinct regulatory regions associated with the active chromatin mark H3K27ac. Regulatory regions with differentially acetylated H3K27ac regions following AZD6244 treatment are enriched in transcription factor binding motifs of ETV/ETS and ATF family members as well as the lineage-determining factors MITF and SOX10. H3K27ac-dense enhancer clusters known as super-enhancers show similar transcription factor motif enrichment, and furthermore, these super-enhancers are associated with genes encoding MITF, SOX10, and ETV/ETS proteins. Along with genome-wide resetting of the active enhancer landscape, MEK inhibition also results in widespread SOX10 recruitment throughout the genome, including increased SOX10 binding density at H3K27ac-marked enhancers. Importantly, these MEK inhibitor-responsive enhancers marked by H3K27ac and occupied by SOX10 are located near melanocyte lineage-specific and pigmentation genes and overlap numerous human SNPs associated with pigmentation and melanoma phenotypes, highlighting the variants located within these regions for prioritization in future studies. Conclusions These results reveal the epigenetic reprogramming underlying the re-activation of melanocyte pigmentation and developmental transcriptional programs in 501mel cells in response to MEK inhibition and suggest extensive involvement of a MEK-SOX10 axis in the regulation of these processes. The dynamic chromatin changes identified here provide a rich genomic resource for further analyses of the molecular mechanisms governing the MAPK pathway in pigmentation- and melanocyte-associated diseases. Electronic supplementary material The online version of this article (10.1186/s13072-019-0297-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Temesgen D Fufa
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA.,Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Laura L Baxter
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Julia C Wedel
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Derek E Gildea
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | | | - Stacie K Loftus
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - William J Pavan
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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18
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Singh BK, Kim EK. P-Protein: A Novel Target for Skin-whitening Agent. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-018-0241-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Ramos AN, Fraga‐Braghiroli N, Ramos JGR, Scope A, Fernandes JD. Dermoscopy of naevi in patients with oculocutaneous albinism. Clin Exp Dermatol 2019; 44:e196-e199. [DOI: 10.1111/ced.13903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2018] [Indexed: 12/21/2022]
Affiliation(s)
- A. N. Ramos
- Medicine and Health Science Postgraduate Program Federal University of Bahia Bahia Brazil
- Dermatology Department Hospital São Rafael Salvador Brazil
| | - N. Fraga‐Braghiroli
- Dermatology Department, Skin and Cancer Associates Plantation Plantation FL USA
| | | | - A. Scope
- Medical Screening Institute Sheba Medical Center and Sackler Faculty of Medicine Tel Aviv University Tel Aviv Israel
- Dermatology Service Memorial Sloan‐Kettering Cancer Center New York NY USA
| | - J. D. Fernandes
- Dermatology Department Hospital Universitario Professor Edgard Santos Federal University of Bahia Bahia Brazil
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20
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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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21
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Kruijt CC, de Wit GC, Bergen AA, Florijn RJ, Schalij-Delfos NE, van Genderen MM. The Phenotypic Spectrum of Albinism. Ophthalmology 2018; 125:1953-1960. [DOI: 10.1016/j.ophtha.2018.08.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 11/28/2022] Open
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22
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Morice-Picard F, Taïeb C, Marti A, Gliksohn A, Bennani M, Bodemer C, Ezzedine K. Burden of albinism: development and validation of a burden assessment tool. Orphanet J Rare Dis 2018; 13:162. [PMID: 30227882 PMCID: PMC6145119 DOI: 10.1186/s13023-018-0894-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 08/20/2018] [Indexed: 11/22/2022] Open
Abstract
Background Albinism comprises a group of autosomal recessive diseases that are characterized by poor vision and a variable hypopigmentation phenotype. A comprehensive literature review showed that no tool can assess the burden experienced by individuals who present with albinism, although such a tool is needed and would be beneficial for clinicians and patients alike. Method The questionnaire was devised using standardized methodology for developing and validating questionnaires on the quality of life of subjects according to the following chronological structure: conceptual phase, development phase, and then validation phase. A multidisciplinary working group was assembled, including experts on questionnaire design and development, dermatologists specializing in care for patients with albinism, and representatives of the Genespoir association. Results Based on an initial verbatim report, the workgroup compiled a list of items that were transcribed and reformulated into questions. During the validation phase, principal component analysis (PCA) was conducted on the 24 items, which allowed the questionnaire to be reduced to 20 questions [Q]. The standardized regression coefficients were all greater than 0.5 for their corresponding factors. Based on their normalized regression coefficients, each group of questions was linked to one of the following four dimensions, with each dimension consisting of at least three questions: “Live with” (8 Q), “Daily life” (3 Q), “Resignation” (3 Q), and “Fear of the future” (6 Q). All dimensions correlated well with the overall BoA score. Cronbach’s α was 0.92 for the entire BoA scale, confirming excellent internal coherence. Intradimensional coherences all demonstrated excellent reliability (α > 0.65). The BoA questionnaire was highly correlated with the SF12, RSES and DLQI validated questionnaires. This outcome confirmed the external validity. Conclusion This questionnaire represents the first specific assessment tool for evaluating the burden of albinism. It is easy to use and relatively quick to complete, which will allow the burden to be evaluated over time with a reproducible questionnaire. To ensure that this questionnaire can be used by as many people as possible, cultural and linguistic validation in US English was conducted with the original French version. Electronic supplementary material The online version of this article (10.1186/s13023-018-0894-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Charles Taïeb
- FIMARAD, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | | | | | | | - Christine Bodemer
- MAGEC, CHU Necker-Enfants Malades, APHP, Paris, France.,Annimatrice, FIMARAD, Hôpital Necker-Enfants Malades, APHP, Paris, France
| | - Khaled Ezzedine
- EA EpiDermE, UPE-Université Paris-Est, Créteil, France.,CHU H Mondor, APHP, Créteil, France
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23
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Okamura K, Hayashi M, Nakajima O, Kono M, Abe Y, Hozumi Y, Suzuki T. A 4‐bp deletion promoter variant (rs984225803) is associated with mild
OCA
4 among Japanese patients. Pigment Cell Melanoma Res 2018; 32:79-84. [DOI: 10.1111/pcmr.12727] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 06/11/2018] [Accepted: 07/13/2018] [Indexed: 01/04/2023]
Affiliation(s)
- Ken Okamura
- Department of DermatologyFaculty of MedicineYamagata University Yamagata Japan
| | - Masahiro Hayashi
- Department of DermatologyFaculty of MedicineYamagata University Yamagata Japan
| | - Osamu Nakajima
- Faculty of MedicineResearch Center for Molecular GeneticsInstitute for Promotion of Medical Science ResearchYamagata University Yamagata Japan
| | - Michihiro Kono
- Department of DermatologyNagoya University Graduate School of Medicine Nagoya Japan
| | - Yuko Abe
- Department of DermatologyFaculty of MedicineYamagata University Yamagata Japan
| | - Yutaka Hozumi
- Department of DermatologyFaculty of MedicineYamagata University Yamagata Japan
| | - Tamio Suzuki
- Department of DermatologyFaculty of MedicineYamagata University Yamagata Japan
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24
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Caduff M, Bauer A, Jagannathan V, Leeb T. OCA2 splice site variant in German Spitz dogs with oculocutaneous albinism. PLoS One 2017; 12:e0185944. [PMID: 28973042 PMCID: PMC5626509 DOI: 10.1371/journal.pone.0185944] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/21/2017] [Indexed: 11/19/2022] Open
Abstract
We investigated a German Spitz family where the mating of a black male to a white female had yielded three puppies with an unexpected light brown coat color, lightly pigmented lips and noses, and blue eyes. Combined linkage and homozygosity analysis based on a fully penetrant monogenic autosomal recessive mode of inheritance identified a critical interval of 15 Mb on chromosome 3. We obtained whole genome sequence data from one affected dog, three wolves, and 188 control dogs. Filtering for private variants revealed a single variant with predicted high impact in the critical interval in LOC100855460 (XM_005618224.1:c.377+2T>G LT844587.1:c.-45+2T>G). The variant perfectly co-segregated with the phenotype in the family. We genotyped 181 control dogs with normal pigmentation from diverse breeds including 22 unrelated German Spitz dogs, which were all homozygous wildtype. Comparative sequence analyses revealed that LOC100855460 actually represents the 5'-end of the canine OCA2 gene. The CanFam 3.1 reference genome assembly is incorrect and separates the first two exons from the remaining exons of the OCA2 gene. We amplified a canine OCA2 cDNA fragment by RT-PCR and determined the correct full-length mRNA sequence (LT844587.1). Variants in the OCA2 gene cause oculocutaneous albinism type 2 (OCA2) in humans, pink-eyed dilution in mice, and similar phenotypes in corn snakes, medaka and Mexican cave tetra fish. We therefore conclude that the observed oculocutaneous albinism in German Spitz is most likely caused by the identified variant in the 5'-splice site of the first intron of the canine OCA2 gene.
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Affiliation(s)
- Madleina Caduff
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
| | - Anina Bauer
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- DermFocus, University of Bern, Bern, Switzerland
- * E-mail:
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25
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Fábos B, Farkas K, Tóth L, Sulák A, Tripolszki K, Tihanyi M, Németh R, Vas K, Csoma Z, Kemény L, Széll M, Nagy N. Delineating the genetic heterogeneity of OCA in Hungarian patients. Eur J Med Res 2017. [PMID: 28629449 PMCID: PMC5477306 DOI: 10.1186/s40001-017-0262-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a clinically and genetically heterogenic group of pigmentation abnormalities characterized by variable hair, skin, and ocular hypopigmentation. Six known genes and a locus on human chromosome 4q24 have been implicated in the etiology of isolated OCA forms (OCA 1-7). METHODS The most frequent OCA types among Caucasians are OCA1, OCA2, and OCA4. We aimed to investigate genes responsible for the development of these OCA forms in Hungarian OCA patients (n = 13). Mutation screening and polymorphism analysis were performed by direct sequencing on TYR, OCA2, SLC45A2 genes. RESULTS Although the clinical features of the investigated Hungarian OCA patients were identical, the molecular genetic data suggested OCA1 subtype in eight cases and OCA4 subtype in two cases. The molecular diagnosis was not clearly identifiable in three cases. In four patients, two different heterozygous known pathogenic or predicted to be pathogenic mutations were present. Seven patients had only one pathogenic mutation, which was associated with non-pathogenic variants in six cases. In two patients no pathogenic mutation was identified. CONCLUSIONS Our results suggest that the concomitant screening of the non-pathogenic variants-which alone do not cause the development of OCA, but might have clinical significance in association with a pathogenic variant-is important. Our results also show significant variation in the disease spectrum compared to other populations. These data also confirm that the concomitant analysis of OCA genes is critical, providing new insights to the phenotypic diversity of OCA and expanding the mutation spectrum of OCA genes in Hungarian patients.
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Affiliation(s)
- Beáta Fábos
- Mór Kaposi Teaching Hospital of the Somogy County, Kaposvár, Hungary
| | - Katalin Farkas
- MTA-SZTE Dermatological Research Group, University of Szeged, Szeged, Hungary
| | - Lola Tóth
- Department of Medical Genetics, University of Szeged, 4 Somogyi Bela Street, 6720, Szeged, Hungary
| | - Adrienn Sulák
- Department of Medical Genetics, University of Szeged, 4 Somogyi Bela Street, 6720, Szeged, Hungary
| | - Kornélia Tripolszki
- Department of Medical Genetics, University of Szeged, 4 Somogyi Bela Street, 6720, Szeged, Hungary
| | - Mariann Tihanyi
- Genetic Laboratory, Hospital of Zala County, Zalaegerszeg, Hungary
| | - Réka Németh
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Krisztina Vas
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Zsanett Csoma
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Lajos Kemény
- MTA-SZTE Dermatological Research Group, University of Szeged, Szeged, Hungary.,Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Márta Széll
- MTA-SZTE Dermatological Research Group, University of Szeged, Szeged, Hungary.,Department of Medical Genetics, University of Szeged, 4 Somogyi Bela Street, 6720, Szeged, Hungary
| | - Nikoletta Nagy
- MTA-SZTE Dermatological Research Group, University of Szeged, Szeged, Hungary. .,Department of Medical Genetics, University of Szeged, 4 Somogyi Bela Street, 6720, Szeged, Hungary. .,Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary.
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Galante Rocha de Vasconcelos FT, Hauzman E, Dutra Henriques L, Kilpp Goulart PR, de Faria Galvão O, Sano RY, da Silva Souza G, Lynch Alfaro J, de Lima Silveira LC, Fix Ventura D, Oliveira Bonci DM. A novel nonsense mutation in the tyrosinase gene is related to the albinism in a capuchin monkey (Sapajus apella). BMC Genet 2017; 18:39. [PMID: 28476152 PMCID: PMC5420114 DOI: 10.1186/s12863-017-0504-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 04/12/2017] [Indexed: 11/27/2022] Open
Abstract
Background Oculocutaneous Albinism (OCA) is an autosomal recessive inherited condition that affects the pigmentation of eyes, hair and skin. The OCA phenotype may be caused by mutations in the tyrosinase gene (TYR), which expresses the tyrosinase enzyme and has an important role in the synthesis of melanin pigment. The aim of this study was to identify the genetic mutation responsible for the albinism in a captive capuchin monkey, and to describe the TYR gene of normal phenotype individuals. In addition, we identified the subject’s species. Results A homozygous nonsense mutation was identified in exon 1 of the TYR gene, with the substitution of a cytosine for a thymine nucleotide (C64T) at codon 22, leading to a premature stop codon (R22X) in the albino robust capuchin monkey. The albino and five non-albino robust capuchin monkeys were identified as Sapajus apella, based on phylogenetic analyses, pelage pattern and geographic provenance. One individual was identified as S. macrocephalus. Conclusion We conclude that the point mutation C64T in the TYR gene is responsible for the OCA1 albino phenotype in the capuchin monkey, classified as Sapajus apella. Electronic supplementary material The online version of this article (doi:10.1186/s12863-017-0504-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Felipe Tadeu Galante Rocha de Vasconcelos
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Av. Professor Mello Moraes 1721 Bloco A Sala D9 - Butantã, São Paulo, SP, Brazil, 05508-030
| | - Einat Hauzman
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Av. Professor Mello Moraes 1721 Bloco A Sala D9 - Butantã, São Paulo, SP, Brazil, 05508-030.,Instituto Israelita de Ensino e Pesquisa Albert Einstein, Hospital Israelita Albert Einstein, São Paulo, São Paulo, Brazil
| | - Leonardo Dutra Henriques
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Av. Professor Mello Moraes 1721 Bloco A Sala D9 - Butantã, São Paulo, SP, Brazil, 05508-030
| | - Paulo Roney Kilpp Goulart
- Núcleo de Teoria e Pesquisa do Comportamento, Universidade Federal do Pará, Rua Augusto Corrêa, 01 - Guamá, Belém, PA, Brazil, 66075-110
| | - Olavo de Faria Galvão
- Núcleo de Teoria e Pesquisa do Comportamento, Universidade Federal do Pará, Rua Augusto Corrêa, 01 - Guamá, Belém, PA, Brazil, 66075-110
| | - Ronaldo Yuiti Sano
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Av. Professor Mello Moraes 1721 Bloco A Sala D9 - Butantã, São Paulo, SP, Brazil, 05508-030.,Departamento de Oftalmologia, Santa Casa de Misericórdia de São Paulo, São Paulo, São Paulo, Brazil
| | - Givago da Silva Souza
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Corrêa, 01 - Guamá, Belém, PA, Brazil, 66075-110.,Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Jessica Lynch Alfaro
- Institute for Society and Genetics, University of California Los Angeles, Box 957221, 3360 LSB, Los Angeles, CA, USA, 90095-7221.,Department of Anthropology, University of California Los Angeles, Los Angeles, CA, USA
| | - Luis Carlos de Lima Silveira
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Corrêa, 01 - Guamá, Belém, PA, Brazil, 66075-110.,Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Dora Fix Ventura
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Av. Professor Mello Moraes 1721 Bloco A Sala D9 - Butantã, São Paulo, SP, Brazil, 05508-030.,Instituto Israelita de Ensino e Pesquisa Albert Einstein, Hospital Israelita Albert Einstein, São Paulo, São Paulo, Brazil
| | - Daniela Maria Oliveira Bonci
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Av. Professor Mello Moraes 1721 Bloco A Sala D9 - Butantã, São Paulo, SP, Brazil, 05508-030. .,Instituto Israelita de Ensino e Pesquisa Albert Einstein, Hospital Israelita Albert Einstein, São Paulo, São Paulo, Brazil.
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Andres O, Wiegering V, König EM, Schneider AL, Semeniak D, Stritt S, Klopocki E, Schulze H. A novel two-nucleotide deletion in HPS6 affects mepacrine uptake and platelet dense granule secretion in a family with Hermansky-Pudlak syndrome. Pediatr Blood Cancer 2017; 64. [PMID: 27917594 DOI: 10.1002/pbc.26320] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 08/29/2016] [Accepted: 09/20/2016] [Indexed: 01/24/2023]
Abstract
BACKGROUND Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disease characterized by oculocutaneous albinism and platelet dysfunction. We report on a novel HPS6 homozygous frameshift variant (c.1919_1920delTC; p.Val640Glyfs*29) in a nonconsanguineous Caucasian family with two affected siblings (index patients) who presented with oculocutaneous albinism at birth and a mild bleeding phenotype during childhood and adolescence. PROCEDURE Genetic analysis was conducted by panel-based next-generation sequencing (NGS) and Sanger sequencing. Platelets of the index patients, their parents, and the unaffected sister were then comprehensively evaluated by luminoaggregometry, whole blood flow cytometry, immunoblotting, immunofluorescence, and transmission electron microscopy. RESULTS The homozygous frameshift variant in HPS6 gene detected by panel-based NGS and its segregation in the family was confirmed by Sanger sequencing. Flow cytometric analysis of the patients' platelets revealed a substantially decreased mepacrine uptake and release upon activation with a thrombin receptor agonist. Electron microscopy of resting platelets confirmed diminished dense granule content and enhanced vacuolization. Reduced release of adenosine triphosphate and CD63 neoexposition upon activation indicated not only a lack of dense granule content, but even an impairment of dense granule release. CONCLUSIONS Our results demonstrate that the novel loss-of-function variant in the HPS6 subunit of biogenesis of lysosome-related organelles complex 2 is pathologic and leads to a reduced platelet dense granules and their release. The findings are compatible with an impaired platelet function and hence an enhanced bleeding risk. In future, a valid genotype-phenotype correlation may translate into best supportive care, especially regarding elective surgery or trauma management.
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Affiliation(s)
- Oliver Andres
- University Children's Hospital Würzburg, University of Würzburg, Germany
| | - Verena Wiegering
- University Children's Hospital Würzburg, University of Würzburg, Germany
| | - Eva-Maria König
- Institute of Human Genetics, Biocentre, University of Würzburg, Germany
| | | | - Daniela Semeniak
- Institute of Experimental Biomedicine I, University Hospital Würzburg, Germany
| | - Simon Stritt
- Institute of Experimental Biomedicine I, University Hospital Würzburg, Germany
| | - Eva Klopocki
- Institute of Human Genetics, Biocentre, University of Würzburg, Germany
| | - Harald Schulze
- Institute of Experimental Biomedicine I, University Hospital Würzburg, Germany
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Identification of two novel mutations in the SLC45A2 gene in a Hungarian pedigree affected by unusual OCA type 4. BMC MEDICAL GENETICS 2017; 18:27. [PMID: 28298193 PMCID: PMC5353789 DOI: 10.1186/s12881-017-0386-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 03/01/2017] [Indexed: 11/12/2022]
Abstract
Background Oculocutaneous albinism (OCA) is a clinically and genetically heterogenic group of pigmentation abnormalities. OCA type IV (OCA4, OMIM 606574) develops due to homozygous or compound heterozygous mutations in the solute carrier family 45, member 2 (SLC45A2) gene. This gene encodes a membrane-associated transport protein, which regulates tyrosinase activity and, thus, melanin content by changing melanosomal pH and disrupting the incorporation of copper into tyrosinase. Methods Here we report two Hungarian siblings affected by an unusual OCA4 phenotype. After genomic DNA was isolated from peripheral blood of the patients, the coding regions of the SLC45A2 gene were sequenced. In silico tools were applied to identify the functional impact of the newly detected mutations. Results Direct sequencing of the SLC45A2 gene revealed two novel, heterozygous mutations, one missense (c.1226G > A, p.Gly409Asp) and one nonsense (c.1459C > T, p.Gln437*), which were present in both patients, suggesting the mutations were compound heterozygous. In silico tools suggest that these variations are disease causing mutations. Conclusions The newly identified mutations may affect the transmembrane domains of the protein, and could impair transport function, resulting in decreases in both melanosomal pH and tyrosinase activity. Our study provides expands on the mutation spectrum of the SLC45A2 gene and the genetic background of OCA4.
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Grigorian A, McKetton L, Schneider KA. Measuring Connectivity in the Primary Visual Pathway in Human Albinism Using Diffusion Tensor Imaging and Tractography. J Vis Exp 2016. [PMID: 27585189 DOI: 10.3791/53759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In albinism, the number of ipsilaterally projecting retinal ganglion cells (RGCs) is significantly reduced. The retina and optic chiasm have been proposed as candidate sites for misrouting. Since a correlation between the number of lateral geniculate nucleus (LGN) relay neurons and LGN size has been shown, and based on previously reported reductions in LGN volumes in human albinism, we suggest that fiber projections from LGN to the primary visual cortex (V1) are also reduced. Studying structural differences in the visual system of albinism can improve the understanding of the mechanism of misrouting and subsequent clinical applications. Diffusion data and tractography are useful for mapping the OR (optic radiation). This manuscript describes two algorithms for OR reconstruction in order to compare brain connectivity in albinism and controls.An MRI scanner with a 32-channel head coil was used to acquire structural scans. A T1-weighted 3D-MPRAGE sequence with 1 mm(3) isotropic voxel size was used to generate high-resolution images for V1 segmentation. Multiple proton density (PD) weighted images were acquired coronally for right and left LGN localization. Diffusion tensor imaging (DTI) scans were acquired with 64 diffusion directions. Both deterministic and probabilistic tracking methods were run and compared, with LGN as the seed mask and V1 as the target mask. Though DTI provides relatively poor spatial resolution, and accurate delineation of OR may be challenging due to its low fiber density, tractography has been shown to be advantageous both in research and clinically. Tract based spatial statistics (TBSS) revealed areas of significantly reduced white matter integrity within the OR in patients with albinism compared to controls. Pairwise comparisons revealed a significant reduction in LGN to V1 connectivity in albinism compared to controls. Comparing both tracking algorithms revealed common findings, strengthening the reliability of the technique.
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Affiliation(s)
- Anahit Grigorian
- Department of Biology, Centre for Vision Research, York University;
| | - Larissa McKetton
- Department of Biology, Centre for Vision Research, York University
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Chen Y, Pan L, Su Z, Wang J, Li H, Ma X, Liu Y, Lu F, Qu J, Hou L. The transcription factor TBX2 regulates melanogenesis in melanocytes by repressing Oca2. Mol Cell Biochem 2016; 415:103-9. [DOI: 10.1007/s11010-016-2680-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/04/2016] [Indexed: 01/24/2023]
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Aluko-Olokun B, Olaitan AA, Morgan RE, Oginni FO, Aluko-Olokun OA, Ibukun-Obaro O, Adenaike FS, Alade MO. Is there an association between African national HIV prevalence values and socio-economic status of their albino populations? HIV & AIDS REVIEW 2016. [DOI: 10.1016/j.hivar.2016.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Mohammad S, Gottlob I, Sheth V, Pilat A, Lee H, Pollheimer E, Proudlock FA. Characterization of Abnormal Optic Nerve Head Morphology in Albinism Using Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2015. [PMID: 26200501 DOI: 10.1167/iovs.15-16856] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To characterize abnormalities in three-dimensional optic nerve head (ONH) morphology in people with albinism (PWA) using spectral-domain optical coherence tomography (SD-OCT) and to determine whether ONH abnormalities relate to other retinal and clinical abnormalities. METHODS Spectral-domain OCT was used to obtain three-dimensional images from 56 PWA and 60 age- and sex-matched control subjects. B-scans were corrected for nystagmus-associated motion artefacts. Disc, cup, and rim ONH dimensions and peripapillary retinal nerve fiber layer (ppRNFL) thickness were calculated using Copernicus and ImageJ software. RESULTS Median disc areas were similar in PWA (median = 1.65 mm2) and controls (1.71 mm2, P = 0.128), although discs were significantly elongated horizontally in PWA (P < 0.001). In contrast, median optic cup area in PWA (0.088 mm2) was 23.7% of that in controls (0.373 mm2, P < 0.001), with 39.4% of eyes in PWA not demonstrating a measurable optic cup. This led to significantly smaller cup to disc ratios in PWA (P < 0.001). Median rim volume in PWA (0.273 mm3) was 136.6% of that in controls (0.200 mm3). The ppRNFL was significantly thinner in PWA compared with controls (P < 0.001), especially in the temporal quadrant. In PWA, ppRNFL thickness was correlated to ganglion cell thickness at the central fovea (P = 0.007). Several ONH abnormalities, such as cup to disc ratio, were related to higher refractive errors in PWA. CONCLUSIONS In PWA, ocular maldevelopment is not just limited to the retina but also involves the ONH. Reduced ppRNFL thickness is consistent with previous reports of reduced ganglion cell numbers in PWA. The thicker rim volumes may be a result of incomplete maturation of the ONH.
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Two novel splicing mutations in the SLC45A2 gene cause Oculocutaneous Albinism Type IV by unmasking cryptic splice sites. J Hum Genet 2015; 60:467-71. [PMID: 26016411 DOI: 10.1038/jhg.2015.56] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/30/2015] [Accepted: 04/26/2015] [Indexed: 11/08/2022]
Abstract
Oculocutaneous albinism (OCA) is characterized by hypopigmentation of the skin, hair and eye, and by ophthalmologic abnormalities caused by a deficiency in melanin biosynthesis. OCA type IV (OCA4) is one of the four commonly recognized forms of albinism, and is determined by mutation in the SLC45A2 gene. Here, we investigated the genetic basis of OCA4 in an Italian child. The mutational screening of the SLC45A2 gene identified two novel potentially pathogenic splicing mutations: a synonymous transition (c.888G>A) involving the last nucleotide of exon 3 and a single-nucleotide insertion (c.1156+2dupT) within the consensus sequence of the donor splice site of intron 5. As computer-assisted analysis for mutant splice-site prediction was not conclusive, we investigated the effects on pre-mRNA splicing of these two variants by using an in vitro minigene approach. Production of mutant transcripts in HeLa cells demonstrated that both mutations cause the almost complete abolishment of the physiologic donor splice site, with the concomitant unmasking of cryptic donor splice sites. To our knowledge, this work represents the first in-depth molecular characterization of splicing defects in a OCA4 patient.
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Schulze Schwering M, Kumar N, Bohrmann D, Msukwa G, Kalua K, Kayange P, Spitzer MS. Refractive errors, visual impairment, and the use of low-vision devices in albinism in Malawi. Graefes Arch Clin Exp Ophthalmol 2015; 253:655-61. [DOI: 10.1007/s00417-015-2943-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 11/29/2022] Open
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35
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Kondo T, Namiki T, Coelho SG, Valencia JC, Hearing VJ. Oculocutaneous albinism: Developing novel antibodies targeting the proteins associated with OCA2 and OCA4. J Dermatol Sci 2015; 77:21-7. [DOI: 10.1016/j.jdermsci.2014.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 10/05/2014] [Accepted: 11/10/2014] [Indexed: 12/31/2022]
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Abstract
The visual system is beautifully crafted to transmit information of the external world to visual processing and cognitive centers in the brain. For visual information to be relayed to the brain, a series of axon pathfinding events must take place to ensure that the axons of retinal ganglion cells, the only neuronal cell type in the retina that sends axons out of the retina, find their way out of the eye to connect with targets in the brain. In the past few decades, the power of molecular and genetic tools, including the generation of genetically manipulated mouse lines, have multiplied our knowledge about the molecular mechanisms involved in the sculpting of the visual system. Here, we review major advances in our understanding of the mechanisms controlling the differentiation of RGCs, guidance of their axons from the retina to the primary visual centers, and the refinement processes essential for the establishment of topographic maps and eye-specific axon segregation. Human disorders, such as albinism and achiasmia, that impair RGC axon growth and guidance and, thus, the establishment of a fully functioning visual system will also be discussed.
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Affiliation(s)
- Lynda Erskine
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Scotland, UK
| | - Eloisa Herrera
- Instituto de Neurosciencias de Alicante, CSIC-UMH, San Juan de Alicante, Spain
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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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Visser M, Kayser M, Grosveld F, Palstra RJ. Genetic variation in regulatory DNA elements: the case of OCA2 transcriptional regulation. Pigment Cell Melanoma Res 2014; 27:169-77. [PMID: 24387780 DOI: 10.1111/pcmr.12210] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 12/20/2013] [Indexed: 12/16/2022]
Abstract
Mutations within the OCA2 gene or the complete absence of the OCA2 protein leads to oculocutaneous albinism type 2. The OCA2 protein plays a central role in melanosome biogenesis, and it is a strong determinant of the eumelanin content in melanocytes. Transcript levels of the OCA2 gene are strongly correlated with pigmentation intensities. Recent studies demonstrated that the transcriptional level of OCA2 is to a large extent determined by the noncoding SNP rs12913832 located 21.5 kb upstream of the OCA2 gene promoter. In this review, we discuss current hypotheses and the available data on the mechanism of OCA2 transcriptional regulation and how this is influenced by genetic variation. Finally, we will explore how future epigenetic studies can be used to advance our insight into the functional biology that connects genetic variation to human pigmentation.
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Affiliation(s)
- Mijke Visser
- Department of Forensic Molecular Biology, Erasmus MC University Medical Center Rotterdam, Rotterdam, The Netherlands
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Hida T, Okura M, Tanaka T, Yamashita T. A case of oculocutaneous albinism type 4: aberrant expression of SLC45A2 transcript with exon skipping. J Dermatol 2014; 41:1019-21. [PMID: 25296693 DOI: 10.1111/1346-8138.12652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tokimasa Hida
- Department of Dermatology, Sapporo Medical University School of Medicine, Sapporo, Japan
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Kosiniak-Kamysz A, Marczakiewicz-Lustig A, Marcińska M, Skowron M, Wojas-Pelc A, Pośpiech E, Branicki W. Increased risk of developing cutaneous malignant melanoma is associated with variation in pigmentation genes and VDR, and may involve epistatic effects. Melanoma Res 2014; 24:388-96. [PMID: 24926819 DOI: 10.1097/cmr.0000000000000095] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cutaneous malignant melanoma (CMM) is a malicious human skin cancer that primarily affects individuals with light pigmentation and heavy sun exposure, but also has a known familial association. Multiple genes and polymorphisms have been reported as low-penetrance susceptibility loci for CMM. Here, we examined 33 candidate polymorphisms located in 11 pigmentation genes and the vitamin D receptor gene (VDR) in a population of 130 cutaneous melanoma patients and 707 healthy controls. The genotypes obtained were evaluated for main association effects and potential gene-gene interactions. MC1R, TYR, VDR and SLC45A2 genes were found to be associated with CMM in our population. The results obtained for major function MC1R mutations were the most significant [with odds ratio (OR)=1.787, confidence interval (CI)=1.320-2.419 and P=1.715(-4)], followed by TYR (rs1393350) (with OR=1.569, CI=1.162-2.118, P=0.003), VDR (GCCC haplotype in rs2238136-rs4516035-rs7139166-rs11568820 block) (with OR=5.653, CI=1.794-17.811, P=0.003) and SLC45A2 (rs16891982) (with OR=0.238, CI=0.057-0.987, P=0.048). The study also detected significant intermolecular epistatic effects between MC1R and TYR, SLC45A2 and VDR, HERC2 and VDR, OCA2 and TPCN2, as well as intramolecular interactions between variants within the genes MC1R and VDR. In the final multivariate logistic regression model for CMM development, only the gene-gene interactions discovered remained significant, showing that epistasis may be an important factor in the risk of melanoma.
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Affiliation(s)
- Agnieszka Kosiniak-Kamysz
- aDepartment of Dermatology, Collegium Medicum of the Jagiellonian University bDepartment of Analytical Biochemistry, Jagiellonian University Medical College cDepartment of Genetics and Evolution, Institute of Zoology, Jagiellonian University dSection of Forensic Genetics, Institute of Forensic Research, Kraków, Poland
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Functional characterization of two novel splicing mutations in the OCA2 gene associated with oculocutaneous albinism type II. Gene 2013; 537:79-84. [PMID: 24361966 DOI: 10.1016/j.gene.2013.11.102] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/10/2013] [Accepted: 11/27/2013] [Indexed: 02/07/2023]
Abstract
Oculocutaneous albinism (OCA) is characterized by hypopigmentation of the skin, hair and eye, and by ophthalmologic abnormalities caused by a deficiency in melanin biosynthesis. OCA type II (OCA2) is one of the four commonly-recognized forms of albinism, and is determined by mutation in the OCA2 gene. In the present study, we investigated the molecular basis of OCA2 in two siblings and one unrelated patient. The mutational screening of the OCA2 gene identified two hitherto-unknown putative splicing mutations. The first one (c.1503+5G>A), identified in an Italian proband and her affected sibling, lies in the consensus sequence of the donor splice site of OCA2 intron 14 (IVS14+5G>A), in compound heterozygosity with a frameshift mutation, c.1450_1451insCTGCCCTGACA, which is predicted to determine the premature termination of the polypeptide chain (p.I484Tfs*19). In-silico prediction of the effect of the IVS14+5G>A mutation on splicing showed a score reduction for the mutant splice site and indicated the possible activation of a newly-created deep-intronic acceptor splice site. The second mutation is a synonymous transition (c.2139G>A, p.K713K) involving the last nucleotide of exon 20. This mutation was found in a young African albino patient in compound heterozygosity with a previously-reported OCA2 missense mutation (p.T404M). In-silico analysis predicted that the mutant c.2139G>A allele would result in the abolition of the splice donor site. The effects on splicing of these two novel mutations were investigated using an in-vitro hybrid-minigene approach that led to the demonstration of the causal role of the two mutations and to the identification of aberrant transcript variants.
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Montoliu L. Snowflake, albinism and conservation. Pigment Cell Melanoma Res 2013; 26:786-7. [PMID: 24152041 DOI: 10.1111/pcmr.12133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Montoliu L, Grønskov K, Wei AH, Martínez-García M, Fernández A, Arveiler B, Morice-Picard F, Riazuddin S, Suzuki T, Ahmed ZM, Rosenberg T, Li W. Increasing the complexity: new genes and new types of albinism. Pigment Cell Melanoma Res 2013; 27:11-8. [PMID: 24066960 DOI: 10.1111/pcmr.12167] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/08/2013] [Accepted: 09/17/2013] [Indexed: 12/24/2022]
Abstract
Albinism is a rare genetic condition globally characterized by a number of specific deficits in the visual system, resulting in poor vision, in association with a variable hypopigmentation phenotype. This lack or reduction in pigment might affect the eyes, skin, and hair (oculocutaneous albinism, OCA), or only the eyes (ocular albinism, OA). In addition, there are several syndromic forms of albinism (e.g. Hermansky-Pudlak and Chediak-Higashi syndromes, HPS and CHS, respectively) in which the described hypopigmented and visual phenotypes coexist with more severe pathological alterations. Recently, a locus has been mapped to the 4q24 human chromosomal region and thus represents an additional genetic cause of OCA, termed OCA5, while the gene is eventually identified. In addition, two new genes have been identified as causing OCA when mutated: SLC24A5 and C10orf11, and hence designated as OCA6 and OCA7, respectively. This consensus review, involving all laboratories that have reported these new genes, aims to update and agree upon the current gene nomenclature and types of albinism, while providing additional insights from the function of these new genes in pigment cells.
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Affiliation(s)
- Lluís Montoliu
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus de Cantoblanco, Madrid, Spain; CIBERER, ISCIII, Madrid, Spain
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Hegyi V, Petrovajová M, Novotný M. An objective assessment of melanin in vitiligo skin treated with Balneo PUVA therapy. Skin Res Technol 2013; 20:108-15. [DOI: 10.1111/srt.12092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2013] [Indexed: 12/01/2022]
Affiliation(s)
- V. Hegyi
- Department of Pediatric Dermatovenerology; Comenius University; Bratislava Slovak Republic
| | - M. Petrovajová
- Department of Pediatric Dermatovenerology; Comenius University; Bratislava Slovak Republic
| | - M. Novotný
- Faculty of Mathematics; Physics and Informatics; Comenius University; Bratislava Slovak Republic
- VIS GRAVIS, s.r.o.; Bratislava Slovak Republic
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