1
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Loftus SK, Gillis MF, Lundh L, Baxter LL, Wedel JC, Watkins-Chow DE, Donovan FX, Sergeev YV, Oetting WS, Pavan WJ, Adams DR. Haplotype-based analysis resolves missing heritability in oculocutaneous albinism type 1B. Am J Hum Genet 2023; 110:1123-1137. [PMID: 37327787 PMCID: PMC10357474 DOI: 10.1016/j.ajhg.2023.05.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 06/18/2023] Open
Abstract
Oculocutaneous albinism (OCA) is a rare disorder of pigment production. Affected individuals have variably decreased global pigmentation and visual-developmental changes that lead to low vision. OCA is notable for significant missing heritability, particularly among individuals with residual pigmentation. Tyrosinase (TYR) is the rate-limiting enzyme in melanin pigment biosynthesis and mutations that decrease enzyme function are one of the most common causes of OCA. We present the analysis of high-depth short-read TYR sequencing data for a cohort of 352 OCA probands, ∼50% of whom were previously sequenced without yielding a definitive diagnostic result. Our analysis identified 66 TYR single-nucleotide variants (SNVs) and small insertion/deletions (indels), 3 structural variants, and a rare haplotype comprised of two common frequency variants (p.Ser192Tyr and p.Arg402Gln) in cis-orientation, present in 149/352 OCA probands. We further describe a detailed analysis of the disease-causing haplotype, p.[Ser192Tyr; Arg402Gln] ("cis-YQ"). Haplotype analysis suggests that the cis-YQ allele arose by recombination and that multiple cis-YQ haplotypes are segregating in OCA-affected individuals and control populations. The cis-YQ allele is the most common disease-causing allele in our cohort, representing 19.1% (57/298) of TYR pathogenic alleles in individuals with type 1 (TYR-associated) OCA. Finally, among the 66 TYR variants, we found several additional alleles defined by a cis-oriented combination of minor, potentially hypomorph-producing alleles at common variant sites plus a second, rare pathogenic variant. Together, these results suggest that identification of phased variants for the full TYR locus are required for an exhaustive assessment for potentially disease-causing alleles.
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Affiliation(s)
- Stacie K Loftus
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA; Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Meredith F Gillis
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Linnea Lundh
- Medical Genetics Branch, National Human Genome Research 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
| | - Dawn E Watkins-Chow
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Frank X Donovan
- Cancer Genomics Unit, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yuri V Sergeev
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - William S Oetting
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - William J Pavan
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - David R Adams
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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2
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Lin S, Sanchez-Bretaño A, Leslie JS, Williams KB, Lee H, Thomas NS, Callaway J, Deline J, Ratnayaka JA, Baralle D, Schmitt MA, Norman CS, Hammond S, Harlalka GV, Ennis S, Cross HE, Wenger O, Crosby AH, Baple EL, Self JE. Evidence that the Ser192Tyr/Arg402Gln in cis Tyrosinase gene haplotype is a disease-causing allele in oculocutaneous albinism type 1B (OCA1B). NPJ Genom Med 2022; 7:2. [PMID: 35027574 PMCID: PMC8758782 DOI: 10.1038/s41525-021-00275-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/19/2021] [Indexed: 01/09/2023] Open
Abstract
Oculocutaneous albinism type 1 (OCA1) is caused by pathogenic variants in the TYR (tyrosinase) gene which encodes the critical and rate-limiting enzyme in melanin synthesis. It is the most common OCA subtype found in Caucasians, accounting for ~50% of cases worldwide. The apparent 'missing heritability' in OCA is well described, with ~25-30% of clinically diagnosed individuals lacking two clearly pathogenic variants. Here we undertook empowered genetic studies in an extensive multigenerational Amish family, alongside a review of previously published literature, a retrospective analysis of in-house datasets, and tyrosinase activity studies. Together this provides irrefutable evidence of the pathogenicity of two common TYR variants, p.(Ser192Tyr) and p.(Arg402Gln) when inherited in cis alongside a pathogenic TYR variant in trans. We also show that homozygosity for the p.(Ser192Tyr)/p.(Arg402Gln) TYR haplotype results in a very mild, but fully penetrant, albinism phenotype. Together these data underscore the importance of including the TYR p.(Ser192Tyr)/p.(Arg402Gln) in cis haplotype as a pathogenic allele causative of OCA, which would likely increase molecular diagnoses in this missing heritability albinism cohort by 25-50%.
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Affiliation(s)
- Siying Lin
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
| | - Aida Sanchez-Bretaño
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Joseph S Leslie
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
| | - Katie B Williams
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - N Simon Thomas
- Faculty of Medicine, University of Southampton, Southampton, UK
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
| | - Jonathan Callaway
- Faculty of Medicine, University of Southampton, Southampton, UK
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
| | - James Deline
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Diana Baralle
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Melanie A Schmitt
- University of Wisconsin School of Medicine and Public Health, Department of Ophthalmology & Visual Sciences, Madison, WI, USA
| | - Chelsea S Norman
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- The Rosalind Franklin Institute, Rutherford Appleton Laboratories, Harwell Science and Innovation Campus, Didcot, UK
| | - Sheri Hammond
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - Gaurav V Harlalka
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
- Rajarshi Shahu College of Pharmacy, Malvihir, Buldana, India
| | - Sarah Ennis
- Department of Human Genetics and Genomic Medicine, University of Southampton, Southampton, UK
| | - Harold E Cross
- Department of Ophthalmology, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Olivia Wenger
- New Leaf Clinic, PO Box 336, 16014 East Chestnut Street, Mount Eaton, OH, 44691, USA
- Department of Pediatrics, Akron Children's Hospital, 214 West Bowery Street, Akron, OH, 44308, USA
| | - Andrew H Crosby
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK.
| | - Emma L Baple
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK.
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Gladstone Road, Exeter, UK.
| | - Jay E Self
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
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3
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Ayala GD, Linderman RE, Valenzuela RK, Woertz EN, Brilliant M, Tarima S, Carroll J. Assessing Foveal Structure in Individuals with TYR R402Q and S192Y Hypomorphic Alleles. OPHTHALMOLOGY SCIENCE 2021; 1:100077. [PMID: 36246950 PMCID: PMC9560529 DOI: 10.1016/j.xops.2021.100077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 10/31/2022]
Abstract
Purpose Design Participants Methods Main Outcome Measures Results Conclusions
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4
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Aamir A, Kuht HJ, Grønskov K, Brooks BP, Thomas MG. Clinical utility gene card for oculocutaneous (OCA) and ocular albinism (OA)-an update. Eur J Hum Genet 2021; 29:1577-1583. [PMID: 33504991 PMCID: PMC8484472 DOI: 10.1038/s41431-021-00809-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/12/2020] [Accepted: 01/08/2021] [Indexed: 02/07/2023] Open
Affiliation(s)
- Abdullah Aamir
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - Helen J Kuht
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - Karen Grønskov
- Rigshospitalet, Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Glostrup, Denmark
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Bethesda, MD, USA
| | - Mervyn G Thomas
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK.
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5
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Dumitrescu AV, Tran J, Pfeifer W, Bhattarai SV, Kemerley A, Dunn TV, Wang K, Scheetz TE, Drack A. Clinical albinism score, presence of nystagmus and optic nerves defects are correlated with visual outcome in patients with oculocutaneous albinism. Ophthalmic Genet 2021; 42:539-552. [PMID: 34251969 DOI: 10.1080/13816810.2021.1933544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Purpose: To correlate clinical features, molecular genetic findings, and visual acuity in a cohort of patients clinically diagnosed with oculocutaneous albinism.Design: Retrospective chart reviewMethods: 58 charts met the inclusion criteria. Clinical examination, ancillary testing, and molecular genetic diagnoses were extracted. A novel clinical albinism score (CAS) was developed.Results: A least one likely pathogenic mutation was found in 44/58 (75.9%) patients. Mutations in the OCA1 gene were the most common (52.3%), followed by OCA2 (34%), OCA4 (2.3%), OA1 (6.8%), and HPS (4.5%). Thirty-four percentage of patients had a complete genotype, 41% had one mutation found and 24% had negative genetic testing. CAS was statistically significantly higher in patients with complete genotype, versus patients with one or no mutations found (p < .01). Better visual acuity was associated with lower CAS and fewer disease-causing mutations (p < .01). Foveal defects and iris transillumination were associated with a higher number of mutations (p < .01). Patients with nystagmus or anomalous optic nerves had worse visual acuity than those who did not (p < .01, p < .05).Conclusions: Patients with a complete genotype were more likely to have higher CAS. Vision loss correlated with complete phenotype and higher CAS, the presence of nystagmus and anomalous optic nerves. Patients with features of albinism in whom an incomplete genotype was found had better vision than those with complete genotype, suggesting a mild occult mutation or modifier variant. Genetic diagnosis is vital for complete diagnosis, counseling, and family planning.
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Affiliation(s)
- Alina V Dumitrescu
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA.,Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Johnny Tran
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Wanda Pfeifer
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Sajag V Bhattarai
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Andrew Kemerley
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Taylor V Dunn
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Kai Wang
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
| | - Tod E Scheetz
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA
| | - Arlene Drack
- Department of Ophthalmology and Visual Science, University of Iowa, Iowa City, IA, USA
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6
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Schidlowski L, Liebert F, Iankilevich PG, Rebellato PRO, Rocha RA, Almeida NAP, Jain A, Wu Y, Itan Y, Rosati R, Prando C. Non-syndromic Oculocutaneous Albinism: Novel Genetic Variants and Clinical Follow Up of a Brazilian Pediatric Cohort. Front Genet 2020; 11:397. [PMID: 32411182 PMCID: PMC7198815 DOI: 10.3389/fgene.2020.00397] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a genetic disorder characterized by skin, hair, and eye hypopigmentation due to a reduction or absence of melanin. Clinical manifestations include vision problems and a high susceptibility to skin cancer. In its non-syndromic form, OCA is associated with six genes and one chromosomal region. Because OCA subtypes are not always clinically distinguishable, molecular analysis has become an important tool for classifying types of OCA, which facilitates genetic counseling and can guide the development of new therapies. We studied eight Brazilian individuals aged 1.5–18 years old with clinical diagnosis of OCA. Assessment of ophthalmologic characteristics showed results consistent with albinism, including reduced visual acuity, nystagmus, and loss of stereoscopic vision. We also observed the appearance of the strabismus and changes in static refraction over a 2-year period. Dermatologic evaluation showed that no participants had preneoplastic skin lesions, despite half of the participants reporting insufficient knowledge about skin care in albinism. Whole-exome and Sanger sequencing revealed eight different mutations: six in the TYR gene and two in the SLC45A2 gene, of which one was novel and two were described in a population study but were not previously associated with the OCA phenotype. We performed two ophthalmological evaluations, 2 years apart; and one dermatological evaluation. To the best of our knowledge, this is the first study to perform clinical follow-up and genetic analysis of a Brazilian cohort with albinism. Here, we report three new OCA causing mutations.
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Affiliation(s)
- Laire Schidlowski
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | - Fernando Liebert
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | | | | | | | | | - Aayushee Jain
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Yiming Wu
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Yuval Itan
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Roberto Rosati
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | - Carolina Prando
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil.,Hospital Pequeno Príncipe, Curitiba, Brazil
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7
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A small gene sequencing panel realises a high diagnostic rate in patients with congenital nystagmus following basic phenotyping. Sci Rep 2019; 9:13229. [PMID: 31519934 PMCID: PMC6744446 DOI: 10.1038/s41598-019-49368-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/26/2019] [Indexed: 11/08/2022] Open
Abstract
Nystagmus is a disorder of uncontrolled eye movement and can occur as an isolated trait (idiopathic INS, IINS) or as part of multisystem disorders such as albinism, significant visual disorders or neurological disease. Eighty-one unrelated patients with nystagmus underwent routine ocular phenotyping using commonly available phenotyping methods and were grouped into four sub-cohorts according to the level of phenotyping information gained and their findings. DNA was extracted and sequenced using a broad utility next generation sequencing (NGS) gene panel. A clinical subpanel of genes for nystagmus/albinism was utilised and likely causal variants were prioritised according to methods currently employed by clinical diagnostic laboratories. We determine the likely underlying genetic cause for 43.2% of participants with similar yields regardless of prior phenotyping. This study demonstrates that a diagnostic workflow combining basic ocular phenotyping and a clinically available targeted NGS panel, can provide a high diagnostic yield for patients with infantile nystagmus, enabling access to disease specific management at a young age and reducing the need for multiple costly, often invasive tests. By describing diagnostic yield for groups of patients with incomplete phenotyping data, it also permits the subsequent design of ‘real-world’ diagnostic workflows and illustrates the changing role of genetic testing in modern diagnostic workflows for heterogeneous ophthalmic disorders.
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8
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Abstract
Human skin and hair color are visible traits that can vary dramatically within and across ethnic populations. The genetic makeup of these traits-including polymorphisms in the enzymes and signaling proteins involved in melanogenesis, and the vital role of ion transport mechanisms operating during the maturation and distribution of the melanosome-has provided new insights into the regulation of pigmentation. A large number of novel loci involved in the process have been recently discovered through four large-scale genome-wide association studies in Europeans, two large genetic studies of skin color in Africans, one study in Latin Americans, and functional testing in animal models. The responsible polymorphisms within these pigmentation genes appear at different population frequencies, can be used as ancestry-informative markers, and provide insight into the evolutionary selective forces that have acted to create this human diversity.
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Affiliation(s)
- William J Pavan
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Richard A Sturm
- Dermatology Research Centre, The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Queensland 4102, Australia;
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9
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Monfermé S, Lasseaux E, Duncombe-Poulet C, Hamel C, Defoort-Dhellemmes S, Drumare I, Zanlonghi X, Dollfus H, Perdomo Y, Bonneau D, Korobelnik JF, Plaisant C, Michaud V, Pennamen P, Rooryck-Thambo C, Morice-Picard F, Paya C, Arveiler B. Mild form of oculocutaneous albinism type 1: phenotypic analysis of compound heterozygous patients with the R402Q variant of the TYR gene. Br J Ophthalmol 2018; 103:1239-1247. [PMID: 30472657 DOI: 10.1136/bjophthalmol-2018-312729] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/23/2018] [Accepted: 11/08/2018] [Indexed: 11/03/2022]
Abstract
AIM Oculocutaneous albinism type 1 (OCA1) is due to TYR mutations. c.1205G>A/p.Arg402Gln (R402Q) is a thermosensitive variant of the TYR gene that has been reported to be responsible for mild forms of OCA1. The aim of our study was to define the phenotype associated with this variant. METHODS In our retrospective series, among 268 patients diagnosed with OCA1, 122 (45.5%) harboured one pathogenic variant of TYR, and the R402Q variant ensured to be in trans by segregation analysis in 69 patients (25.7%), constituting the 'R402Q-OCA1' group. 146 patients harboured two pathogenic variants of the TYR gene other than R402Q. Clinical records were available for 119 of them, constituting the 'Classical-OCA1' group. RESULTS Most R402Q-OCA1 patients presented with white or yellow-white hair at birth (71.43%), blond hair later (46.97%), a light phototype but with residual pigmentation (69.64%), and blue eyes (76.56%). Their pigmentation was significantly higher than in the classical-OCA1 group. All patients from the R402Q-OCA1 group presented with ocular features of albinism. However the prevalence of photophobia (78.13%) and iris transillumination (83.87%) and the severity scores of iris transillumination, retinal hypopigmentation and foveal hypoplasia were lower in the R402Q-OCA1 group. Visual acuity was higher in the R402Q-OCA1 group (0.38±0.21 logarithm of the minimum angle of resolution vs 0.76±0.24). Investigations concerning a possible additive effect of the c.575C>A/p.Ser192 (S192Y) variant of TYR in cis with R402Q, suggested by others, showed no significant impact on the phenotype. CONCLUSION The R402Q variant leads to variable but generally mild forms of albinism whose less typical presentation may lead to underdiagnosis.
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Affiliation(s)
| | - Eulalie Lasseaux
- Service de génétique médicale, CHU de Bordeaux, Bordeaux, France
| | | | - Christian Hamel
- Service d'ophtalmologie, Equipe maladies sensorielles génétiques, CHU de Montpellier, Montpellier, France
| | | | - Isabelle Drumare
- Service d'exploration de la vision et neuro-ophtalmologie, CHRU de Lille, Lille, France
| | | | - Hélène Dollfus
- Centre des affections rares en génétique ophtalmologique, CHU de Strasbourg, Strasbourg, France
| | - Yaurama Perdomo
- Centre des affections rares en génétique ophtalmologique, CHU de Strasbourg, Strasbourg, France
| | | | | | - Claudio Plaisant
- Service de génétique médicale, CHU de Bordeaux, Bordeaux, France
| | - Vincent Michaud
- Service de génétique médicale, CHU de Bordeaux, Bordeaux, France
| | - Perrine Pennamen
- Service de génétique médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | - Caroline Rooryck-Thambo
- Service de génétique médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | - Fanny Morice-Picard
- Service de dermatologie, Unité de dermato-pédiatrie du CHU de Bordeaux, Bordeaux, France
| | - Clement Paya
- Centre d'ophtalmologie du Palais Gallien, Bordeaux, France
| | - Benoit Arveiler
- Service de génétique médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
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10
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Wang NK, Chiang JPW. Increasing evidence of combinatory variant effects calls for revised classification of low-penetrance alleles. Genet Med 2018; 21:1280-1282. [PMID: 30385887 PMCID: PMC6752265 DOI: 10.1038/s41436-018-0347-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/15/2018] [Indexed: 11/09/2022] Open
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11
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Rauschendorf MA, Zimmer AD, Laut A, Demmer P, Rösler B, Happle R, Sartori S, Fischer J. Homozygous intronic MITF mutation causes severe Waardenburg syndrome type 2A. Pigment Cell Melanoma Res 2018; 32:85-91. [PMID: 30117279 DOI: 10.1111/pcmr.12733] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marc-Alexander Rauschendorf
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Andreas D Zimmer
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Astrid Laut
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Philipp Demmer
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Bernd Rösler
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Rudolf Happle
- Department of Dermatology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Judith Fischer
- Institute of Human Genetics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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12
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Lasseaux E, Plaisant C, Michaud V, Pennamen P, Trimouille A, Gaston L, Monfermé S, Lacombe D, Rooryck C, Morice-Picard F, Arveiler B. Molecular characterization of a series of 990 index patients with albinism. Pigment Cell Melanoma Res 2018; 31:466-474. [PMID: 29345414 DOI: 10.1111/pcmr.12688] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/07/2018] [Indexed: 01/11/2023]
Abstract
Albinism is a clinically and genetically heterogeneous disease characterized by variable degrees of hypopigmentation and by nystagmus, foveal hypoplasia, and chiasmatic misrouting of the optic nerves. The wide phenotypic heterogeneity impedes the establishment of phenotype-genotype correlations. To obtain a precise diagnosis, we screened the 19 known albinism genes in 990 index patients using targeted next-generation sequencing (NGS) and high-resolution comparative genomic hybridization. A molecular diagnosis was obtained in 72.32% of patients. A total of 243 new pathogenic variants were identified. Intragenic rearrangements represented 10.8% of all pathogenic alleles. NGS panel analysis allowed establishing a diagnosis for the rarest forms of the disease, which could not be diagnosed otherwise. Because of the clinical overlap between the different forms of the disease, diagnosis nowadays clearly relies on molecular grounds.
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Affiliation(s)
- Eulalie Lasseaux
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
| | - Claudio Plaisant
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
| | - Vincent Michaud
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
| | - Perrine Pennamen
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | - Aurelien Trimouille
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | - Laetitia Gaston
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
| | | | - Didier Lacombe
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | - Caroline Rooryck
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | | | - Benoît Arveiler
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
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13
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Goldstein AM, Xiao Y, Sampson J, Zhu B, Rotunno M, Bennett H, Wen Y, Jones K, Vogt A, Burdette L, Luo W, Zhu B, Yeager M, Hicks B, Han J, De Vivo I, Koutros S, Andreotti G, Beane-Freeman L, Purdue M, Freedman ND, Chanock SJ, Tucker MA, Yang XR. Rare germline variants in known melanoma susceptibility genes in familial melanoma. Hum Mol Genet 2017; 26:4886-4895. [PMID: 29036293 PMCID: PMC5886297 DOI: 10.1093/hmg/ddx368] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/11/2017] [Accepted: 09/19/2017] [Indexed: 12/20/2022] Open
Abstract
Known high-risk cutaneous malignant melanoma (CMM) genes account for melanoma risk in <40% of melanoma-prone families, suggesting the existence of additional high-risk genes or perhaps a polygenic mechanism involving multiple genetic modifiers. The goal of this study was to systematically characterize rare germline variants in 42 established melanoma genes among 144 CMM patients in 76 American CMM families without known mutations using data from whole-exome sequencing. We identified 68 rare (<0.1% in public and in-house control datasets) nonsynonymous variants in 25 genes. We technically validated all loss-of-function, inframe insertion/deletion, and missense variants predicted as deleterious, and followed them up in 1, 559 population-based CMM cases and 1, 633 controls. Several of these variants showed disease co-segregation within families. Of particular interest, a stopgain variant in TYR was present in five of six CMM cases/obligate gene carriers in one family and a single population-based CMM case. A start gain variant in the 5'UTR region of PLA2G6 and a missense variant in ATM were each seen in all three affected people in a single family, respectively. Results from rare variant burden tests showed that familial and population-based CMM patients tended to have higher frequencies of rare germline variants in albinism genes such as TYR, TYRP1, and OCA2 (P < 0.05). Our results suggest that rare nonsynonymous variants in low- or intermediate-risk CMM genes may influence familial CMM predisposition, warranting further investigation of both common and rare variants in genes affecting functionally important pathways (such as melanogenesis) in melanoma risk assessment.
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Affiliation(s)
- Alisa M Goldstein
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Yanzi Xiao
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Joshua Sampson
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Bin Zhu
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Melissa Rotunno
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Hunter Bennett
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Yixuan Wen
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Kristine Jones
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Aurelie Vogt
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Laurie Burdette
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Wen Luo
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Bin Zhu
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Meredith Yeager
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Belynda Hicks
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
- Cancer Genomics Research Laboratory, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Jiali Han
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Epidemiology, Richard M. Fairbanks School of Public Health, Melvin & Bren Simon Cancer Center, Indiana University, Indianapolis, IN, USA
| | - Immaculata De Vivo
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Stella Koutros
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Gabriella Andreotti
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Laura Beane-Freeman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Mark Purdue
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Neal D Freedman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Stephen J Chanock
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Margaret A Tucker
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
| | - Xiaohong R Yang
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD, USA
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14
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Dolinska MB, Kus NJ, Farney SK, Wingfield PT, Brooks BP, Sergeev YV. Oculocutaneous albinism type 1: link between mutations, tyrosinase conformational stability, and enzymatic activity. Pigment Cell Melanoma Res 2017; 30:41-52. [PMID: 27775880 DOI: 10.1111/pcmr.12546] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022]
Abstract
Oculocutaneous albinism type 1 (OCA1) is an autosomal recessive disorder caused by mutations in the tyrosinase gene. Two subtypes of OCA1 have been described: severe OCA1A with complete absence of tyrosinase activity and less severe OCA1B with residual tyrosinase activity. Here, we characterize the recombinant human tyrosinase intramelanosomal domain and mutant variants, which mimic genetic changes in both subtypes of OCA1 patients. Proteins were prepared using site-directed mutagenesis, expressed in insect larvae, purified by chromatography, and characterized by enzymatic activities, tryptophan fluorescence, and Gibbs free energy changes. The OCA1A mutants showed very low protein expression and protein yield and are enzymatically inactive. Mutants mimicking OCA1B were biochemically similar to the wild type, but exhibited lower specific activities and protein stabilities. The results are consistent with clinical data, which indicates that OCA1A mutations inactivate tyrosinase and result in severe phenotype, while OCA1B mutations partially inactivate tyrosinase and result in OCA1B albinism.
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Affiliation(s)
- Monika B Dolinska
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Nicole J Kus
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - S Katie Farney
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Paul T Wingfield
- National Institute of Artritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Brian P Brooks
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yuri V Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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15
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Marti A, Lasseaux E, Ezzedine K, Léauté-Labrèze C, Boralevi F, Paya C, Coste V, Deroissart V, Arveiler B, Taieb A, Morice-Picard F. Lessons of a day hospital: Comprehensive assessment of patients with albinism in a European setting. Pigment Cell Melanoma Res 2017; 31:318-329. [DOI: 10.1111/pcmr.12651] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 09/22/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Aurélie Marti
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
| | | | - Khaled Ezzedine
- Department of Dermatology; AP-HP; Hôpital Henri-Mondor; Créteil France
| | - Christine Léauté-Labrèze
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
| | - Franck Boralevi
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
| | - Clément Paya
- Ophthalmology Department; CHU de Bordeaux; Bordeaux France
| | | | - Vincent Deroissart
- Institute of Public Health; Epidemiology and Development “ISPED”; Bordeaux University; Bordeaux France
| | - Benoit Arveiler
- Molecular Genetics Laboratory; CHU de Bordeaux; Bordeaux France
- Unité INSERM U1211; Maladies Rares: Génétique et Métabolisme; Bordeaux France
| | - Alain Taieb
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
- Unité INSERM 1035; BMGIC; Immuno-dermatology ATIP-AVENIR; University of Bordeaux; Bordeaux France
| | - Fanny Morice-Picard
- Paediatric Dermatology Unit; National Reference Center for Rare Skin Disorders; Hôpital Pellegrin-Enfants; Bordeaux University Hospitals; Bordeaux France
- Molecular Genetics Laboratory; CHU de Bordeaux; Bordeaux France
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16
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Identification of a functionally significant tri-allelic genotype in the Tyrosinase gene (TYR) causing hypomorphic oculocutaneous albinism (OCA1B). Sci Rep 2017; 7:4415. [PMID: 28667292 PMCID: PMC5493628 DOI: 10.1038/s41598-017-04401-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/05/2017] [Indexed: 12/04/2022] Open
Abstract
Oculocutaneous albinism (OCA) and ocular albinism (OA) are inherited disorders of melanin biosynthesis, resulting in loss of pigment and severe visual deficits. OCA encompasses a range of subtypes with overlapping, often hypomorphic phenotypes. OCA1 is the most common cause of albinism in European populations and is inherited through autosomal recessive mutations in the Tyrosinase (TYR) gene. However, there is a high level of reported missing heritability, where only a single heterozygous mutation is found in TYR. This is also the case for other OCA subtypes including OCA2 caused by mutations in the OCA2 gene. Here we have interrogated the genetic cause of albinism in a well phenotyped, hypomorphic albinism population by sequencing a broad gene panel and performing segregation studies on phenotyped family members. Of eighteen probands we can confidently diagnose three with OA and OCA2, and one with a PAX6 mutation. Of six probands with only a single heterozygous mutation in TYR, all were found to have the two common variants S192Y and R402Q. Our results suggest that a combination of R402Q and S192Y with a deleterious mutation in a ‘tri-allelic genotype’ can account for missing heritability in some hypomorphic OCA1 albinism phenotypes.
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17
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Thomas MG, Maconachie GDE, Sheth V, McLean RJ, Gottlob I. Development and clinical utility of a novel diagnostic nystagmus gene panel using targeted next-generation sequencing. Eur J Hum Genet 2017; 25:725-734. [PMID: 28378818 PMCID: PMC5477371 DOI: 10.1038/ejhg.2017.44] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 02/20/2017] [Accepted: 03/01/2017] [Indexed: 11/09/2022] Open
Abstract
Infantile nystagmus (IN) is a genetically heterogeneous disorder arising from variants of genes expressed within the developing retina and brain. IN presents a diagnostic challenge and patients often undergo numerous investigations. We aimed to develop and assess the utility of a next-generation sequencing (NGS) panel to enhance the diagnosis of IN. We identified 336 genes associated with IN from the literature and OMIM. NimbleGen Human custom array was used to enrich the target genes and sequencing was performed using HiSeq2000. Using reference genome material (NA12878), we show the sensitivity (98.5%) and specificity (99.9%) of the panel. Fifteen patients with familial IN were sequenced using the panel. Two authors were masked to the clinical diagnosis. We identified variants in 12/15 patients in the following genes: FRMD7 (n=3), CACNA1F (n=2), TYR (n=5), CRYBA1 (n=1) and TYRP1 (n=1). In 9/12 patients, the clinical diagnosis was consistent with the genetic diagnosis. In 3/12 patients, the results from the genetic diagnoses (TYR, CRYBA1 and TYRP1 variants) enabled revision of clinical diagnoses. In 3/15 patients, we were unable to determine a genetic diagnosis. In one patient, copy number variation analysis revealed a FRMD7 deletion. This is the first study establishing the clinical utility of a diagnostic NGS panel for IN. We show that the panel has high sensitivity and specificity. The genetic information from the panel will lead to personalised diagnosis and management of IN and enable accurate genetic counselling. This will allow development of a new clinical care pathway for IN.
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Affiliation(s)
- Mervyn G Thomas
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Gail DE Maconachie
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Viral Sheth
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Rebecca J McLean
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Irene Gottlob
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
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18
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Clinical evaluation and molecular screening of a large consecutive series of albino patients. J Hum Genet 2016; 62:277-290. [PMID: 27734839 DOI: 10.1038/jhg.2016.123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 09/08/2016] [Accepted: 09/10/2016] [Indexed: 12/26/2022]
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. In this study we recruited 321 albino patients and screened them for the genes known to cause oculocutaneous albinism (OCA1-4 and OCA6) and ocular albinism (OA1). Our purpose was to detect mutations and genetic frequencies of the main causative genes, offering to albino patients an exhaustive diagnostic assessment within a multidisciplinary approach including ophthalmological, dermatological, audiological and genetic evaluations. We report 70 novel mutations and the frequencies of the major causative OCA genes that are as follows: TYR (44%), OCA2 (17%), TYRP1 (1%), SLC45A2 (7%) and SLC24A5 (<0.5%). An additional 5% of patients had GPR143 mutations. In 19% of cases, a second reliable mutation was not detected, whereas 7% of our patients remain still molecularly undiagnosed. This comprehensive study of a consecutive series of OCA/OA1 patients allowed us to perform a clinical evaluation of the different OCA forms.
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19
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Urtatiz O, Sanabria D, Lattig MC. Oculocutaneous albinism (OCA) in Colombia: First molecular screening of the TYR and OCA2 genes in South America. J Dermatol Sci 2014; 76:260-2. [DOI: 10.1016/j.jdermsci.2014.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 09/03/2014] [Accepted: 09/25/2014] [Indexed: 11/29/2022]
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20
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Ghodsinejad Kalahroudi V, Kamalidehghan B, Arasteh Kani A, Aryani O, Tondar M, Ahmadipour F, Chung LY, Houshmand M. Two novel tyrosinase (TYR) gene mutations with pathogenic impact on oculocutaneous albinism type 1 (OCA1). PLoS One 2014; 9:e106656. [PMID: 25216246 PMCID: PMC4162572 DOI: 10.1371/journal.pone.0106656] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 08/06/2014] [Indexed: 11/19/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a heterogeneous group of autosomal recessive disorders resulting from mutations of the tyrosinase (TYR) gene and presents with either complete or partial absence of pigment in the skin, hair and eyes due to a defect in an enzyme involved in the production of melanin. In this study, mutations in the TYR gene of 30 unrelated Iranian OCA1 patients and 100 healthy individuals were examined using PCR-sequencing. Additionally, in order to predict the possible effects of new mutations on the structure and function of tyrosinase, these mutations were analyzed by SIFT, PolyPhen and I-Mutant 2 software. Here, two new pathogenic p.C89S and p.H180R mutations were detected in two OCA1 patients. Moreover, the R402Q and S192Y variants, which are common non-pathogenic polymorphisms, were detected in 17.5% and 35% of the patients, respectively. The outcome of this study has extended the genotypic spectrum of OCA1 patients, which paves the way for more efficient carrier detection and genetic counseling.
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Affiliation(s)
- Vadieh Ghodsinejad Kalahroudi
- Department of Biology, Kharazmi University, Tehran, Iran
- Department of Medical Genetics, Special Medical Center, Tehran, Iran
| | - Behnam Kamalidehghan
- Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | | | - Omid Aryani
- Department of Medical Genetics, Special Medical Center, Tehran, Iran
| | - Mahdi Tondar
- Department of Medical Genetics, Special Medical Center, Tehran, Iran
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, D.C., United States of America
| | - Fatemeh Ahmadipour
- Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Lip Yong Chung
- Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Massoud Houshmand
- Department of Medical Genetics, Special Medical Center, Tehran, Iran
- Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
- * E-mail:
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21
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Jagirdar K, Smit DJ, Ainger SA, Lee KJ, Brown DL, Chapman B, Zhen Zhao Z, Montgomery GW, Martin NG, Stow JL, Duffy DL, Sturm RA. Molecular analysis of common polymorphisms within the human Tyrosinase locus and genetic association with pigmentation traits. Pigment Cell Melanoma Res 2014; 27:552-64. [PMID: 24739399 DOI: 10.1111/pcmr.12253] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 04/14/2014] [Indexed: 01/13/2023]
Abstract
We have compared the melanogenic activities of cultured melanocytes carrying two common TYR alleles as homozygous 192S-402R wild-type, heterozygous and homozygous variant. This includes assays of TYR protein, DOPAoxidase activity, glycosylation and temperature sensitivity of protein and DOPAoxidase levels. Homozygous wild-type strains on average had higher levels of TYR protein and enzyme activity than other genotypes. Homozygous 402Q/Q melanocytes produced significantly less TYR protein, displayed altered trafficking and glycosylation, with reduced DOPAoxidase. However, near wild-type TYR activity levels could be recovered at lower growth temperature. In a sample population from Southeast Queensland, these two polymorphisms were present on four TYR haplotypes, designated as WT 192S-402R, 192Y-402R and 192S-402Q with a double-variant 192Y-402Q of low frequency at 1.9%. Based on cell culture findings and haplotype associations, we have used an additive model to assess the penetrance of the ten possible TYR genotypes derived from the combination of these haplotypes.
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Affiliation(s)
- Kasturee Jagirdar
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld, Australia
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22
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Rooryck C, Morice F, Lacombe D, Taieb A, Arveiler B. Genetic basis of oculocutaneous albinism. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.09.53] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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Sutherland JE, Day MA. Advantages and disadvantages of molecular testing in ophthalmology. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.11.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Simeonov DR, Wang X, Wang C, Sergeev Y, Dolinska M, Bower M, Fischer R, Winer D, Dubrovsky G, Balog JZ, Huizing M, Hart R, Zein WM, Gahl WA, Brooks BP, Adams DR. DNA variations in oculocutaneous albinism: an updated mutation list and current outstanding issues in molecular diagnostics. Hum Mutat 2013; 34:827-35. [PMID: 23504663 DOI: 10.1002/humu.22315] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/08/2013] [Indexed: 12/20/2022]
Abstract
Oculocutaneous albinism (OCA) is a rare genetic disorder of melanin synthesis that results in hypopigmented hair, skin, and eyes. There are four types of OCA caused by mutations in TYR (OCA-1), OCA2 (OCA-2), TYRP1 (OCA-3), or SLC45A2 (OCA-4). Here we report 22 novel mutations in the OCA genes; 14 from a cohort of 61 patients seen as part of the NIH OCA Natural History Study and eight from a prior study at the University of Minnesota. We also include a comprehensive list of almost 600 previously reported OCA mutations along with ethnicity information, carrier frequencies, and in silico pathogenicity predictions as a supplement. In addition to discussing the clinical and molecular features of OCA, we address the cases of apparent missing heritability. In our cohort, 26% of patients did not have two mutations in a single OCA gene. We demonstrate the utility of multiple detection methods to reveal mutations missed by Sanger sequencing. Finally, we review the TYR p.R402Q temperature-sensitive variant and confirm its association with cases of albinism with only one identifiable TYR mutation.
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Affiliation(s)
- Dimitre R Simeonov
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
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25
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Abstract
Genome-wide association studies and comparative genomics have established major loci and specific polymorphisms affecting human skin, hair and eye color. Environmental changes have had an impact on selected pigmentation genes as populations have expanded into different regions of the globe.
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Affiliation(s)
- Richard A Sturm
- Institute for Molecular Bioscience, Melanogenix Group, The University of Queensland, Brisbane, Qld 4072, Australia.
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26
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Brooks BP. Making progress in albinism. J AAPOS 2011; 15:1-2. [PMID: 21397796 DOI: 10.1016/j.jaapos.2011.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 01/14/2011] [Indexed: 11/25/2022]
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27
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Chiang PW, Spector E, McGregor TL. Evidence suggesting digenic inheritance of Waardenburg syndrome type II with ocular albinism. Am J Med Genet A 2009; 149A:2739-44. [DOI: 10.1002/ajmg.a.33128] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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