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Dutta T, Ganguly K, Saha A, Sil A, Ray K, Sengupta M. Identifying genetic defects in oculocutaneous albinism patients of West Bengal, Eastern India. Mol Biol Rep 2024; 51:818. [PMID: 39014059 DOI: 10.1007/s11033-024-09777-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 07/03/2024] [Indexed: 07/18/2024]
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a congenital heterogeneous group of autosomal recessive disorders characterized by the absence or loss of melanin in the skin, eyes and hair of the affected individuals. Based on the mutated gene, OCA has been classified into eight sub-types (OCA1-8) with overlapping clinical phenotypes. Mutations in the TYR gene cause OCA1, the most prevalent OCA worldwide including India. Mutations in OCA2 and SLC45A2, both of which regulate melanosomal pH that is critical to TYR activity, cause OCA2 and OCA4 respectively, the other common OCA subtypes in India. METHODS In the present study, we have included 54 OCA-affected cases from 41 unrelated families representing 16 different marriage/ethnic groups from 17 districts of West Bengal, India. We pursued a PCR-sequencing based approach followed by bioinformatic analysis to identify mutations in TYR, OCA2 and SLC45A2 genes. RESULTS Mutations were detected in 27 of the 54 (50%) OCA patients from 18 unrelated families, representing 9 different marriage/ethnic groups from 11 districts of West Bengal. Three TYR variants: NM_000372.4: c.391 A > G, NP_000363.1: p. Lys131Glu; NM_000372.4: c.1037G > T; NP_000363.1: p. Gly346Val, NM_000372.4: c.715 C > T; NP_000363.1:p.Arg239Trp was identified for the first time in Eastern Indian OCA cases. A novel nonsense variant: NM_016180.5: c.389 T > A, NP_057264.4: p. Leu130* and a novel synonymous variation NM_016180.5: c.1092 A > G; NP_057264.4: p.364E = were identified in SLC45A2. Additionally, NM_016180.5: c.904A > T; NP_057264.4: p. Thre302Ser was identified for the first time in any Eastern Indian OCA case. We identified 2 previously reported mutations in OCA2. In concordance with previous reports, NM_000372.4: c.832C > T, NP_000363.1: p. (Arg278*) was the commonest TYR mutation. CONCLUSION The results of our study enrich the mutational spectrum of the known OCA causing genes in Eastern India, which would facilitate accurate diagnosis, familial screening, carrier detection and containment of the disease load.
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Affiliation(s)
- Tithi Dutta
- Department of Genetics, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Kausik Ganguly
- Department of Genetics, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Arpan Saha
- Department of Genetics, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Asim Sil
- Vivekananda Mission Ashram Netra Niramay Niketan, Purba Midnapore, Haldia, West Bengal, India
| | - Kunal Ray
- ATGC Diagnostics Pvt. Ltd., 21/2A Gorachand Road, Park Circus, Kolkata, West Bengal, India
| | - Mainak Sengupta
- Department of Genetics, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India.
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Chen C, Li J, Wang B, Wang Y, Yu X. TYR mutation in a Chinese population with oculocutaneous albinism: Molecular characteristics and ophthalmic manifestations. Exp Eye Res 2024; 239:109761. [PMID: 38145795 DOI: 10.1016/j.exer.2023.109761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/07/2023] [Accepted: 12/19/2023] [Indexed: 12/27/2023]
Abstract
Oculocutaneous albinism (OCA) is a rare inherited disorder characterized by a partial or complete reduction of melanin biosynthesis that leads to hypopigmentation in the skin, hair and eyes. The OCA1 subtype is caused by mutations in TYR. The purpose of this study was to investigate the genetic and clinical ophthalmic characteristics of TYR mutations in patients with OCA. Herein, 51 probands with a clinical diagnosis of OCA were enrolled. Whole-exome sequencing and comprehensive ophthalmic examinations were performed. Overall, TYR mutations were detected in 37.3% (19/51) in the patients with OCA. Fifteen patients had compound heterozygous variants, and four cases had homozygous variants. Eleven different pathogenic variants in TYR were detected in these 19 patients, with missense, insertion, delins and nonsense in 71.1% (27/38), 15.8% (6/38), 2.6% (1/38), and 10.5% (4/38), respectively. Clinical examinations revealed that 84.2% (16/19) of patients were OCA1A, and 15.8% (3/19) were OCA1B. Most TYR probands (52.6%, 10/19) had moderate vision impairment, 15.8% (3/19) had severe visual impairment, 10.5% (2/19) exhibited blindness, only 5.3% (1/19) had mild visual impairment and 15.8% (3/19) were not available. Photophobia and nystagmus were found in 100% (19/19) of the patients. In addition, grade 4 foveal hypoplasia was detected in 100% (12/12) of the patients. In conclusion: The TYR patients exhibited severe ocular phenotypes: the majority (93.8%, 15/16) of them had a moderate vision impairment or worse, and 100% (12/12) had severe grade 4 foveal hypoplasia. These novel findings could provide insight into the understanding of OCA.
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Affiliation(s)
- Chonglin Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Jun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Bingqi Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Yinghuan Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Xinping Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China.
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Kohli S, Saxena R, Puri RD, Bijarnia Mahay S, Pal S, Dubey S, Arora V, Verma I. The molecular landscape of oculocutaneous albinism in India and its therapeutic implications. Eur J Hum Genet 2023:10.1038/s41431-023-01496-5. [PMID: 38030918 DOI: 10.1038/s41431-023-01496-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 10/14/2023] [Accepted: 11/08/2023] [Indexed: 12/01/2023] Open
Abstract
Oculocutaneous albinism is an inherited disorder of melanin biosynthesis, characterized by absent or reduced pigmentation of the skin, hair, and eyes. Molecular alterations of genes that cause non-syndromic albinism in Asian Indians are poorly characterized. This information would be useful for developing therapies for this disorder. We analyzed 164 persons with non-syndromic albinism, belonging to unrelated families from all parts of India, for molecular changes in the causative genes. Subjects with white hair, white skin, and red iris had their tyrosinase gene sequenced and were also tested by MLPA for deletions/duplications. Subjects with negative results or with darker skin, golden/brown or darker hair had sequencing of TYR, P, TYRP1, SLC45A2 and GPR143 genes. Pathogenic variants in TYR (OCA1) were observed in 139 (84.7%) patients, in the P gene (OCA2) in 20 (12.2%), in TYRP1 (OCA3) in two (1.2%), in SLC45A2 (OCA 4) in one (0.61%), and in GPR143 (X-linked ocular albinism) in two (1.2%) patients. Of 278 alleles with variants in TYR, 179 (64.3%) alleles had (p.R278*) alteration, suggesting the possibility of therapy with a stop codon readthrough molecule. We report 20 patients with 13 disease associated variants in the P gene and 18 novel pathogenic variants in TYR, P, TYRP1, SLC45A2 and GPR143 genes. The data are compared with those reported from India, Pakistan and rest of the world. The therapeutic options in albinism are briefly described, opening this field for future therapies.
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Affiliation(s)
- Sudha Kohli
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India.
| | - Renu Saxena
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Ratna Dua Puri
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Sunita Bijarnia Mahay
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Swasti Pal
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Sudhisha Dubey
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Veronica Arora
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India
| | - Ishwar Verma
- Institute of Medical Genetics and Genomics, Ganga Ram Institute of Postgraduate Medical Education and Research, Sir Ganga Ram Hospital, New Delhi, 110060, India.
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Stroupe S, Martone C, McCann B, Juras R, Kjöllerström HJ, Raudsepp T, Beard D, Davis BW, Derr JN. Chromosome-level reference genome for North American bison (Bison bison) and variant database aids in identifying albino mutation. G3 (BETHESDA, MD.) 2023; 13:jkad156. [PMID: 37481261 PMCID: PMC10542314 DOI: 10.1093/g3journal/jkad156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/24/2023]
Abstract
We developed a highly contiguous chromosome-level reference genome for North American bison to provide a platform to evaluate the conservation, ecological, evolutionary, and population genomics of this species. Generated from a F1 hybrid between a North American bison dam and a domestic cattle bull, completeness and contiguity exceed that of other published bison genome assemblies. To demonstrate the utility for genome-wide variant frequency estimation, we compiled a genomic variant database consisting of 3 true albino bison and 44 wild-type pelage color bison. Through the examination of genomic variants fixed in the albino cohort and absent in the controls, we identified a nonsynonymous single nucleotide polymorphism (SNP) mutation on chromosome 29 in exon 3 of the tyrosinase gene (c.1114C>T). A TaqMan SNP Genotyping Assay was developed to genotype this SNP in a total of 283 animals across 29 herds. This assay confirmed the absence of homozygous variants in all animals except 7 true albino bison included in this study. In addition, the only heterozygous animals identified were 2 wild-type pelage color dams of albino offspring. Therefore, we propose that this new high-quality bison genome assembly and incipient variant database provides a highly robust and informative resource for genomics investigations for this iconic North American species.
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Affiliation(s)
- Sam Stroupe
- Department of Veterinary Pathobiology, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Carly Martone
- Department of Veterinary Pathobiology, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Blake McCann
- National Park Service, Theodore Roosevelt National Park, Medora, ND 58645, USA
| | - Rytis Juras
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Helena Josefina Kjöllerström
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Terje Raudsepp
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - Donald Beard
- Texas Parks and Wildlife, Caprock Canyons State Park & Trailway, Quitaque, TX 79255, USA
| | - Brian W Davis
- Department of Veterinary Integrative Biosciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
- Department of Small Animal Clinical Sciences, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
| | - James N Derr
- Department of Veterinary Pathobiology, Texas A&M University School of Veterinary Medicine and Biomedical Science, College Station, TX 77843, USA
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5
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Ullah MI. Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review. Genes (Basel) 2022; 13:genes13061072. [PMID: 35741834 PMCID: PMC9222488 DOI: 10.3390/genes13061072] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 02/01/2023] Open
Abstract
Oculocutaneous albinism (OCA) is an autosomal recessive syndromic and non-syndromic defect with deficient or a complete lack of the melanin pigment. The characteristics of OCA appears in skin, hair, and eyes with variable degree of pigmentation. Clinical manifestations of OCA include nystagmus, photophobia, reduced visual acuity, hypo-plastic macula, and iris trans-illumination. There are eight OCA types (OCA1–8) documented with non-syndromic characteristics. Molecular studies identified seven genes linked to the OCA phenotype (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, C10orf11, and DCT) and one locus (OCA5) in consanguineous and sporadic albinism. The complications of OCA result in skin cancer and variable syndromes such as Hermansky–Pudlak syndrome (HPS) Chediak–Higashi syndrome (CHS). In the Pakistani population, autosomal recessive non-syndromic OCA is common and is associated with a large number of consanguineous families, and mutations in genes of non-syndromic types are reported. This review highlights the updates on the genetic mutation of OCA genes reported from Pakistani families. Several studies reported the genetic mutations in OCA1, OCA2, OCA3, OCA4, and OCA6 albinism in Pakistani families. A locus, OCA5, was also reported from the Pakistani population, but the gene has not been identified. A new type of OCA8 was identified due to the DCT gene mutation, and it is also reviewed here.
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Affiliation(s)
- Muhammad Ikram Ullah
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 75471, Aljouf, Saudi Arabia
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6
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Ganguly K, Dutta T, Saha A, Sarkar D, Sil A, Ray K, Sengupta M. Mapping the TYR gene reveals novel and previously reported variants in Eastern Indian patients highlighting preponderance of the same changes in multiple unrelated ethnicities. Ann Hum Genet 2020; 84:303-312. [PMID: 32115698 DOI: 10.1111/ahg.12376] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 11/30/2022]
Abstract
Oculocutaneous albinism (OCA) is a group of congenital autosomal recessive disorders with seven known subtypes (OCA1-OCA7) characterized by loss or absence of pigmentation in the skin, hair, and eyes. OCA1, caused by pathogenic variations in the tyrosinase (TYR) gene, has been documented to be the most prevalent subtype across the world including India. In the present study, we recruited 53 OCA-affected individuals from 45 unrelated families belonging to 20 different marriage groups/ethnicities of 15 different districts of West Bengal. We took a targeted sequencing-based approach to find the causal variations in the TYR gene. We report here identification of two novel potentially pathogenic variations [NM_000372.4:c.614C>T, NP_000363.1:p.(Pro205Leu), and NM_000372.4:c.1036+1=/G>T], one novel synonymous TYR variant [NM_000372.4:c.204=/A>G, NP_000363.1:p.(Gln68=)], two pathogenic variations documented for the first time in Indian OCA cases [NM_000372.4:c.1147G>A, NP_000363.1:p.(Asp383Asn), and NM_000372.4:c.585G>A, NP_000363.1:p.(Trp195*)], along with nine previously reported pathogenic variants in 36 out of 53 (∼68%) patients recruited. We report common haplotype backgrounds for the two most prevalent variations [NM_000372.4:c.124G>A, NM_000372.4:c.832C>T] in cases belonging to different marriage/ethnic groups, suggesting a possible founder effect. To our knowledge, this is the most comprehensive genetic study on OCA1 from India, firmly establishing OCA1 as the commonest form of albinism in this part of the world.
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Affiliation(s)
- Kausik Ganguly
- Department of Genetics, University of Calcutta, Kolkata, India
| | - Tithi Dutta
- Department of Genetics, University of Calcutta, Kolkata, India
| | - Arpan Saha
- Department of Genetics, University of Calcutta, Kolkata, India
| | - Devroop Sarkar
- Joypur Block Primary Health Centre, Howrah, West Bengal, India
| | - Asim Sil
- Vivekananda Mission Ashram Netra Niramay Niketan, Purba Medinipur, West Bengal, India
| | - Kunal Ray
- ATGC Diagnostics, Kolkata, West Bengal, India
| | - Mainak Sengupta
- Department of Genetics, University of Calcutta, Kolkata, India
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Power B, Ferreira CR, Chen D, Zein WM, O'Brien KJ, Introne WJ, Stephen J, Gahl WA, Huizing M, Malicdan MCV, Adams DR, Gochuico BR. Hermansky-Pudlak syndrome and oculocutaneous albinism in Chinese children with pigmentation defects and easy bruising. Orphanet J Rare Dis 2019; 14:52. [PMID: 30791930 PMCID: PMC6385472 DOI: 10.1186/s13023-019-1023-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 02/04/2019] [Indexed: 11/28/2022] Open
Abstract
Background Determining the etiology of oculocutaneous albinism is important for proper clinical management and to determine prognosis. The purpose of this study was to genotype and phenotype eight adopted Chinese children who presented with oculocutaneous albinism and easy bruisability. Results The patients were evaluated at a single center; their ages ranged from 3 to 8 years. Whole exome or direct sequencing showed that two of the children had Hermansky-Pudlak syndrome (HPS) type-1 (HPS-1), one had HPS-3, one had HPS-4, and four had non-syndromic oculocutaneous albinism associated with TYR variants (OCA1). Two frameshift variants in HPS1 (c.9delC and c.1477delA), one nonsense in HPS4 (c.416G > A), and one missense variant in TYR (c.1235C > T) were unreported. The child with HPS-4 is the first case with this subtype reported in the Chinese population. Hypopigmentation in patients with HPS was mild compared to that in OCA1 cases, who had severe pigment defects. Bruises, which may be more visible in patients with hypopigmentation, were found in all cases with either HPS or OCA1. Whole mount transmission electron microscopy demonstrated absent platelet dense granules in the HPS cases; up to 1.9 mean dense granules per platelet were found in those with OCA1. Platelet aggregation studies in OCA1 cases were inconclusive. Conclusions Clinical manifestations of oculocutaneous albinism and easy bruisability may be observed in children with HPS or OCA1. Establishing definitive diagnoses in children presenting with these phenotypic features is facilitated by genetic testing. Non-syndromic oculocutaneous albinism and various HPS subtypes, including HPS-4, are found in children of Chinese ancestry.
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Affiliation(s)
- Bradley Power
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA
| | - Carlos R Ferreira
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA
| | - Dong Chen
- Division of Hematopathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Wadih M Zein
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kevin J O'Brien
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Wendy J Introne
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Joshi Stephen
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA
| | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA.,Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.,Undiagnosed Diseases Program, NIH Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD, USA
| | - Marjan Huizing
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA
| | - May Christine V Malicdan
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA.,Undiagnosed Diseases Program, NIH Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD, USA
| | - David R Adams
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA.,Undiagnosed Diseases Program, NIH Common Fund, Office of the Director, National Institutes of Health, Bethesda, MD, USA
| | - Bernadette R Gochuico
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, MSC 1851, Bethesda, MD, 20892-1851, USA.
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Darlington D, Puthanmadhom Narayanan S, Anitha FS. Synchronous Triple Malignancies in an Indian Albino: A Case Report. Cureus 2018; 10:e3190. [PMID: 30364818 PMCID: PMC6199145 DOI: 10.7759/cureus.3190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a heterogenous disorder of skin pigmentation characterized by hypopigmentation of the skin, hair, and eyes. The absence of melanin predisposes these individuals to ultraviolet rays induced malignancies. Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) in OCA have been rarely reported. Malignant melanoma (MM) of the skin is also very rarely reported. Synchronous BCC, SCC, and MM are exceedingly rare. We report one such case managed successfully with surgical treatment. All the three malignancies were localized cancers and hence the outcome was good. The importance of regular follow up and periodic self-examination in such predisposed individuals are highlighted.
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Affiliation(s)
- Danny Darlington
- Urology, Government Stanley Medical College And Hospital, Chennai, IND
| | - Susrutha Puthanmadhom Narayanan
- Bachelor of Medicine Bachelor of Surgery, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, IND
| | - Fatima Shirly Anitha
- Pediatrics, Church of South India Kalyani Multispeciality Hospital, Chennai , IND
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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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Sengupta M, Sarkar D, Mondal M, Samanta S, Sil A, Ray K. Analysis of MC1R variants in Indian oculocutaneous albinism patients: highlighting the risk of skin cancer among albinos. J Genet 2014; 92:305-8. [PMID: 23970088 DOI: 10.1007/s12041-013-0250-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Mainak Sengupta
- Molecular and Human Genetics Division, Council of Scientific and Industrial Research - Indian Institute of Chemical Biology, Kolkata 700 032, India
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Morice-Picard F, Lasseaux E, Cailley D, Gros A, Toutain J, Plaisant C, Simon D, François S, Gilbert-Dussardier B, Kaplan J, Rooryck C, Lacombe D, Arveiler B. High-resolution array-CGH in patients with oculocutaneous albinism identifies new deletions of theTYR, OCA2, andSLC45A2genes and a complex rearrangement of theOCA2gene. Pigment Cell Melanoma Res 2013; 27:59-71. [DOI: 10.1111/pcmr.12173] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 09/20/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Fanny Morice-Picard
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | | | | | - Audrey Gros
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
| | - Jérome Toutain
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
| | | | - Delphine Simon
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | - Stéphane François
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | | | - Josseline Kaplan
- Laboratoire de Génétique; CHU Paris -Hôpital Necker - Enfants Malades; Paris France
| | - Caroline Rooryck
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | - Didier Lacombe
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
| | - Benoit Arveiler
- Service de Génétique Médicale; CHU de Bordeaux; Bordeaux France
- Maladies Rares: Génétique et Métabolisme (MRGM) EA4576; Univ. Bordeaux; Bordeaux France
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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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Molecular basis of albinism in India: evaluation of seven potential candidate genes and some new findings. Gene 2012; 511:470-4. [PMID: 23010199 DOI: 10.1016/j.gene.2012.09.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 09/06/2012] [Accepted: 09/06/2012] [Indexed: 11/21/2022]
Abstract
Albinism represents a group of genetic disorders with a broad spectrum of hypopigmentary phenotypes dependent on the genetic background of the patients. Oculocutaneous albinism (OCA) patients have little or no pigment in their eyes, skin and hair, whereas ocular albinism (OA) primarily presents the ocular symptoms, and the skin and hair color may vary from near normal to very fair. Mutations in genes directly or indirectly regulating melanin production are responsible for different forms of albinism with overlapping clinical features. In this study, 27 albinistic individuals from 24 families were screened for causal variants by a PCR-sequencing based approach. TYR, OCA2, TYRP1, SLC45A2, SLC24A5, TYRP2 and SILV were selected as candidate genes. We identified 5 TYR and 3 OCA2 mutations, majority in homozygous state, in 8 unrelated patients including a case of autosomal recessive ocular albinism (AROA). A homozygous 4-nucleotide novel insertion in SLC24A5 was detected in a person showing with extreme cutaneous hypopigmentation. A potential causal variant was identified in the TYRP2 gene in a single patient. Haplotype analyses in the patients carrying homozygous mutations in the classical OCA genes suggested founder effect. This is the first report of an Indian AROA patient harboring a mutation in OCA2. Our results also reveal for the first time that mutations in SLC24A5 could contribute to extreme hypopigmentation in humans.
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Jaworek TJ, Kausar T, Bell SM, Tariq N, Maqsood MI, Sohail A, Ali M, Iqbal F, Rasool S, Riazuddin S, Shaikh RS, Ahmed ZM. Molecular genetic studies and delineation of the oculocutaneous albinism phenotype in the Pakistani population. Orphanet J Rare Dis 2012; 7:44. [PMID: 22734612 PMCID: PMC3537634 DOI: 10.1186/1750-1172-7-44] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 04/30/2012] [Indexed: 02/01/2023] Open
Abstract
Background Oculocutaneous albinism (OCA) is caused by a group of genetically heterogeneous inherited defects that result in the loss of pigmentation in the eyes, skin and hair. Mutations in the TYR, OCA2, TYRP1 and SLC45A2 genes have been shown to cause isolated OCA. No comprehensive analysis has been conducted to study the spectrum of OCA alleles prevailing in Pakistani albino populations. Methods We enrolled 40 large Pakistani families and screened them for OCA genes and a candidate gene, SLC24A5. Protein function effects were evaluated using in silico prediction algorithms and ex vivo studies in human melanocytes. The effects of splice-site mutations were determined using an exon-trapping assay. Results Screening of the TYR gene revealed four known (p.Arg299His, p.Pro406Leu, p.Gly419Arg, p.Arg278*) and three novel mutations (p.Pro21Leu, p.Cys35Arg, p.Tyr411His) in ten families. Ex vivo studies revealed the retention of an EGFP-tagged mutant (p.Pro21Leu, p.Cys35Arg or p.Tyr411His) tyrosinase in the endoplasmic reticulum (ER) at 37°C, but a significant fraction of p.Cys35Arg and p.Tyr411His left the ER in cells grown at a permissive temperature (31°C). Three novel (p.Asp486Tyr, p.Leu527Arg, c.1045-15 T > G) and two known mutations (p.Pro743Leu, p.Ala787Thr) of OCA2 were found in fourteen families. Exon-trapping assays with a construct containing a novel c.1045-15 T > G mutation revealed an error in splicing. No mutation in TYRP1, SLC45A2, and SLC24A5 was found in the remaining 16 families. Clinical evaluation of the families segregating either TYR or OCA2 mutations showed nystagmus, photophobia, and loss of pigmentation in the skin or hair follicles. Most of the affected individuals had grayish-blue colored eyes. Conclusions Our results show that ten and fourteen families harbored mutations in the TYR and OCA2 genes, respectively. Our findings, along with the results of previous studies, indicate that the p.Cys35Arg, p.Arg278* and p.Gly419Arg alleles of TYR and the p.Asp486Tyr and c.1045-15 T > G alleles of OCA2 are the most common causes of OCA in Pakistani families. To the best of our knowledge, this study represents the first documentation of OCA2 alleles in the Pakistani population. A significant proportion of our cohort did not have mutations in known OCA genes. Overall, our study contributes to the development of genetic testing protocols and genetic counseling for OCA in Pakistani families.
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Affiliation(s)
- Thomas J Jaworek
- Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
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A hypothesis to explain the high prevalence of pseudo-cholinesterase deficiency in specific population groups. Eur J Anaesthesiol 2011; 28:550-2. [PMID: 21734504 DOI: 10.1097/eja.0b013e3283457cfb] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Molecular and functional studies of tyrosinase variants among Indian oculocutaneous albinism type 1 patients. J Invest Dermatol 2010; 131:260-2. [PMID: 20861851 DOI: 10.1038/jid.2010.274] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Sengupta M, Mondal M, Jaiswal P, Sinha S, Chaki M, Samanta S, Ray K. Comprehensive analysis of the molecular basis of oculocutaneous albinism in Indian patients lacking a mutation in the tyrosinase gene. Br J Dermatol 2010; 163:487-94. [PMID: 20426782 DOI: 10.1111/j.1365-2133.2010.09830.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Oculocutaneous albinism (OCA) refers to a group of inherited disorders where the patients have little or no pigment in the eyes, skin and hair. Mutations in genes regulating multi-step melanin biosynthesis are the basis of four 'classical' OCA types with overlapping clinical features. There are a few reports on defects in TYR and a single report on SLC45A2 in Indians affected with OCA but no report on OCA2 (a major locus related to the disease) and TYRP1. OBJECTIVES To assess and describe a comprehensive picture of the molecular genetic basis of OCA among Indians with no apparent mutations in TYR. METHODS Twenty-four affected pedigrees from 14 different ethnicities were analysed for mutations in OCA2, TYRP1, SLC45A2 and SLC24A5 using the polymerase chain reaction-sequencing approach. RESULTS Two splice-site and four missense mutations were detected in OCA2 in seven unrelated pedigrees, including four novel mutations. Haplotype analysis revealed a founder mutation (Ala787Thr) in two unrelated families of the same ethnicity. A patient homozygous for a novel SLC45A2 mutation also harboured a novel OCA2 defect. No mutation was detected in TYRP1 or SLC24A5. CONCLUSIONS Our results suggest that an OCA2 gene defect is the second most prevalent type of OCA in India after TYR. The presence of homozygous mutations in the affected pedigrees underscores the lack of intermixing between the affected ethnicities. Direct detection of the genetic lesions prevalent in specific ethnic groups could be used for carrier detection and genetic counselling to contain the disease.
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Affiliation(s)
- M Sengupta
- Division of Molecular and Human Genetics, Indian Institute of Chemical Biology (a CSIR unit), 4 Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
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Ray K, Chaki M, Sengupta M. Tyrosinase and ocular diseases: Some novel thoughts on the molecular basis of oculocutaneous albinism type 1. Prog Retin Eye Res 2007; 26:323-58. [PMID: 17355913 DOI: 10.1016/j.preteyeres.2007.01.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Tyrosinase (TYR) is a multifunctional copper-containing glycoenzyme (approximately 80 kDa), which plays a key role in the rate-limiting steps of the melanin biosynthetic pathway. This membrane-bound protein, possibly evolved by the fusion of two different copper-binding proteins, is mainly expressed in epidermal, ocular and follicular melanocytes. In the melanocytes, TYR functions as an integrated unit with other TYR-related proteins (TYRP1, TYRP2), lysosome-associated membrane protein 1 (LAMP1) and melanocyte-stimulating hormone receptors; thus forming a melanogenic complex. Mutations in the TYR gene (TYR, 11q14-21, MIM 606933) cause oculocutaneous albinism type 1 (OCA1, MIM 203100), a developmental disorder having an autosomal recessive mode of inheritance. In addition, TYR can act as a modifier locus for primary congenital glaucoma (PCG) and it also contributes significantly in the eye developmental process. Expression of TYR during neuroblast division helps in later pathfinding by retinal ganglion cells from retina to the dorsal lateral geniculate nucleus. However, mutation screening of TYR is complicated by the presence of a pseudogene-TYR like segment (TYRL, 11p11.2, MIM 191270), sharing approximately 98% sequence identity with the 3' region of TYR. Thus, in absence of a full-proof strategy, any nucleotide variants identified in the 3' region of TYR could actually be present in TYRL. Interestingly, despite extensive search, the second TYR mutation in 15% of the OCA1 cases remains unidentified. Several possible locations of these "uncharacterized mutations" (UCMs) have been speculated so far. Based on the structure of TYR gene, its sequence context and some experimental evidences, we propose two additional possibilities, which on further investigations might shed light on the molecular basis of UCMs in TYR of OCA1 patients; (i) partial deletion of the exons 4 and 5 region of TYR that is homologous with TYRL and (ii) variations in the polymorphic GA complex repeat located between distal and proximal elements of the human TYR promoter that can modulate the expression of the gene leading to disease pathogenesis.
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Affiliation(s)
- Kunal Ray
- Molecular and Human Genetics Division, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India.
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