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Dotson AD, Fingert JH, Boese EA. Unsuccessful transscleral cyclophotocoagulation in oculocutaneous albinism. Am J Ophthalmol Case Rep 2024; 34:102020. [PMID: 38404485 PMCID: PMC10884796 DOI: 10.1016/j.ajoc.2024.102020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 02/04/2024] [Accepted: 02/14/2024] [Indexed: 02/27/2024] Open
Abstract
Purpose To report a case of unsuccessful transscleral cyclophotocoagulation in a patient with OCA1A tyrosinase-negative oculocutaneous albinism. Observations A 35-year-old Asian female with molecularly diagnosed OCA1A (tyrosinase-negative) oculocutaneous albinism and unilateral severe mixed mechanism glaucoma underwent transscleral cyclophotocoagulation on two separate occasions to treat elevated intraocular pressure. The intraocular pressure remained markedly elevated approximately 1 month following two separate treatments of transscleral cyclophotocoagulation while using high energy settings. The poor efficacy of both cyclophotocoagulation treatments was most likely due to a lack of melanin in the setting of oculocutaneous albinism. Conclusions and importance Cyclophotocoagulation in patients with oculocutaneous albinism is less likely to yield a desired lowering of intraocular pressure due to the absence of melanin.
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Affiliation(s)
- Aaron D. Dotson
- Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, USA
| | - John H. Fingert
- Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, USA
- Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Erin A. Boese
- Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, USA
- Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, USA
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2
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Brown AR, Comai K, Mannino D, McCullough H, Donekal Y, Meyers HC, Graves CW, Seidel HS. A community-science approach identifies genetic variants associated with three color morphs in ball pythons (Python regius). PLoS One 2022; 17:e0276376. [PMID: 36260636 PMCID: PMC9581371 DOI: 10.1371/journal.pone.0276376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 10/05/2022] [Indexed: 11/13/2022] Open
Abstract
Color morphs in ball pythons (Python regius) provide a unique and largely untapped resource for understanding the genetics of coloration in reptiles. Here we use a community-science approach to investigate the genetics of three color morphs affecting production of the pigment melanin. These morphs-Albino, Lavender Albino, and Ultramel-show a loss of melanin in the skin and eyes, ranging from severe (Albino) to moderate (Lavender Albino) to mild (Ultramel). To identify genetic variants causing each morph, we recruited shed skins of pet ball pythons via social media, extracted DNA from the skins, and searched for putative loss-of-function variants in homologs of genes controlling melanin production in other vertebrates. We report that the Albino morph is associated with missense and non-coding variants in the gene TYR. The Lavender Albino morph is associated with a deletion in the gene OCA2. The Ultramel morph is associated with a missense variant and a putative deletion in the gene TYRP1. Our study is one of the first to identify genetic variants associated with color morphs in ball pythons and shows that pet samples recruited from the community can provide a resource for genetic studies in this species.
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Affiliation(s)
- Autumn R. Brown
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Kaylee Comai
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Dominic Mannino
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Haily McCullough
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Yamini Donekal
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Hunter C. Meyers
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
| | - Chiron W. Graves
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
- * E-mail: (CWG); (HSS)
| | - Hannah S. Seidel
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
- * E-mail: (CWG); (HSS)
| | - The BIO306W Consortium
- Department of Biology, Eastern Michigan University, Ypsilanti, MI, United States of America
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3
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Xu C, Xiang Y, Li H, Xu Y, Mao Y, Zhou L, Xu X, Tang S. Genetic analysis and prenatal diagnosis of 20 Chinese families with oculocutaneous albinism. J Clin Lab Anal 2020; 35:e23647. [PMID: 33124154 PMCID: PMC7891544 DOI: 10.1002/jcla.23647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 12/27/2022] Open
Abstract
Background Oculocutaneous albinism (OCA) is a group of heterogeneous genetic disorders characterized by abnormal melanin synthesis in the hair, skin, and eyes. OCA exhibits obvious genetic and phenotypic heterogeneity. Molecular diagnosis of causal genes can be of help in the classification of OCA subtypes and the study of OCA pathogenesis. Methods In this study, Sanger sequencing and whole exome sequencing were used to genetically diagnose 20 nonconsanguineous Chinese OCA patients. In addition, prenatal diagnosis was provided to six OCA families. Results Variants of TYR, OCA2, and HPS1 were detected in 85%, 10%, and 5% of affected patients, respectively. A total of 21 distinct variants of these three genes were identified. Exons 1 and 2 were the hotspot regions of the TYR variants, and c.895C > A and c.896G > A were the hotspot variants. We also found seven novel variants: c.731G > A, c.741C > A, c.867C > A, and c.1037‐2A > T in TYR, c.695dupT and c.1054A > G in OCA2, and c.9C > A in HPS1. Genetic tests on six fetuses revealed three carrier fetuses, two normal fetuses, and one affected fetus. The follow‐up results after birth were consistent with the results of prenatal diagnosis (one fetus terminated during pregnancy was not followed up). Conclusions This study expands our understanding of the genotypic spectrum of the Chinese OCA population. The findings indicate that prenatal diagnosis can provide important information for genetic counseling.
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Affiliation(s)
- Chenyang Xu
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Yanbao Xiang
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Huanzheng Li
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Yunzhi Xu
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Yijian Mao
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Lili Zhou
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Xueqin Xu
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China
| | - Shaohua Tang
- Key Laboratory of Birth Defects, Department of Genetics, Wenzhou Central Hospital, Wenzhou, China.,Key Laboratory of Medical Genetic, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, China
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Luo D, Linpeng S, Zeng L, Tan H, Li Z, Wu L. Molecular genetic study of 59 Chinese Oculocutaneous albinism families. Eur J Med Genet 2019; 62:103709. [PMID: 31229681 DOI: 10.1016/j.ejmg.2019.103709] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 04/24/2019] [Accepted: 06/19/2019] [Indexed: 12/11/2022]
Abstract
Oculocutaneous albinism is an autosomal recessive disorder characterized by either a complete lack of or reduction in melanin biosynthesis in the skin, hair, and eyes. The aim of the present study was to identify the molecular basis for 59 Chinese OCA families. In this study, compound heterozygous or homozygous pathogenic variants were found in 53 families, 4 families possessed only one heterozygous variant, and the pathogenic variants of 2 families remain undiscovered by using Sanger sequencing, whole exome sequencing and multiplex ligation-dependent probe amplification. We have identified a total of 55 variants including 21 novel variants in TYR, OCA2, SLC45A2, SLC24A5, and HPS1. The 21 novel variants include 11 missense changes, 4 nonsense changes, 2 splice site changes, 1 frameshift and 3 gross deletions. Forty-six variants including 14 novel variants were segregated with the phenotype in 37 families. We conducted RT-PCR of the novel splicing site variant (c.399-14G > A) of HPS1 and verified that the variant would result in the inclusion of 12 bp of intronic material in exon 6 of HPS1. The results of platelet whole mount electron microscopy further confirmed the diagnosis of HPS1. These novel variants identified in our study expand the mutational spectrum of the disease, which contributes to prenatal diagnosis and genetic counselling.
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Affiliation(s)
- Dan Luo
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Siyuan Linpeng
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Lanlan Zeng
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Hu Tan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Zhuo Li
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Lingqian Wu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.
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5
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Lin Y, Chen X, Yang Y, Che F, Zhang S, Yuan L, Wu Y. Mutational Analysis of TYR, OCA2, and SLC45A2 Genes in Chinese Families with Oculocutaneous Albinism. Mol Genet Genomic Med 2019; 7:e00687. [PMID: 31199599 PMCID: PMC6625147 DOI: 10.1002/mgg3.687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 02/24/2019] [Accepted: 03/06/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a group of heterogeneous autosomal recessive genetic disorder of melanin synthesis results in hypopigmented hair, skin, and eyes. OCA type 1, OCA type 2, and OCA type 4, which are respectively caused by mutations in TYR, OCA2, and SLC45A2 have high morbidity rates in Asia. METHODS TYR, OCA2, and SLC45A2 mutation analysis was carried out on 18 nonconsanguineous OCA patients and four fetuses were included for prenatal diagnose. Three genes of all individuals were amplified by polymerase chain reaction and examined by Sanger sequencing. The pathogenicity of the detected mutations were analyzed by Mutation Taster, PolyPhen 2, and SIFT software, and the conservation of the substituted amino acids were analyzed by MEGA software. RESULTS Eleven TYR mutations, three OCA2 mutations, and two SLC45A2 mutations were identified in 14 OCA type 1 patients, two OCA type 2 patients, and two OCA type 4 patients. c.1021A>G, p.R341G in TYR, c.1096_1104del, p.V366*, and c.1079C>T, p.S360F in OCA2 were novel. One of the four fetuses carried compound heterozygous mutation of TYR and became spontaneous abortion, the other three carried no mutations and appeared normal at birth. CONCLUSION In this study, specific clinical characteristics of OCA patients were described. Three novel pathogenic mutations were identified which will enrich the mutation spectrum of OCA, and the prenatal genetic screening in fetus at risk of OCA can provide vital information for genetic counseling.
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Affiliation(s)
- Ye Lin
- The General Hospital of the People's Liberation Army, Beijing, P.R. China
| | - Xihui Chen
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China
| | - Ying Yang
- Shaanxi Institute of Pediatric Diseases, Xi'an Children's Hospital, Xi'an, Shaanxi, P.R. China
| | - Fengyu Che
- Shaanxi Institute of Pediatric Diseases, Xi'an Children's Hospital, Xi'an, Shaanxi, P.R. China
| | - Sijia Zhang
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China
| | - Lijuan Yuan
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China.,Department of General Surgery, Tangdu Hospital, Air Force Medical University, Xi'an, Shaanxi, P.R. China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, Air Force Medical University, Xi'an, Shaanxi, P.R. China
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6
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Yang Q, Yi S, Li M, Xie B, Luo J, Wang J, Rong X, Zhang Q, Qin Z, Hang L, Feng S, Fan X. Genetic analyses of oculocutaneous albinism types 1 and 2 with four novel mutations. BMC MEDICAL GENETICS 2019; 20:106. [PMID: 31196117 PMCID: PMC6567650 DOI: 10.1186/s12881-019-0842-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 06/04/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a human autosomal-recessive hypopigmentation disorder with hypopigmentation in the skin, hair, and eyes. OCA1 and OCA2 are caused by mutations of the TYR and OCA2 genes, respectively, which are responsible for most oculocutaneous albinism. However, the incidence of oculocutaneous albinism patients in Guangxi remains unclear. METHODS To evaluate the molecular basis of oculocutaneous albinism in thirty-six patients in Guangxi, China. Peripheral venous blood samples were collected from these unrelated patients. The TYR and OCA2 genes of all individuals were analyzed by direct DNA sequencing and the sequences compared with are reference database and bioinformatics analysis. RESULTS Among the 36 OCA patients, 8(22.2%) were found mutations on TYR gene, 28 (77.8%) on OCA2. And we identified Twenty-seven different TYR and OCA2 mutations in these patients, including one novel TYR framshift mutation c.561_562insTTATTATGTGTCAAATTATCCCCCA, three novel OCA2 mutations: one nonsense mutation c.2195C > G(p.S732X), one deletation mutation(c.1139-1141delTGG), one missense mutations c.2495A > C(p.H832P). The population screening and the bioinformatic analysis to determined the effects of the mutations, which revealed these four novel mutations were pathogenic. CONCLUSIONS This study expands the mutation spectrum of oculocutaneous albinism. Four novel mutational alleles c.1139-1141delTGG, c.1832 T > C and c.2195C > G and of the OCA2 gene and c.561_562insTTATTATGTGTCAAATTATCCCCCA of TYR were associated with OCA. The genotype-phenotype correlations suggest that molecular diagnosis is more accurate and important in OCA.
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Affiliation(s)
- Qi Yang
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Sheng Yi
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Mengting Li
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Bobo Xie
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Jinsi Luo
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Jin Wang
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Xiuliang Rong
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Qinle Zhang
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Zailong Qin
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Limei Hang
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Shihan Feng
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
| | - Xin Fan
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, No.59, Xiangzhu Road, Nanning, China
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7
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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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Sun W, Shen Y, Shan S, Han L, Li Y, Zhou Z, Zhong Z, Chen J. Identification of TYR mutations in patients with oculocutaneous albinism. Mol Med Rep 2018; 17:8409-8413. [PMID: 29658579 DOI: 10.3892/mmr.2018.8881] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 08/01/2017] [Indexed: 11/06/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a set of autosomal recessive disorders characterized by hypopigmented hair, skin and eyes. Homozygous or compound heterozygous mutations in the tyrosinase (TYR) gene can cause OCA1, which is the most common and severe subtype of albinism. In the present study, 17 patients with non‑syndromic OCA were enrolled from eight provinces of China and were non‑consanguineous, with the exception of Patient 4000301. Total genomic DNA was isolated from peripheral blood. Screening was performed for the whole exons and their flanking regions of the TYR gene using Sanger sequencing and the pathogenicity of variants was predicted using in silico analysis. In total, 12 TYR mutations were identified in 10 patients, respectively. Of these, two patients carried homozygous mutations and eight patients carried compound heterozygous mutations. Among the 12 TYR mutations, two missense mutations c.1198T>G (p.W400G) and c.819G>T (p.Q273H) were novel. The results of the present study expand the mutation spectrum of the TYR gene, which may further assist in the prenatal examination and genetic diagnosis of OCA.
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Affiliation(s)
- Wan Sun
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai 200092, P.R. China
| | - Yanjie Shen
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai 200092, P.R. China
| | - Shan Shan
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Liyun Han
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai 200092, P.R. China
| | - Yang Li
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai 200092, P.R. China
| | - Zheng Zhou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Zilin Zhong
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai 200092, P.R. China
| | - Jianjun Chen
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji Eye Institute, Tongji University School of Medicine, Shanghai 200092, P.R. China
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9
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Qiu B, Ma T, Peng C, Zheng X, Yang J. Identification of Five Novel Variants in Chinese Oculocutaneous Albinism by Targeted Next-Generation Sequencing. Genet Test Mol Biomarkers 2018; 22:252-258. [PMID: 29437493 DOI: 10.1089/gtmb.2017.0211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The diagnosis of oculocutaneous albinism (OCA) is established using clinical signs and symptoms. OCA is, however, a highly genetically heterogeneous disease with mutations identified in at least nineteen unique genes, many of which produce overlapping phenotypic traits. Thus, differentiating genetic OCA subtypes for diagnoses and genetic counseling is challenging, based on clinical presentation alone, and would benefit from a comprehensive molecular diagnostic. AIM To develop and validate a more comprehensive, targeted, next-generation-sequencing-based diagnostic for the identification of OCA-causing variants. MATERIALS AND METHODS The genomic DNA samples from 28 OCA probands were analyzed by targeted next-generation sequencing (NGS), and the candidate variants were confirmed through Sanger sequencing. RESULTS We observed mutations in the TYR, OCA2, and SLC45A2 genes in 25/28 (89%) patients with OCA. We identified 38 pathogenic variants among these three genes, including 5 novel variants: c.1970G>T (p.Gly657Val), c.1669A>C (p.Thr557Pro), c.2339-2A>C, and c.1349C>G (p.Thr450Arg) in OCA2; c.459_470delTTTTGCTGCCGA (p.Ala155_Phe158del) in SLC45A2. CONCLUSION Our findings expand the mutational spectrum of OCA in the Chinese population, and the assay we developed should be broadly useful as a molecular diagnostic, and as an aid for genetic counseling for OCA patients.
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Affiliation(s)
- Biyuan Qiu
- 1 Medical Technology College, Chengdu University of Traditional Chinese Medicine of China , Chengdu, Sichuan, P.R. China
| | - Tao Ma
- 2 Prenatal Diagnosis Center, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital , Chengdu, Sichuan, P.R. China .,3 Department of Gynecology & Obstetrics, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital , Chengdu, Sichuan, P.R. China
| | - Chunyan Peng
- 4 School of Medicine, University of Electronic Science and Technology of China , Chengdu, Sichuan, P.R. China
| | - Xiaoqin Zheng
- 1 Medical Technology College, Chengdu University of Traditional Chinese Medicine of China , Chengdu, Sichuan, P.R. China
| | - Jiyun Yang
- 2 Prenatal Diagnosis Center, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital , Chengdu, Sichuan, P.R. China .,4 School of Medicine, University of Electronic Science and Technology of China , Chengdu, Sichuan, P.R. China .,5 Sichuan Provincial Key Laboratory for Human Disease Gene Study, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital , Chengdu, Sichuan, P.R. China
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10
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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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Abstract
Oculocutaneous albinism (OCA) is a heterogeneous autosomal recessive genetic disorder that affects melanin synthesis. OCA results in reduced or absent pigmentation in the hair, skin and eyes. Type 1 OCA (OCA1) is the result of tyrosinase (TYR) gene mutations and is a severe disease type. This study investigated TYR mutations in a Chinese cohort with OCA1. This study included two parts: patient genetic study and prenatal genetic diagnosis. A total of 30 OCA1 patients were subjected to TYR gene mutation analysis. Ten pedigrees were included for prenatal genetic diagnosis. A total of 100 unrelated healthy Chinese individuals were genotyped for controls. The coding sequence and the intron/exon junctions of TYR were analysed by bidirectional DNA sequencing. In this study, 20 mutations were identified, four of which were novel. Of these 30 OCA1 patients, 25 patients were TYR compound heterozygous; two patients carried homozygous TYR mutations; and three were heterozygous. Among the ten prenatally genotyped fetuses, three fetuses carried compound heterozygous mutations and seven carried no mutation or only one mutant allele of TYR and appeared normal at birth. In conclusion, we identified four novel TYR mutations and showed that molecular-based prenatal screening to detect TYR mutations in a fetus at risk for OCA1 provided essential information for genetic counselling of couples at risk.
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Wei A, Wang Y, Long Y, Wang Y, Guo X, Zhou Z, Zhu W, Liu J, Bian X, Lian S, Li W. A Comprehensive Analysis Reveals Mutational Spectra and Common Alleles in Chinese Patients with Oculocutaneous Albinism. J Invest Dermatol 2010; 130:716-24. [DOI: 10.1038/jid.2009.339] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Liu J, Choy KW, Chan LWL, Leung TY, Tam POS, Chiang SWY, Lam DSC, Pang CP, Lai TYY. Tyrosinase gene (TYR) mutations in Chinese patients with oculocutaneous albinism type 1. Clin Exp Ophthalmol 2010; 38:37-42. [DOI: 10.1111/j.1442-9071.2009.02220.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Chaki M, Mukhopadhyay A, Ray K. Determination of variants in the 3'-region of the tyrosinase gene requires locus specific amplification. Hum Mutat 2006; 26:53-8. [PMID: 15895460 DOI: 10.1002/humu.20171] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mutations in the Tyrosinase gene (TYR, 11q14-q21) cause oculocutaneous albinism type 1 (OCA1). The 3'-region of the TYR shows 98.55% sequence identity with a pseudogene, known as Tyrosinase-Like Gene (TYRL, 11p11.2-cen). A large number of publicly available nucleotide variants of TYR in this region are same as the bases present in the identical locations in the pseudogene. PCR amplification of these regions using primers with sequences common to both loci may result in coamplification of TYR and TYRL, and may lead to misinterpretation of the results. We have resolved this potential problem using locus-specific amplification conditions that could be used to identify unequivocally mutations and SNPs in exon 4 and exon 5 of TYR and proximal flanking sequences.
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Affiliation(s)
- Moumita Chaki
- Human Genetics and Genomics Division, Indian Institute of Chemical Biology, Kolkata, India
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Hsieh YY, Wu JY, Chang CC, Tsai FJ, Lee CC, Tsai HD, Tsai CH. Prenatal diagnosis of oculocutaneous albinism two mutations located at the same allele. Prenat Diagn 2001. [DOI: 10.1002/1097-0223(200103)21:3<200::aid-pd31>3.0.co;2-j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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