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Ang KC, Canfield VA, Foster TC, Harbaugh TD, Early KA, Harter RL, Reid KP, Leong SL, Kawasawa Y, Liu D, Hawley JW, Cheng KC. Native American genetic ancestry and pigmentation allele contributions to skin color in a Caribbean population. eLife 2023; 12:e77514. [PMID: 37294081 PMCID: PMC10371226 DOI: 10.7554/elife.77514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/08/2023] [Indexed: 06/10/2023] Open
Abstract
Our interest in the genetic basis of skin color variation between populations led us to seek a Native American population with genetically African admixture but low frequency of European light skin alleles. Analysis of 458 genomes from individuals residing in the Kalinago Territory of the Commonwealth of Dominica showed approximately 55% Native American, 32% African, and 12% European genetic ancestry, the highest Native American genetic ancestry among Caribbean populations to date. Skin pigmentation ranged from 20 to 80 melanin units, averaging 46. Three albino individuals were determined to be homozygous for a causative multi-nucleotide polymorphism OCA2NW273KV contained within a haplotype of African origin; its allele frequency was 0.03 and single allele effect size was -8 melanin units. Derived allele frequencies of SLC24A5A111T and SLC45A2L374F were 0.14 and 0.06, with single allele effect sizes of -6 and -4, respectively. Native American genetic ancestry by itself reduced pigmentation by more than 20 melanin units (range 24-29). The responsible hypopigmenting genetic variants remain to be identified, since none of the published polymorphisms predicted in prior literature to affect skin color in Native Americans caused detectable hypopigmentation in the Kalinago.
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Affiliation(s)
- Khai C Ang
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Victor A Canfield
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Tiffany C Foster
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Thaddeus D Harbaugh
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Kathryn A Early
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Rachel L Harter
- Department of Pathology, Penn State College of MedicineHersheyUnited States
| | - Katherine P Reid
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
| | - Shou Ling Leong
- Department of Family & Community Medicine, Penn State College of MedicineHersheyUnited States
| | - Yuka Kawasawa
- Department of Biochemistry and Molecular Biology, Penn State College of MedicineHersheyUnited States
- Department of Pharmacology, Penn State College of MedicineHersheyUnited States
- Institute of Personalized Medicine, Penn State College of MedicineHersheyUnited States
| | - Dajiang Liu
- Department of Biochemistry and Molecular Biology, Penn State College of MedicineHersheyUnited States
- Department of Public Health Sciences, Penn State College of MedicineHersheyUnited States
| | | | - Keith C Cheng
- Department of Pathology, Penn State College of MedicineHersheyUnited States
- Jake Gittlen Laboratories for Cancer Research, Penn State College of MedicineHersheyUnited States
- Department of Biochemistry and Molecular Biology, Penn State College of MedicineHersheyUnited States
- Department of Pharmacology, Penn State College of MedicineHersheyUnited States
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Chen X, Fang Z, Pang T, Li D, Lei J, Jiang W, Li H. Identification of novel variations of oculocutaneous albinism type 2 with Prader-Willi syndrome/Angelman syndrome in two Chinese families. Front Genet 2023; 14:1135698. [PMID: 36950135 PMCID: PMC10025288 DOI: 10.3389/fgene.2023.1135698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/15/2023] [Indexed: 03/08/2023] Open
Abstract
Objective: Oculocutaneous albinism (OCA) is an autosomal recessive disorder caused by a variety of genomic variations. Our aim is to identify the molecular basis of OCA in two families and lay the foundation for prenatal diagnosis. Methods: Four types of OCA-causing mutations in the TYR, p, TYRP1, or SLC45A2 genes were screened. Linkage analysis was performed because the mutations found in the p gene violated the laws of classical Mendelian heredity. Primer-walking sequencing combined with microsatellite and single-nucleotide polymorphism analysis was used to ascertain deletion ranges. Bioinformatics methods were used to assess the pathogenicity of the new mutations. Results: Proband 1 was diagnosed as OCA2 with Prader-Willi syndrome (PWS) due to a novel atypical paternal deletion (chromosome 15: 22330347-26089649) and a pathogenic mutation, c.1327G>A (Val443Ile), in the p gene of the maternal chromosome. The prenatal diagnosis results for family 1 indicated the fetus was a heterozygous carrier (c.1327G>A in the p gene) with a normal phenotype. Proband 2 was diagnosed as OCA2 with Angelman syndrome (AS) due to a typical maternal deletion of chromosome 15q11-q13 and a novel mutation, c.1514T>C (Phe505Ser), in the p gene of the paternal chromosome. This novel mutation c.1514T>C (Phe505Ser) in the p gene was predicted as a pathogenic mutation. Conclusion: Our study has shown clear genotype-phenotype correlations in patients affected by distinct deletions of the PWS or AS region and missense mutations in the p gene. Our results have enriched the mutation spectrum of albinism diseases and provided insights for more accurate diagnosis and genetic counseling.
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Affiliation(s)
- XiaoFei Chen
- Maternity and Child Care Center of Dezhou, DeZhou, China
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
| | - ZiShui Fang
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- Beijing Key Laboratory of Urogenital Diseases (Male) Molecular Diagnosis and Treatment Center, National Urological Cancer Center, Department of Urology, Peking University First Hospital, Institution of Urology, Peking University, Beijing, China
| | - Ting Pang
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
| | - DongZhi Li
- Prenatal Diagnosis Center, Guangzhou Women and Children’s Medical Center, Guangzhou, China
| | - Jie Lei
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- Shenzhen Nanshan Maternity and Child Healthcare Hospital, Shenzhen, China
- *Correspondence: Jie Lei, ; WeiYing Jiang, ; HongYi Li,
| | - WeiYing Jiang
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- *Correspondence: Jie Lei, ; WeiYing Jiang, ; HongYi Li,
| | - HongYi Li
- Department of Medical Genetics, Zhongshan School of Medicine, Guangzhou, China
- *Correspondence: Jie Lei, ; WeiYing Jiang, ; HongYi Li,
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Bhate M, Lalwani S, Chakrabarti S. Phenotypic variations in ocular features among siblings with oculocutaneous albinism. Indian J Ophthalmol 2022; 70:2511-2515. [PMID: 35791147 PMCID: PMC9426174 DOI: 10.4103/ijo.ijo_1025_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Purpose: To assess the clinical profiles, presenting ocular features, and variations in the phenotypic features in siblings with oculocutaneous albinism (OCA). Methods: Electronic medical records of consecutive siblings diagnosed with albinism from January 2016 to December 2020 were reviewed to identify the affected siblings. The variations in their phenotypic characteristics were studied. Results: Significant variations were observed in the clinical features between the siblings (n = 42). A difference of >2 lines in visual acuity was observed in 50% (n = 21) of the sibling pairs. Compound hyperopic astigmatism was the commonest refractive error. The refractive status was different in 80.95% (n = 34) pairs. Although individually strabismus and abnormal head posture were observed in one-third and one-fourth of individual children, respectively, both siblings with similar strabismus were seen in only 16.67% (n = 7) and with a similar abnormal head posture in 13.33% (n = 5). Nystagmus was the most consistent finding across these siblings with a similar nature of horizontal jerk or pendular in 65% of sibling pairs. Conclusion: This study observed significant variations in phenotypic presentations among siblings with OCA. Such differences in clinical manifestations and severity would be helpful in appropriate counseling of these families as the need for rehabilitation services is likely to vary across siblings.
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Affiliation(s)
- Manjushree Bhate
- Strabismus, Pediatric and Neuro-Ophthalmology, Jasti V. Ramanamma Children's Eye Care Centre, L.V. Prasad Eye Institute, Hyderabad, Telangana, India
| | - Sakshi Lalwani
- Strabismus, Pediatric and Neuro-Ophthalmology, Jasti V. Ramanamma Children's Eye Care Centre, L.V. Prasad Eye Institute, Hyderabad, Telangana, India
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Xiao Y, Zhou C, Xie H, Huang S, Wang J, Liu S. NGS-based targeted sequencing identified two novel variants in Southwestern Chinese families with oculocutaneous albinism. BMC Genomics 2022; 23:332. [PMID: 35488210 PMCID: PMC9055679 DOI: 10.1186/s12864-022-08597-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Oculocutaneous albinism (OCA) is a group of heterogeneous genetic diseases characterized by a reduction or complete lack of pigmentation in the hair, skin, and eyes. It is associated with reduced visual acuity, nystagmus, photophobia, and strabismus. OCA type 1 (OCA1) and type 2 (OCA2) are caused by mutations in the tyrosinase (TYR) and OCA2 genes, which are responsible for most cases of OCA. The present study aimed to identify the mutational spectra of 18 southwest Chinese probands with OCA. RESULTS We used a skin disease-targeted panel to sequence more than 400 genes, including 23 genes (TYR, OCA2, AP3B1, BLOC1S3, BLOC1S6, C10orf11, DTNBP1, FRMD7, GPR143, HPS1, HPS3, HPS4, HPS5, HPS6, LYST, MC1R, MITF, MLPH, MYO5A, RAB27A, SLC24A5, SLC45A2, TYRP1) associated with syndromic and non-syndromic albinism. The targeted panel was applied to 18 patients from southwest China, nine (50%) patients were diagnosed with OCA1, and nine (50%) were diagnosed with OCA2. Our data indicate that OCA1 and OCA2, the most common subtypes, probably have the same prevalence in southwest China. In total, we identified 26 variants in TYR and OCA2 from 18 OCA cases using the NGS technology, including 24 variants presented in the Human Gene Mutation Database Professional (HGMD) and two novel variants, c.559_560insCATTATTATGTGTCAAATTATCCCC in TYR and c.1514 T > C in OCA2, which have not been previously reported. According to the American College of Medical Genetics and Genomics (ACMG) classification, c.559_560insCATTATTATGTGTCAAATTATCCCC (p.G190Cfs*12) is classified as a pathogenic variant, and c.1514 T > C (p.F505S) is evaluated as a likely pathogenic variant. CONCLUSIONS Two novel variants were identified which will expand the mutational spectra of TYR and OCA2. The results of the present study may have implications for genetic counseling, carrier screening, and clinical management of the disease.
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Affiliation(s)
- Yuanyuan Xiao
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Cong Zhou
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Hanbing Xie
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Shuang Huang
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China
| | - Jing Wang
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China. .,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China.
| | - Shanling Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital of Sichuan University, Chengdu, 610041, China. .,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, 610041, China.
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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: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Ma L, Zhu J, Wang J, Huang Y, Zhang J, Wang C, Zhou Y, Peng D. Genetic Analysis of 28 Chinese Families With Tyrosinase-Positive Oculocutaneous Albinism. Front Genet 2021; 12:715437. [PMID: 34707637 PMCID: PMC8544823 DOI: 10.3389/fgene.2021.715437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/30/2021] [Indexed: 11/28/2022] Open
Abstract
Background Tyrosinase-positive oculocutaneous albinism (OCA, type II, OCA2) is an autosomal recessive genetic disease in which the biosynthesis of melanin decreases in the skin, hair, and eyes. OCA2 disease is caused by mutations in OCA2 gene. The gene product plays a role in regulating the pH of melanosomes. Up to now, hundreds of OCA2 mutations have been reported and novel variants are still being discovered. Methods In this study, we reviewed the records of OCA2 patients who had conducted albinism genetic testing, and then analyzed the clinical and genetic information of 28 OCA2 patients who had been genetically diagnosed by using Sanger sequencing and next-generation sequencing. Results In this study, we reported 31 variants screened from 28 Chinese OCA2 families, and characterized the detailed molecular and clinical presentations. There were 12 novel variants among all detected variants, including 3 missense variants (p.G393V, p.T482A, and p.R720P), 4 frameshift variants (p.R53Gfs∗49, p.N279Kfs∗17, p.I469Lfs∗4, p.I655Nfs∗12), 2 splicing variants (c.1637-2A > G, c.1951 + 1G > C), 2 stopgain variants (p.L278X, p.W652X) and 1 insertion variants (p.P315LinsT). One potential cluster of missense variants was implicated indicating the important roles of the underlying domains in OCA2 pathogenesis. Conclusion Our results were beneficial for diagnosis and precision clinical management for OCA2-related disorder, and this study expanded the mutation spectrum of oculocutaneous albinism.
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Affiliation(s)
- Linya Ma
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jianjian Zhu
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jing Wang
- Changsha Kingmed Center for Clinical Laboratory, Changsha, China
| | - Yazhou Huang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Jibo Zhang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Chao Wang
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Yuan Zhou
- Department of Medical Genetics, Changde First People's Hospital, Changde, China
| | - Dan Peng
- Department of Medical Genetics, Changde First People's Hospital, Changde, China.,Affiliated Hospital of Changde City, University of South China, Hengyang, China
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Perrault JR, Lasala JA, Manire CA, Coppenrath CM, Page-Karjian A, Blew A, Stacy NI. NONPIGMENTED VERSUS PIGMENTED: HEALTH VARIABLES AND GENETICS OF ALBINO FLORIDA GREEN TURTLE (CHELONIA MYDAS) HATCHLINGS COMPARED WITH NORMALLY PIGMENTED HATCHLINGS FROM THE SAME CLUTCH. J Wildl Dis 2021. [PMID: 34699596 DOI: 10.7589/JWD-D-21-00031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/15/2021] [Indexed: 11/20/2022]
Abstract
At the time of hatchling emergence from a nest laid on Juno Beach, Florida, USA, by a normally pigmented green turtle (Chelonia mydas), 23 albino hatchlings and 75 normally pigmented hatchlings were observed. This condition is rarely seen in sea turtles, and little is known about blood analytes and genetics of albino wildlife to date. Therefore, the objective of our study was to assess and compare morphometric measurements (mass, minimum straight carapace length, body condition index), carapacial scute anomalies, a suite of hematologic and plasma biochemical analytes, and two glucose analysis methodologies (glucometer and dry chemistry analysis) in albino (n=20) versus normally pigmented (n=24) hatchlings from this nest. Genetic analyses were completed to identify paternal contributions of hatchlings and to test Mendelian inheritance assumptions. Although morphometric measurements, scute anomalies, and leukocyte morphology were similar between albino and normally pigmented hatchlings, several differences were observed in blood analyte data: immature erythrocytes, packed cell volume, heterophil:lymphocyte ratio, and glucose concentrations (by both methodologies) were significantly higher, whereas absolute immature heterophils, absolute lymphocytes, number of erythrocyte micronuclei, sodium, and chloride were significantly lower in albino hatchlings compared with normally pigmented hatchlings. Considerations for these differences include a stress response from sampling (e.g., timing of procedures or possibly from photosensitivity or reduced visual acuity in albinos) and different osmoregulation, which may reflect physiologic variations or stress. There was a small positive bias (0.10 mmol/L) with glucose by glucometer, similar to reports in other sea turtle species and confirming its suitability for use in hatchlings. All albino hatchlings analyzed (n=10) were from the same father, but the normally pigmented hatchlings (n=24) were from two other fathers. These findings provide insight into the physiology and genetics of albinism in sea turtles.
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Abstract
OBJECTIVE To compare the vessel geometry characteristics of color fundus photographs in normal control and diabetes mellitus (DM) patients and to find potential biomarkers for early diabetic retinopathy (DR) based on a neural network vessel segmentation system and automated vascular geometry parameter analysis software. METHODS A total of 102 consecutive patients with type 2 DM (T2DM) and 132 healthy controls were recruited. All participants underwent general ophthalmic examinations, and retinal fundus photographs were taken with a digital fundus camera without mydriasis. Color fundus photographs were input into a dense-block generative adversarial network (D-GAN)-assisted retinal vascular segmentation system (http://www.gdcerc.cn:8081/#/login) to obtain binary images. These images were then analyzed by customized software (ocular microvascular analysis system V2.9.1) for automatic processing of vessel geometry parameters, including the monofractal dimension (Dbox), multifractal dimension (D0), vessel area ratio (R), max vessel diameter (dmax), average vessel diameter (dave), arc-chord ratio (A/C), and tortuosity (τn). Geometric differences between the healthy subjects and DM patients were analyzed. Then, regression analysis and receiver operating characteristic (ROC) curve analysis were performed to evaluate the diagnostic efficiency of the vascular geometry parameters. RESULTS No significant differences were observed between the baseline characteristics of each group. DM patients had lower Dbox and D0 values (1.330 ± 0.041; 1.347 ± 0.038) than healthy subjects (1.343 ± 0.048, p < 0.05; 1.362 ± 0.042, p < 0.05) and showed increasing values of dmax, dave, A/C, and τn compared with normal controls, although only the differences in dave and τn between the groups were statistically significant. In the regression analysis, dave and τn showed a good correlation with diabetes (dave, OR 1.765, 95% CI 1.319-2.362, p < 0.001; τn, OR 9.323, 95% CI 1.492-58.262, p < 0.05). CONCLUSIONS We demonstrated the relationship between retinal vascular geometry and the process in DM patients, showing that Dbox, D0, dave, and τn may be indicators of morphological changes in retinal vessels in DM patients and can be early biomarkers of DR.
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Affiliation(s)
- Meng Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Gengyuan Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Honghui Xia
- Department of Ophthalmology, Zhaoqing Gaoyao People's Hospital, Zhaoqing, People's Republic of China
| | - Ziqing Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Peng Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Ramos AN, Ramos JGR, Fernandes JD. Prevalence of premalignant and malignant skin lesions in oculocutaneous albinism patients. ACTA ACUST UNITED AC 2021; 67:77-82. [PMID: 34161467 DOI: 10.1590/1806-9282.67.01.20200356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 08/30/2020] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Oculocutaneous albinism describes a group of pigmentary disorders that lead to skin sensitivity and predisposition to skin malignances. AIMS To analyze clinical and epidemiological data in oculocutaneous albinism patients and to determine the prevalence of malignant skin lesions, assessing possible risk factors for skin cancer. METHODS Cross-sectional study evaluating epidemiological data, habits of sun exposure and sun protection, and clinical examination of albino patients followed in a reference dermatology outpatient clinic in Brasil. Our primary outcome was the occurrence of malignant skin lesions in biopsied tissues. RESULTS Of 74 patients analyzed, 11 (15%) had one or more suspicious lesions and were biopsied, of which 8 (72.7%) patients presented with basal cell carcinomas, 7 (63.3%) presented with squamous cell carcinoma, and 1 (9%) presented with melanoma. Moreover, 32(43%) patients presented with actinic keratosis. Age, female gender, previous history of sunburn, history of malignant lesions and history of sun exposure without photoprotection were associated with the presence of malignant lesions. LIMITATIONS Unicentric, non-aleatory sample. CONCLUSIONS There was a high prevalence of malignant and pre-malignant lesions in this population. Some potentially modifiable risk factors were associated with the occurrence of malignant skin lesions.
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Affiliation(s)
- Andréia Nogueira Ramos
- Universidade Federal da Bahia, Programa de Pós-graduação em Ciências da Saúde - Salvador (BA), Brasil
| | | | - Juliana Dumet Fernandes
- Hospital Universitário Professor Edgard Santos, Departamento de Dermatologia - Salvador (BA), Brasil
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11
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Kruijt CC, Schalij-Delfos NE, de Wit GC, Florijn RJ, van Genderen MM. Evident hypopigmentation without other ocular deficits in Dutch patients with oculocutaneous albinism type 4. Sci Rep 2021; 11:11572. [PMID: 34078970 DOI: 10.1038/s41598-021-90896-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
To describe the phenotype of Dutch patients with oculocutaneous albinism type 4 (OCA4), we collected data on pigmentation (skin, hair, and eyes), visual acuity (VA), nystagmus, foveal hypoplasia, chiasmal misrouting, and molecular analyses of nine Dutch OCA4 patients from the Bartiméus Diagnostic Center for complex visual disorders. All patients had severely reduced pigmentation of skin, hair, and eyes with iris transillumination over 360 degrees. Three unrelated OCA4 patients had normal VA, no nystagmus, no foveal hypoplasia, and no misrouting of the visual pathways. Six patients had poor visual acuity (0.6 to 1.0 logMAR), nystagmus, severe foveal hypoplasia and misrouting. We found two novel variants in the SLC45A2 gene, c.310C > T; (p.Pro104Ser), and c.1368 + 3_1368 + 9del; (p.?). OCA4 patients of this Dutch cohort all had hypopigmentation of skin, hair, and iris translucency. However, patients were either severely affected with regard to visual acuity, foveal hypoplasia, and misrouting, or visually not affected at all. We describe for the first time OCA4 patients with an evident lack of pigmentation, but normal visual acuity, normal foveal development and absence of misrouting. This implies that absence of melanin does not invariably lead to foveal hypoplasia and abnormal routing of the visual pathways.
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12
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Moreno-Artero E, Morice-Picard F, Bremond-Gignac D, Drumare-Bouvet I, Duncombe-Poulet C, Leclerc-Mercier S, Dufresne H, Kaplan J, Jouanne B, Arveiler B, Taieb A, Hadj-Rabia S. Management of albinism: French guidelines for diagnosis and care. J Eur Acad Dermatol Venereol 2021; 35:1449-1459. [PMID: 34042219 DOI: 10.1111/jdv.17275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 03/22/2021] [Indexed: 12/12/2022]
Abstract
Albinism is a worldwide genetic disorder caused by mutations in at least 20 genes, identified to date, that affect melanin production or transport in the skin, hair and eyes. Patients present with variable degrees of diffuse muco-cutaneous and adnexal hypopigmentation, as well as ocular features including nystagmus, misrouting of optic nerves and foveal hypoplasia. Less often, albinism is associated with blood, immunological, pulmonary, digestive and/or neurological anomalies. Clinical and molecular characterizations are essential in preventing potential complications. Disease-causing mutations remain unknown for about 25% of patients with albinism. These guidelines have been developed for the diagnosis and management of syndromic and non-syndromic forms of albinism, based on a systematic review of the scientific literature. These guidelines comprise clinical and molecular characterization, diagnosis, therapeutic approach and management.
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Affiliation(s)
- E Moreno-Artero
- Department of Dermatology, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Hôpital Universitaire Necker- Enfants Malades, Assistance Publique - Hôpitaux de Paris-Centre (AP-HP5), Paris, France
| | - F Morice-Picard
- Pediatric Dermatology Unit, National Centre for Rare Skin Disorders, Hôpital Pellegrin-Enfants, CHU de Bordeaux, Bordeaux, France
| | - D Bremond-Gignac
- Department of Ophthalmology, Reference Centre for Rare Ocular Diseases (OPHTARA), Hôpital Necker-Enfants Malades, APHP5, Paris, France.,Université de Paris-Centre, Paris, France
| | - I Drumare-Bouvet
- Service d'exploration de la vision et neuro-ophtalmologie, CHRU de Lille, Lille, France
| | | | - S Leclerc-Mercier
- Department of Pathology, Hôpital Necker-Enfants Malades, APHP5, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Université de Paris-Centre, Paris, France
| | - H Dufresne
- Department of Dermatology, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Hôpital Universitaire Necker- Enfants Malades, Assistance Publique - Hôpitaux de Paris-Centre (AP-HP5), Paris, France.,Service Social Pédiatrique, Hôpital Necker-Enfants Malades, APHP5, Université de Paris-Centre, Paris, France
| | - J Kaplan
- Laboratory of Genetics in Ophthalmology, Imagine Institute, Paris, France
| | - B Jouanne
- French Association for Albinism (Genespoir), Rennes, France
| | - B Arveiler
- Molecular Genetics Laboratory, CHU de Bordeaux, Bordeaux, France.,INSERM U1211, Maladies Rares, Génétique et Métabolisme, Bordeaux, France
| | - A Taieb
- Pediatric Dermatology Unit, National Centre for Rare Skin Disorders, Hôpital Pellegrin-Enfants, CHU de Bordeaux, Bordeaux, France
| | - S Hadj-Rabia
- Department of Dermatology, Reference Center for Genodermatoses and Rare Skin Diseases (MAGEC), Hôpital Universitaire Necker- Enfants Malades, Assistance Publique - Hôpitaux de Paris-Centre (AP-HP5), Paris, France.,Université de Paris-Centre, Paris, France
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13
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Abstract
BACKGROUND The study aimed to describe genotype-phenotype associations in patients with oculocutaneous and ocular-only albinism and to evaluate a set of diagnostic criteria proposed recently by Kruijt et al. MATERIALS AND METHODS Genotype-phenotype associations in patients with a clinical diagnosis of albinism were studied based on imaging of hair and ocular features (nystagmus, iris color and translucency, fundus pigmentation and foveal development) and self-evaluated skin type. Patients were sub-grouped based on genetic findings. RESULTS Patients with biallelic variants in TYR (n = 29), OCA2 (n = 22), other albinism genes (n = 13) or monoallelic variants in GPR143 (n = 13) were included as were 15 patients with a pure clinical diagnosis but no genetic findings. In descending order the most common findings were: foveal hypoplasia (any hypoplasia 95.2%, severe 88.0%), nystagmus (93.5%), iris translucency (any translucency 80.2%, moderate to severe 31.5%), misrouting on VEP (80.0%): fundus hypopigmentation (any hypopigmentation: 75.8%, severe 30.1%), fair skin type (73.8%), blue irides (62.0%), blonde hair (57.5%), and unpigmented eye lashes (39.1%). There were no phenotypic differences between the different genetic subgroups of albinism but patients with a pathogenic haplotype in TYR in combination with a classic variant had less iris translucency than patients with two classic variants in TYR. CONCLUSIONS Ocular developmental features were the most common findings whereas phenotypic features related to pigmentation were less common findings but there were no genotype-phenotype correlations. All patients with a genetically confirmed diagnosis of albinism fulfilled the diagnostic criteria by Kruijt irrespective of genetic subtype.
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Affiliation(s)
- Line Kessel
- Department of Ophthalmology, Rigshospitalet-Kennedy Center, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen Denmark
| | - Birgit Kjer
- Department of Ophthalmology, Rigshospitalet-Kennedy Center, Denmark
| | - Ulrikke Lei
- Department of Clinical Medicine, University of Copenhagen, Copenhagen Denmark.,Department of Dermatology and Allergy, Herlev and Gentofte Hospital, Denmark
| | - Morten Duno
- Department of Clinical Genetics, Rigshospitalet-Kennedy Center, Denmark
| | - Karen Grønskov
- Department of Clinical Genetics, Rigshospitalet-Kennedy Center, Denmark
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Abstract
Purpose: Oculocutaneous albinism type 1A (OCA1A), with lifelong absent melanin in skin, hair, and eyes, is the most severe type of albinism with greatest ametropia and poorest vision. We evaluated the relationship between age when spectacles were begun and visual outcome, in addition to status of refraction, in OCA1A. Methods: After IRB approval, a retrospective review of 70 consecutive charts of patients with OCA1A identified 24 fitting inclusion criterion of BCVA recorded at age 10-12 years. Exclusion criteria were those with other vision-threatening diagnoses and patients seen for a single visit. We recorded sex, age at beginning glasses, and refraction and BCVA at age 10-12 and most recent visit. Data were arbitrarily grouped by those initiating glasses at ≤ age 12 months and > age 12 months. Results: Regression analysis showed a larger degree of astigmatism was weakly associated with worse vision at age 10-12 years. A weakly positive relationship was found between poorer BCVA at last visit and older age at which glasses were initiated. All receiving glasses by age 1 and only half receiving glasses when older had improved visual acuity from age 10-12 years to last follow up. Conclusion: Additional study of a larger sample of this rare disorder is needed to determine if early glasses wear improves later BCVA.
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Affiliation(s)
- Laura May
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota , Minneapolis, Minnesota
| | - Kimberly Merrill
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota , Minneapolis, Minnesota
| | - John E Connett
- School of Public Health, Division of Biostatistics, University of Minnesota , Minneapolis, Minnesota
| | - C Gail Summers
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota , Minneapolis, Minnesota.,Department of Pediatrics, University of Minnesota , Minneapolis, Minnesota
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15
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Chuan Z, Yan Y, Hao S, Zhang Q, Zhou B, Feng X, Wang X, Liu F, Zheng L, Cao Z, Ma X. Mutation Analysis of 63 Northwest Chinese Probands with Oculocutaneous Albinism. Curr Eye Res 2020; 46:140-143. [PMID: 32552135 DOI: 10.1080/02713683.2020.1781192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To identify the mutational spectrum of 63 northwest Chinese probands with Oculocutaneous albinism (OCA), and identify correlations between phenotype and genotype. METHODS We recruited 63 clinically diagnosed with OCA patients in Gansu Provincial Maternal and Child Health Care Hospital. Mutation screening analysis was performed by direct sequencing and NGS-target sequencing to screen the variants on genes related to OCA. PolyPhen2 and PROVEN tools were used to predict the possible functional role of the novel variants. We assessed the pathogenicity of the novel mutations according to the clinical interpretation of genetic variants by ACMG/AMP 2015 guideline. RESULTS By molecular testing, 56 of the OCA probands were diagnosed as OCA 1, three were OCA 2 and one was OCA 4. The most common variants of TYR were c.929insC(33.7%), c.896 G > A(12.5%), c.832 C > T(9.6%).We found five novel variants of TYR that have not previously been reported. CONCLUSIONS We make an accurate diagnosis and classification for the OCA probands. Our result enlarged the mutational spectrum of TYR and SLC45A2. These findings could be useful for genetic counseling and gene diagnosis of OCA in Northwest of China.
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Affiliation(s)
- Zhang Chuan
- Graduate School of Peking Union Medical College , Beijing, China.,National Research Institute for Family Planning , Beijing, China.,Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Yousheng Yan
- National Research Institute for Family Planning , Beijing, China
| | - Shengju Hao
- Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Qinghua Zhang
- Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Bingbo Zhou
- Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Xuan Feng
- Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Xing Wang
- Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Furong Liu
- Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Lei Zheng
- Gansu Province Medical Genetics Center, Gansu Province Maternal and Child Health Care Hospital , Lanzhou, China
| | - Zongfu Cao
- Graduate School of Peking Union Medical College , Beijing, China.,National Research Institute for Family Planning , Beijing, China.,National Human Genetic Resources Center , Beijing, China
| | - Xu Ma
- Graduate School of Peking Union Medical College , Beijing, China.,National Research Institute for Family Planning , Beijing, China.,National Human Genetic Resources Center , Beijing, China
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16
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kruijt CC, de Wit GC, Bergen AA, Florijn RJ, Schalij-Delfos NE, van Genderen MM. The Phenotypic Spectrum of Albinism. Ophthalmology 2018; 125:1953-1960. [DOI: 10.1016/j.ophtha.2018.08.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 11/28/2022] Open
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Wang Y, Zhou YF, Shen N, Zhu YW, Tan K, Wang X. Identification of a Homozygous Missense Mutation in the TYR Gene in a Chinese Family with OCA1. Curr Med Sci 2018; 38:932-936. [PMID: 30341532 DOI: 10.1007/s11596-018-1965-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/20/2018] [Indexed: 12/28/2022]
Abstract
Oculocutaneous albinism (OCA) is an autosomal recessive pigmentation abnormality, characterized by variable hair, skin, and ocular hypopigmentation. OCA1 is the most frequent subtype of OCA, caused by mutations in the tyrosinase gene (TYR). In this study, we investigated the genetic mutation of a Chinese family with a female OCA patient who came for genetic counseling before pregnancy. Complete physical examination was performed, and DNA from blood samples was collected from the family members. Mutations of TYR, OCA2, and SLC45A2 genes were examined in the proband, and verified in her parents by Sanger sequencing. Large deletion or duplication of TYR and OCA2 genes was detected by multiplex ligation-dependent probe amplification (MLPA). A homozygous TYR c.307T>C (p.Cys103Arg) missense mutation was identified in the proband, and both parents were heterozygous carriers. No large deletion or duplication was found in the proband. This mutation was absent in 1000G, ExAC, or HGMD database, and multiple lines of in silico tools supported a deleterious effect. These results suggest that TYR c.307T>C mutation might be responsible for OCA1, and our study further expands the mutation spectrum of OCA1 in the Chinese population.
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Affiliation(s)
- Yan Wang
- Department of Neurosurgery, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yi-Fan Zhou
- Reproductive Medicine Center, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Na Shen
- Department of Laboratory Medicine, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yao-Wu Zhu
- Department of Laboratory Medicine, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Kun Tan
- Department of Infection Control, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Xiong Wang
- Department of Laboratory Medicine, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Morice-Picard F, Taïeb C, Marti A, Gliksohn A, Bennani M, Bodemer C, Ezzedine K. Burden of albinism: development and validation of a burden assessment tool. Orphanet J Rare Dis 2018; 13:162. [PMID: 30227882 PMCID: PMC6145119 DOI: 10.1186/s13023-018-0894-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 08/20/2018] [Indexed: 11/22/2022] Open
Abstract
Background Albinism comprises a group of autosomal recessive diseases that are characterized by poor vision and a variable hypopigmentation phenotype. A comprehensive literature review showed that no tool can assess the burden experienced by individuals who present with albinism, although such a tool is needed and would be beneficial for clinicians and patients alike. Method The questionnaire was devised using standardized methodology for developing and validating questionnaires on the quality of life of subjects according to the following chronological structure: conceptual phase, development phase, and then validation phase. A multidisciplinary working group was assembled, including experts on questionnaire design and development, dermatologists specializing in care for patients with albinism, and representatives of the Genespoir association. Results Based on an initial verbatim report, the workgroup compiled a list of items that were transcribed and reformulated into questions. During the validation phase, principal component analysis (PCA) was conducted on the 24 items, which allowed the questionnaire to be reduced to 20 questions [Q]. The standardized regression coefficients were all greater than 0.5 for their corresponding factors. Based on their normalized regression coefficients, each group of questions was linked to one of the following four dimensions, with each dimension consisting of at least three questions: “Live with” (8 Q), “Daily life” (3 Q), “Resignation” (3 Q), and “Fear of the future” (6 Q). All dimensions correlated well with the overall BoA score. Cronbach’s α was 0.92 for the entire BoA scale, confirming excellent internal coherence. Intradimensional coherences all demonstrated excellent reliability (α > 0.65). The BoA questionnaire was highly correlated with the SF12, RSES and DLQI validated questionnaires. This outcome confirmed the external validity. Conclusion This questionnaire represents the first specific assessment tool for evaluating the burden of albinism. It is easy to use and relatively quick to complete, which will allow the burden to be evaluated over time with a reproducible questionnaire. To ensure that this questionnaire can be used by as many people as possible, cultural and linguistic validation in US English was conducted with the original French version. Electronic supplementary material The online version of this article (10.1186/s13023-018-0894-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Charles Taïeb
- FIMARAD, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | | | | | | | - Christine Bodemer
- MAGEC, CHU Necker-Enfants Malades, APHP, Paris, France.,Annimatrice, FIMARAD, Hôpital Necker-Enfants Malades, APHP, Paris, France
| | - Khaled Ezzedine
- EA EpiDermE, UPE-Université Paris-Est, Créteil, France.,CHU H Mondor, APHP, Créteil, France
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21
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Wang X, Zhu Y, Shen N, Peng J, Wang C, Liu H, Lu Y. Mutation analysis of a Chinese family with oculocutaneous albinism. Oncotarget 2018; 7:84981-84988. [PMID: 27829221 PMCID: PMC5356713 DOI: 10.18632/oncotarget.13109] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/22/2016] [Indexed: 11/25/2022] Open
Abstract
Oculocutaneous albinism (OCA) is an autosomal recessive disorder characterized by either complete lack of or a reduction in melanin biosynthesis in the skin, hair, and eyes. OCA1, the most common and severe type, is caused by mutations in the tyrosinase (TYR) gene. In this study, we report a Chinese family with two members affected by OCA. Blood samples were collected from all family members. Genomic DNA was isolated from blood leukocytes, and all coding exons and adjacent intronic sequences of the TYR gene were examined for mutation analysis using polymerase chain reaction (PCR)-based sequencing. A pedigree chart was drawn, and clinical examinations and paraclinical tests were performed. Compound heterozygous mutations in TYR (c.832C>T and c.929_930insC, which resulted in p.Arg278* and p.Arg311Lysfs*7, respectively) were identified in the two patients with milky skin, white hair, photophobia, and reduced visual acuity, while other family members only carried one of two heterozygous mutations. In addition, a homozygous missense mutation c.814G>A (p.Glu272Lys) in the solute carrier family 45 member 2 (SLC45A2) gene was found in both patients and unaffected family members, suggesting that this may not be a causative mutation. The findings of this study expand the mutational spectrum of OCA. Compound heterozygous mutations (c.832C>T and c.929_930insC) in the TYR gene may be responsible for partial clinical manifestations of OCA, while the homozygous missense mutation c.814G>A (p.Glu272Lys) in the SLC45A2 gene may not be associated with OCA.
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Affiliation(s)
- Xiong Wang
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yaowu Zhu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Na Shen
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jing Peng
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chunyu Wang
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Haiyi Liu
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yanjun Lu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Norman CS, O'Gorman L, Gibson J, Pengelly RJ, Baralle D, Ratnayaka JA, Griffiths H, Rose-Zerilli M, Ranger M, Bunyan D, Lee H, Page R, Newall T, Shawkat F, Mattocks C, Ward D, Ennis S, Self JE. 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 DOI: 10.1038/s41598-017-04401-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Lu Q, Yuan L, Xu H, Huang X, Yang Z, Yi J, Ni B, Chen Y, Deng H. Identification of a missense mutation in the tyrosinase gene in a Chinese family with oculocutaneous albinism type 1. Mol Med Rep 2017; 15:1426-1430. [PMID: 28112372 DOI: 10.3892/mmr.2017.6137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 12/07/2016] [Indexed: 11/05/2022] Open
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Mauri L, Manfredini E, Del Longo A, Veniani E, Scarcello M, Terrana R, Radaelli AE, Calò D, Mingoia G, Rossetti A, Marsico G, Mazza M, Gesu GP, Cristina Patrosso M, Penco S, Piozzi E, Primignani P. Clinical evaluation and molecular screening of a large consecutive series of albino patients. J Hum Genet 2017; 62:277-90. [PMID: 27734839 DOI: 10.1038/jhg.2016.123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Winsor CN, Holleschau AM, Connett JE, Summers CG. A cross-sectional examination of visual acuity by specific type of albinism. J AAPOS 2016; 20:419-24. [PMID: 27647118 DOI: 10.1016/j.jaapos.2016.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 06/07/2016] [Accepted: 06/10/2016] [Indexed: 11/22/2022]
Abstract
PURPOSE Reports of best-corrected visual acuity (BCVA) in albinism are often based on overlapping clinical phenotypes. BCVA in albinism has been shown to improve with age. This study reports a large cross-sectional investigation to determine whether BCVA differs by specific type of albinism when age-corrected. METHODS This retrospective review identified 170 individuals with a specific type of albinism identified by mutation(s) in a gene known to cause albinism (for OCA1, OCA2, and Hermansky-Pudlak syndrome ([HPS]) or a specific phenotype (white hair and no melanin pigment in OCA1A; pigmentary mosaicism in the obligate carriers for males with OA1). We recorded optotype binocular BCVA at final follow-up. Patients were age-grouped (2-5 years, 6-14 years, and ≥15 years) for comparison. RESULTS The greatest visual acuity deficit was found for OCA1A in all age groups. At age ≥15 years (n = 79), mean BCVA was 20/128 for OCA1A, 20/37 for OCA1B, 20/59 for OCA2, 20/63 for OA1, and 20/121 for HPS. Significant differences between BCVA at ≥15 years were found in the following: OCA1A vs OCA1B, OCA1A vs OCA2, OCA1A vs OA1, OCA1B vs HPS, OCA2 vs HPS, and OA1 vs HPS (P ≤ 0.02). CONCLUSIONS This study provides a large sample size and includes only those with a specific type of albinism. BCVA varies by albinism type, and there is overlap in BCVA, particularly in the younger age groups. For ages ≥15 years, there are significant differences in BCVA between several types of albinism.
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Kamaraj B, Purohit R. Mutational Analysis on Membrane Associated Transporter Protein (MATP) and Their Structural Consequences in Oculocutaeous Albinism Type 4 (OCA4)-A Molecular Dynamics Approach. J Cell Biochem 2016; 117:2608-19. [PMID: 27019209 DOI: 10.1002/jcb.25555] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/24/2016] [Indexed: 12/11/2022]
Abstract
Oculocutaneous albinism type IV (OCA4) is an autosomal recessive inherited disorder which is characterized by reduced biosynthesis of melanin pigmentation in skin, hair, and eyes and caused by the genetic mutations in the membrane-associated transporter protein (MATP) encoded by SLC45A2 gene. The MATP protein consists of 530 amino acids which contains 12 putative transmembrane domains and plays an important role in pigmentation and probably functions as a membrane transporter in melanosomes. We scrutinized the most OCA4 disease-associated mutation and their structural consequences on SLC45A2 gene. To understand the atomic arrangement in 3D space, the native and mutant structures were modeled. Further the structural behavior of native and mutant MATP protein was investigated by molecular dynamics simulation (MDS) approach in explicit lipid and water background. We found Y317C as the most deleterious and disease-associated SNP on SLC45A2 gene. In MDS, mutations in MATP protein showed loss of stability and became more flexible, which alter its structural conformation and function. This phenomenon has indicated a significant role in inducing OCA4. Our study explored the understanding of molecular mechanism of MATP protein upon mutation at atomic level and further helps in the field of pharmacogenomics to develop a personalized medicine for OCA4 disorder. J. Cell. Biochem. 117: 2608-2619, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Balu Kamaraj
- Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk-Antwerp, Belgium
| | - Rituraj Purohit
- Department of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India.
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Wolfson Y, Fletcher E, Strauss RW, Scholl HP. Evidence of macular pigment in the central macula in albinism. Exp Eye Res 2016; 145:468-71. [DOI: 10.1016/j.exer.2015.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/30/2015] [Accepted: 10/05/2015] [Indexed: 11/21/2022]
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Hanovice NJ, Daly CMS, Gross JM. N-Ethylmaleimide-Sensitive Factor b (nsfb) Is Required for Normal Pigmentation of the Zebrafish Retinal Pigment Epithelium. Invest Ophthalmol Vis Sci 2016; 56:7535-44. [PMID: 26618645 DOI: 10.1167/iovs.15-17704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Despite the number of albinism-causing mutations identified in human patients and animal models, there remain a significant number of cases for which no mutation has been identified, suggesting that our understanding of melanogenesis is incomplete. Previously, we identified two oculocutaneous albinism mutations in zebrafish, au13 and au18. Here, we sought to identify the mutated loci and determine how the affected proteins contribute to normal pigmentation of the retinal pigment epithelium (RPE). METHODS Complementation analyses revealed that au13 and au18 belonged to a single complementation group, suggesting that they affected the same locus. Whole-genome sequencing and single nucleotide polymorphism (SNP) analysis was performed to identify putative mutations, which were confirmed by cDNA sequencing and mRNA rescue. Transmission electron microscopy (TEM) and image quantification were used to identify the cellular basis of hypopigmentation. RESULTS Whole-genome sequencing and SNP mapping identified a nonsense mutation in the N-ethylmaleimide-sensitive factor b (nsfb) gene in au18 mutants. Complementary DNA sequencing confirmed the presence of the mutation (C893T), which truncates the nsfb protein by roughly two-thirds (Y297X). No coding sequence mutations were identified in au13, but quantitative PCR revealed a significant decrease in nsfb expression, and nsfb mRNA injection rescued the hypopigmentation phenotype, suggesting a regulatory mutation. In situ hybridization revealed that nsfb is broadly expressed during embryonic development, including in the RPE. Transmission electron microscopy analyses indicated that average melanosome density and maturity were significantly decreased in nsfb mutants. CONCLUSIONS au18 and au13 contain mutations in nsfb, which encodes a protein that is required for the maturation of melanosomes in zebrafish RPE.
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Khordadpoor-Deilamani F, Akbari MT, Karimipoor M, Javadi GR. Homozygosity mapping in albinism patients using a novel panel of 13 STR markers inside the nonsyndromic OCA genes: introducing 5 novel mutations. J Hum Genet 2016; 61:373-9. [DOI: 10.1038/jhg.2015.167] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/16/2015] [Accepted: 11/26/2015] [Indexed: 02/06/2023]
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Hull S, Arno G, Holder GE, Plagnol V, Gomez K, Liesner R, Webster AR, Moore AT. The ophthalmic presentation of Hermansky-Pudlak syndrome 6. Br J Ophthalmol 2016; 100:1521-1524. [PMID: 26823395 DOI: 10.1136/bjophthalmol-2015-308067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/02/2016] [Indexed: 11/03/2022]
Abstract
BACKGROUND Hermansky-Pudlak syndrome (HPS) may present to the ophthalmologist with signs suggestive of oculocutaneous albinism. Consideration of HPS as a differential diagnosis is important due to its potential systemic complications. HPS6 is a rarely reported subtype. METHODS Three patients from two families underwent clinical examination, imaging and targeted systemic investigations. Electrophysiology with visual-evoked potentials (VEPs) was performed in both children of family 1. Whole exome sequencing (WES) was performed on the proband of family 1. Bidirectional Sanger sequencing of the single exon and intron-exon boundaries of HPS6 was performed on all affected patients and segregation confirmed in available relatives. RESULTS Two siblings presented in infancy with nystagmus and reduced vision. They were initially diagnosed with isolated foveal hypoplasia with no aberrant chiasmal misrouting on VEPs. WES performed in the proband when 10 years of age identified a novel homozygous missense variant in HPS6 and further questioning elicited a history of nose bleeds and mild bruising. Segregation supported causality of this variant in the affected younger sibling. In the third unrelated patient, an initial diagnosis of ocular albinism was made at 3 months with HPS only diagnosed at 26 years. Biallelic, truncating mutations in HPS6 were identified by candidate Sanger sequencing and included a novel variant. Abnormal platelet function consistent with HPS was confirmed in all patients. CONCLUSIONS The diagnosis of HPS in all patients was delayed due to a mild systemic phenotype. Next-generation sequencing can aid diagnosis of syndromic conditions with important consequences for preventing morbidity.
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Affiliation(s)
- Sarah Hull
- University College London Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
| | - Gavin Arno
- University College London Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
| | - Graham E Holder
- University College London Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
| | | | - Keith Gomez
- Haematology Department, Royal Free London NHS Foundation Trust, London, UK
| | - Ri Liesner
- Haematology Department, Great Ormond Street Hospital for Children NHS Trust, London, UK
- Haematology Department, University College London Hospitals, London, UK
| | - Andrew R Webster
- University College London Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
| | - Anthony T Moore
- University College London Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
- San Francisco Medical Centre, University of California, San Francisco, California, USA
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Khordadpoor-Deilamani F, Akbari MT, Karimipoor M, Javadi G. Sequence analysis of tyrosinase gene in ocular and oculocutaneous albinism patients: introducing three novel mutations. Mol Vis 2015; 21:730-5. [PMID: 26167114 PMCID: PMC4499471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/08/2015] [Indexed: 10/29/2022] Open
Abstract
PURPOSE Albinism is a heterogeneous genetic disorder of melanin synthesis that results in hypopigmented eyes (in patients with ocular albinism) or hair, skin, and eyes (in individuals with oculocutaneous albinism). It is associated with decreased visual acuity, nystagmus, strabismus, and photophobia. The tyrosinase gene is known to be involved in both oculocutaneous albinism and autosomal recessive ocular albinism. In this study, we aimed to screen the mutations in the TYR gene in the nonsyndromic OCA and autosomal recessive ocular albinism patients from Iran. METHODS The tyrosinase gene was examined in 23 unrelated patients with autosomal recessive ocular albinism or nonsyndromic OCA using DNA sequencing and bioinformatics analysis. RESULTS TYR gene mutations were identified in 14 (app. 60%) albinism patients. CONCLUSIONS We found 10 mutations, 3 of which were novel. No mutation was found in our ocular albinism patients, but one of them was heterozygous for the p.R402Q polymorphism.
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Affiliation(s)
| | - Mohammad Taghi Akbari
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran,Tehran Medical Genetics Laboratory, Tehran, Iran
| | - Morteza Karimipoor
- Tehran Medical Genetics Laboratory, Tehran, Iran,Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Gholamreza Javadi
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
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Straniero L, Rimoldi V, Soldà G, Mauri L, Manfredini E, Andreucci E, Bargiacchi S, Penco S, Gesu GP, Del Longo A, Piozzi E, Asselta R, Primignani P. Two novel splicing mutations in the SLC45A2 gene cause Oculocutaneous Albinism Type IV by unmasking cryptic splice sites. J Hum Genet 2015; 60:467-71. [PMID: 26016411 DOI: 10.1038/jhg.2015.56] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/30/2015] [Accepted: 04/26/2015] [Indexed: 11/08/2022]
Abstract
Oculocutaneous albinism (OCA) is characterized by hypopigmentation of the skin, hair and eye, and by ophthalmologic abnormalities caused by a deficiency in melanin biosynthesis. OCA type IV (OCA4) is one of the four commonly recognized forms of albinism, and is determined by mutation in the SLC45A2 gene. Here, we investigated the genetic basis of OCA4 in an Italian child. The mutational screening of the SLC45A2 gene identified two novel potentially pathogenic splicing mutations: a synonymous transition (c.888G>A) involving the last nucleotide of exon 3 and a single-nucleotide insertion (c.1156+2dupT) within the consensus sequence of the donor splice site of intron 5. As computer-assisted analysis for mutant splice-site prediction was not conclusive, we investigated the effects on pre-mRNA splicing of these two variants by using an in vitro minigene approach. Production of mutant transcripts in HeLa cells demonstrated that both mutations cause the almost complete abolishment of the physiologic donor splice site, with the concomitant unmasking of cryptic donor splice sites. To our knowledge, this work represents the first in-depth molecular characterization of splicing defects in a OCA4 patient.
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McCafferty BK, Wilk MA, McAllister JT, Stepien KE, Dubis AM, Brilliant MH, Anderson JL, Carroll J, Summers CG. Clinical Insights Into Foveal Morphology in Albinism. J Pediatr Ophthalmol Strabismus 2015; 52:167-72. [PMID: 26053207 PMCID: PMC4948980 DOI: 10.3928/01913913-20150427-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 01/13/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE A hallmark of albinism is foveal hypoplasia. However, literature suggests variable foveal development. This study evaluates the association between ocular phenotype and foveal morphology to demonstrate the broad structural and functional spectrum. METHODS Best-corrected visual acuity (BCVA), nystagmus, angle kappa, stereoacuity, iris transillumination, macular melanin presence, foveal avascular zone, and annular reflex were recorded in 14 patients with albinism. Spectral-domain optical coherence tomography provided macular images. RESULTS The clinical phenotype was broad, with BCVA varying from 20/20 to 20/100. Better BCVA was associated with a preserved foveal avascular zone, annular macular reflex, stereoacuity, and macular melanin. Imaging demonstrated a continuum of foveal development correlating with BCVA. Individuals with a rudimentary pit had normal inner and outer segment lengthening and better BCVA. CONCLUSIONS The spectrum of ocular structure and visual function in albinism is broad, suggesting a possible diagnosis of albinism in a patient with an even more normal clinical presentation.
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MESH Headings
- Adolescent
- Adult
- Aged, 80 and over
- Albinism, Ocular/diagnosis
- Albinism, Ocular/genetics
- Albinism, Ocular/physiopathology
- Albinism, Oculocutaneous/diagnosis
- Albinism, Oculocutaneous/genetics
- Albinism, Oculocutaneous/physiopathology
- Child
- DNA Mutational Analysis
- Depth Perception/physiology
- Evoked Potentials, Visual
- Eye Abnormalities/diagnosis
- Eye Abnormalities/genetics
- Eye Abnormalities/physiopathology
- Eye Proteins/genetics
- Female
- Fovea Centralis/abnormalities
- Fovea Centralis/pathology
- Humans
- Male
- Membrane Proteins/genetics
- Nystagmus, Pathologic/diagnosis
- Phenotype
- Polymerase Chain Reaction
- Prospective Studies
- Tomography, Optical Coherence
- Visual Acuity/physiology
- Young Adult
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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: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Kamaraj B, Purohit R. Mutational analysis of oculocutaneous albinism: a compact review. Biomed Res Int 2014; 2014:905472. [PMID: 25093188 DOI: 10.1155/2014/905472] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 06/11/2014] [Indexed: 01/17/2023]
Abstract
Oculocutaneous albinism (OCA) is an autosomal recessive disorder caused by either complete lack of or a reduction of melanin biosynthesis in the melanocytes. The OCA1A is the most severe type with a complete lack of melanin production throughout life, while the milder forms OCA1B, OCA2, OCA3, and OCA4 show some pigment accumulation over time. Mutations in TYR, OCA2, TYRP1, and SLC45A2 are mainly responsible for causing oculocutaneous albinism. Recently, two new genes SLC24A5 and C10orf11 are identified that are responsible to cause OCA6 and OCA7, respectively. Also a locus has been mapped to the human chromosome 4q24 region which is responsible for genetic cause of OCA5. In this paper, we summarized the clinical and molecular features of OCA genes. Further, we reviewed the screening of pathological mutations of OCA genes and its molecular mechanism of the protein upon mutation by in silico approach. We also reviewed TYR (T373K, N371Y, M370T, and P313R), OCA2 (R305W), TYRP1 (R326H and R356Q) mutations and their structural consequences at molecular level. It is observed that the pathological genetic mutations and their structural and functional significance of OCA genes will aid in development of personalized medicine for albinism patients.
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Karabas L, Esen F, Celiker H, Elcioglu N, Cerman E, Eraslan M, Kazokoglu H, Sahin O. Decreased subfoveal choroidal thickness and failure of emmetropisation in patients with oculocutaneous albinism. Br J Ophthalmol 2014; 98:1087-90. [DOI: 10.1136/bjophthalmol-2013-304766] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Montoliu L, Grønskov K, Wei AH, Martínez-García M, Fernández A, Arveiler B, Morice-Picard F, Riazuddin S, Suzuki T, Ahmed ZM, Rosenberg T, Li W. Increasing the complexity: new genes and new types of albinism. Pigment Cell Melanoma Res 2013; 27:11-8. [PMID: 24066960 DOI: 10.1111/pcmr.12167] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/08/2013] [Accepted: 09/17/2013] [Indexed: 12/24/2022]
Abstract
Albinism is a rare genetic condition globally characterized by a number of specific deficits in the visual system, resulting in poor vision, in association with a variable hypopigmentation phenotype. This lack or reduction in pigment might affect the eyes, skin, and hair (oculocutaneous albinism, OCA), or only the eyes (ocular albinism, OA). In addition, there are several syndromic forms of albinism (e.g. Hermansky-Pudlak and Chediak-Higashi syndromes, HPS and CHS, respectively) in which the described hypopigmented and visual phenotypes coexist with more severe pathological alterations. Recently, a locus has been mapped to the 4q24 human chromosomal region and thus represents an additional genetic cause of OCA, termed OCA5, while the gene is eventually identified. In addition, two new genes have been identified as causing OCA when mutated: SLC24A5 and C10orf11, and hence designated as OCA6 and OCA7, respectively. This consensus review, involving all laboratories that have reported these new genes, aims to update and agree upon the current gene nomenclature and types of albinism, while providing additional insights from the function of these new genes in pigment cells.
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Affiliation(s)
- Lluís Montoliu
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus de Cantoblanco, Madrid, Spain; CIBERER, ISCIII, Madrid, Spain
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Mauri L, Barone L, Al Oum M, Del Longo A, Piozzi E, Manfredini E, Stanzial F, Benedicenti F, Penco S, Patrosso MC. SLC45A2 mutation frequency in Oculocutaneous Albinism Italian patients doesn't differ from other European studies. Gene 2013; 533:398-402. [PMID: 24096233 DOI: 10.1016/j.gene.2013.09.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 08/02/2013] [Accepted: 09/16/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND Oculocutaneous Albinism (OCA) is a heterogeneous group of inherited diseases involving hair, skin and eyes. To date, six forms are recognized on the effects of different melanogenesis genes. OCA4 is caused by mutations in SLC45A2 showing a heterogeneous phenotype ranging from white hair, blue irides and nystagmus to brown/black hair, brown irides and no nystagmus. The high clinic variety often leads to misdiagnosis. Our aim is to contribute to OCA4 diagnosis defining SLC45A2 genetic variants in Italian patients with OCA without any TYR, OCA2 and TYRP1 gene defects. MATERIALS AND METHODS After the clinical diagnosis of OCA, all patients received genetic counseling and genetic test. Automatic sequencing of TYR, OCA2, and TYRP1 genes was performed on DNA of 117 albino patients. Multiplex Ligation-dependent Probe Amplification (MLPA) was carried out on TYR and OCA2 genes to increase the mutation rate. SLC45A2 gene sequencing was then executed in the patients with a single mutation in one of the TYR, OCA2, TYRP1 genes and in the patients, which resulted negative at the screening of these genes. RESULTS SLC45A2 gene analysis was performed in 41 patients and gene alterations were found in 5 patients. Four previously reported SLC45A2 mutations were found: p.G100S, p.W202C, p.A511E and c.986delC, and three novel variants were identified: p.M265L, p.H94D, and c.1156+1G>A. All the alterations have been detected in the group of patients without mutations in the other OCA genes. CONCLUSIONS Three new variants were identified in OCA4 gene; the analysis allowed the classification of a patient previously misdiagnosed as OA1 because of skin and hair pigmentation presence. The molecular defects in SLC45A2 gene represent the 3.4% in this cohort of Italian patients, similar to other Caucasian populations; our data differ from those previously published by an Italian researcher group, obtained on a smaller cohort of patients.
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Affiliation(s)
- Lucia Mauri
- Medical Genetics Unit, Niguarda Ca' Granda Hospital, Milan, Italy
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Grenga PL, Trabucco P, Meduri A, Fragiotta S, Vingolo EM. Microperimetric biofeedback in a patient with oculocutaneous albinism. Can J Ophthalmol 2013; 48:e105-7. [PMID: 24093197 DOI: 10.1016/j.jcjo.2012.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 11/26/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Pier Luigi Grenga
- University of Rome "Sapienza," Polo Pontino, "A. Fiorini" Hospital, Terracina (LT).
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kausar T, Bhatti MA, Ali M, Shaikh RS, Ahmed ZM. OCA5,a novel locus for non-syndromic oculocutaneous albinism, maps to chromosome 4q24. Clin Genet 2012; 84:91-3. [DOI: 10.1111/cge.12019] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - MA Bhatti
- Institute of Biotechnology; Bahauddin Zakariya University; Multan; Pakistan
| | - M Ali
- Institute of Biotechnology; Bahauddin Zakariya University; Multan; Pakistan
| | - RS Shaikh
- Institute of Biotechnology; Bahauddin Zakariya University; Multan; Pakistan
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Ko JM, Yang JA, Jeong SY, Kim HJ. Mutation spectrum of the TYR and SLC45A2 genes in patients with oculocutaneous albinism. Mol Med Rep 2012; 5:943-8. [PMID: 22294196 PMCID: PMC3493039 DOI: 10.3892/mmr.2012.764] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 01/11/2012] [Indexed: 12/24/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a group of inherited disorders characterized by defective melanin biosynthesis. OCA1, the most common and severe form, is caused by mutations in the tyrosinase (TYR) gene. OCA4, caused by mutations in the SLC45A2 gene, has frequently been reported in the Japanese population. To determine the mutational spectrum in Korean OCA patients, 12 patients were recruited. The samples were first screened for TYR mutations, and negative samples were screened for SLC45A2 mutations. OCA1 was confirmed in 8 of 12 (66.7%) patients, and OCA4 was diagnosed in 1 (8.3%) patient. In the OCA1 patients, a total of 6 distinct TYR mutations were found in 15 of 16 (93.8%) alleles, all of which had been previously reported. Out of the 6 alleles, c.929insC was the most frequently detected (31.3%), and was mainly associated with OCA1A phenotypes. Other TYR mutations identified included c.1037-7T>A/c.1037-10delTT, p.D383N, p.R77Q and p.R299H. These largely overlapped with mutations found in Japanese and Chinese patients. The SLC45A2 gene analysis identified 1 novel mutation, p.D93N, in 1 patient. This study has provided information on the mutation spectrum in Korean OCA patients, and allows us to estimate the relative frequencies of OCA1 and OCA4 in Korea.
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Affiliation(s)
- Jung Min Ko
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul 110-769, Republic of Korea.
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