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Gunz S, Rozen-Knisbacher I, Blumenfeld A, Hendler K, Yahalom C. The prevalence of autism among children with albinism. Eur J Ophthalmol 2024; 34:666-671. [PMID: 37787167 PMCID: PMC11067420 DOI: 10.1177/11206721231206091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 09/17/2023] [Indexed: 10/04/2023]
Abstract
BACKGROUND The association between Autism spectrum disorders (ASD) and visual impairment has been mentioned in the literature. The aim of our study was to investigate the prevalence of autism among children with albinism compared to the prevalence of ASD in children with visual impairment secondary to other causes. METHODS Retrospective study of children with albinism from January 2015 to December 2020. A control group was created with children with early onset visual impairment of similar visual range and age, secondary to diagnosis other than albinism. Patients with associated Autism were identified in both groups. RESULTS Seven hundred and eight children aged 1-18 years with visual impairment were included in the study. 401 children had a diagnosis of albinism, of whom 14 were also diagnosed with ASD. In the control group, composed of 307 patients, only 3 had ASD (p: 0·03). CONCLUSIONS The prevalence of ASD in patients with albinism was 1 in 28, while in children with visual impairment from other causes was 1 in 102. We aim to raise awareness of the higher prevalence of autism in children diagnosed with albinism in order to reach earlier diagnosis and support.
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Affiliation(s)
- Stav Gunz
- Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | | | - Anat Blumenfeld
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Karen Hendler
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Claudia Yahalom
- Faculty of Medicine, Hebrew University of Jerusalem, Israel
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
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2
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Zhang X, Wang S, Liu S, Du Z, Wu G, Liang Y, Huang Y, Shang X, Hu Y, Zhu Z, Sun W, Zhang X, Yu H. Epidemiologic association and shared genetic architecture between cataract and hearing difficulties among middle-aged and older adults. Hum Genomics 2024; 18:39. [PMID: 38632618 PMCID: PMC11022469 DOI: 10.1186/s40246-024-00601-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 03/20/2024] [Indexed: 04/19/2024] Open
Abstract
Age-related cataract and hearing difficulties are major sensory disorders that often co-exist in the global-wide elderly and have a tangible influence on the quality of life. However, the epidemiologic association between cataract and hearing difficulties remains unexplored, while little is known about whether the two share their genetic etiology. We first investigated the clinical association between cataract and hearing difficulties using the UK Biobank covering 502,543 individuals. Both unmatched analysis (adjusted for confounders) and a matched analysis (one control matched for each patient with cataract according to confounding factors) were undertaken and confirmed that cataract was associated with hearing difficulties (OR, 2.12; 95% CI, 1.98-2.27; OR, 2.03; 95% CI, 1.86-2.23, respectively). Furthermore, we explored and quantified the shared genetic architecture of these two complex sensory disorders at the common variant level using the bivariate causal mixture model (MiXeR) and conditional/conjunctional false discovery rate method based on the largest available genome-wide association studies of cataract (N = 585,243) and hearing difficulties (N = 323,978). Despite detecting only a negligible genetic correlation, we observe polygenic overlap between cataract and hearing difficulties and identify 6 shared loci with mixed directions of effects. Follow-up analysis of the shared loci implicates candidate genes QKI, STK17A, TYR, NSF, and TCF4 likely contribute to the pathophysiology of cataracts and hearing difficulties. In conclusion, this study demonstrates the presence of epidemiologic association between cataract and hearing difficulties and provides new insights into the shared genetic architecture of these two disorders at the common variant level.
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Affiliation(s)
- Xiayin Zhang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Shan Wang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Shunming Liu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zijing Du
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Guanrong Wu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yingying Liang
- Department of Ophthalmology, Guangzhou First people's Hospital, Guangzhou, China
| | - Yu Huang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xianwen Shang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yijun Hu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhuoting Zhu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, VIC, East Melbourne, Australia
| | - Wei Sun
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China.
| | - Xueli Zhang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China.
| | - Honghua Yu
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China.
- Guangdong Provincial Key Laboratory of Artificial Intelligence in Medical Image Analysis and Application, Guangzhou, China.
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3
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Yahalom C, Navarrete A, Juster A, Galbinur A, Blumenfeld A, Hendler K. Visual acuity improvement in children with albinism beyond the first decade of life. PLoS One 2024; 19:e0296744. [PMID: 38232104 DOI: 10.1371/journal.pone.0296744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 12/19/2023] [Indexed: 01/19/2024] Open
Abstract
PURPOSE To determine if visual maturation continues beyond the first decade of life in children with albinism and whether this is related to albinism type, presence of nystagmus, eye muscle surgery or refractive errors. DESIGN Case series based on retrospective study of children with confirmed genetic diagnosis of albinism. METHODS Clinical data were obtained from medical files of children examined during school years, including albinism type, visual acuity, eye muscle surgery, nystagmus, and others on different visits (Visit 1: ages 7-9; Visit 2: ages: 10-12; Visit 3: ages 13-16; Visit 4: ages >16). RESULTS Seventy-five children with albinism were included in the study. Patients were divided into different groups according to the albinism type including OCA1A: 17; OCA1B: 28; OCA2: 26; HPS: 3; OCA4: 1. Follow-up ranged from 3-13 years. Progressive visual acuity improvement was seen in all three main groups. T-test paired samples showed a statistically significant improvement when comparing vision from Visit 1 and Visit 3 in both OCA1A and OCA2 groups, with a mean vision improvement of 2 lines. There was no correlation between visual improvement and refractive error, eye muscle surgery or nystagmus. CONCLUSION An improved visual performance was seen in a large percentage of children with albinism during the second decade of life. The reason for this late improvement in vision is not clear but may be related to late foveal maturation or improvement in nystagmus with time. This information is useful for clinicians of these patients and when counseling parents.
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Affiliation(s)
- Claudia Yahalom
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Ana Navarrete
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Atara Juster
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Ayan Galbinur
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Anat Blumenfeld
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Karen Hendler
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
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4
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Osuna I, Dolinska MB, Sergeev YV. In Vitro Reconstitution of the Melanin Pathway's Catalytic Activities Using Tyrosinase Nanoparticles. Int J Mol Sci 2022; 24:639. [PMID: 36614088 PMCID: PMC9820814 DOI: 10.3390/ijms24010639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/24/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
The melanogenesis pathway is characterized by a series of reactions catalyzed by key enzymes, such as tyrosinase (TYR), tyrosinase-related protein 2 (TYRP2), and tyrosinase-related protein 1 (TYRP1), to produce melanin pigment. However, in vitro studies of the catalytic activity were incomplete because of a lack of commercially available enzyme substrates, such as dopachrome. Herein, human recombinant intra-melanosomal domains of key enzymes were produced in Trichoplusia ni (T. ni) larvae and then purified using a combination of chromatography techniques in catalytically active form. Using Michaelis-Menten kinetics, the diphenol oxidase activity of tyrosinase achieved the maximum production of native dopachrome at 10 min of incubation at 37 °C for TYR immobilized to magnetic beads (TYR-MB). The presence of dopachrome was confirmed spectrophotometrically at 475 nm through HPLC analysis and in the TYRP2-catalyzed reaction, yielding 5,6-dihydroxyindole-2-carboxylic acid (DHICA). In the TYRP1-driven oxidation of DHICA, the formation of 5,6-indolequinone-2-carboxylic acid (IQCA) was confirmed at ~560 nm. This is the first in vitro reconstitution of the reactions from the melanogenic pathway based on intra-melanosomal domains. In the future, this approach could be used for quantitative in vitro analysis of the melanin pathway, biochemical effects associated with inherited disease-related mutations, and drug screens.
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Affiliation(s)
| | | | - Yuri V. Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD 20891, USA
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The retinal pigmentation pathway in human albinism: Not so black and white. Prog Retin Eye Res 2022; 91:101091. [PMID: 35729001 DOI: 10.1016/j.preteyeres.2022.101091] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 12/16/2022]
Abstract
Albinism is a pigment disorder affecting eye, skin and/or hair. Patients usually have decreased melanin in affected tissues and suffer from severe visual abnormalities, including foveal hypoplasia and chiasmal misrouting. Combining our data with those of the literature, we propose a single functional genetic retinal signalling pathway that includes all 22 currently known human albinism disease genes. We hypothesise that defects affecting the genesis or function of different intra-cellular organelles, including melanosomes, cause syndromic forms of albinism (Hermansky-Pudlak (HPS) and Chediak-Higashi syndrome (CHS)). We put forward that specific melanosome impairments cause different forms of oculocutaneous albinism (OCA1-8). Further, we incorporate GPR143 that has been implicated in ocular albinism (OA1), characterised by a phenotype limited to the eye. Finally, we include the SLC38A8-associated disorder FHONDA that causes an even more restricted "albinism-related" ocular phenotype with foveal hypoplasia and chiasmal misrouting but without pigmentation defects. We propose the following retinal pigmentation pathway, with increasingly specific genetic and cellular defects causing an increasingly specific ocular phenotype: (HPS1-11/CHS: syndromic forms of albinism)-(OCA1-8: OCA)-(GPR143: OA1)-(SLC38A8: FHONDA). Beyond disease genes involvement, we also evaluate a range of (candidate) regulatory and signalling mechanisms affecting the activity of the pathway in retinal development, retinal pigmentation and albinism. We further suggest that the proposed pigmentation pathway is also involved in other retinal disorders, such as age-related macular degeneration. The hypotheses put forward in this report provide a framework for further systematic studies in albinism and melanin pigmentation disorders.
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Tingaud-Sequeira A, Mercier E, Michaud V, Pinson B, Gazova I, Gontier E, Decoeur F, McKie L, Jackson IJ, Arveiler B, Javerzat S. The Dct−/− Mouse Model to Unravel Retinogenesis Misregulation in Patients with Albinism. Genes (Basel) 2022; 13:genes13071164. [PMID: 35885947 PMCID: PMC9324463 DOI: 10.3390/genes13071164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 11/16/2022] Open
Abstract
We have recently identified DCT encoding dopachrome tautomerase (DCT) as the eighth gene for oculocutaneous albinism (OCA). Patients with loss of function of DCT suffer from eye hypopigmentation and retinal dystrophy. Here we investigate the eye phenotype in Dct−/− mice. We show that their retinal pigmented epithelium (RPE) is severely hypopigmented from early stages, contrasting with the darker melanocytic tissues. Multimodal imaging reveals specific RPE cellular defects. Melanosomes are fewer with correct subcellular localization but disrupted melanization. RPE cell size is globally increased and heterogeneous. P-cadherin labeling of Dct−/− newborn RPE reveals a defect in adherens junctions similar to what has been described in tyrosinase-deficient Tyrc/c embryos. The first intermediate of melanin biosynthesis, dihydroxyphenylalanine (L-Dopa), which is thought to control retinogenesis, is detected in substantial yet significantly reduced amounts in Dct−/− postnatal mouse eyecups. L-Dopa synthesis in the RPE alone remains to be evaluated during the critical period of retinogenesis. The Dct−/− mouse should prove useful in understanding the molecular regulation of retinal development and aging of the hypopigmented eye. This may guide therapeutic strategies to prevent vision deficits in patients with albinism.
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Affiliation(s)
- Angèle Tingaud-Sequeira
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
| | - Elina Mercier
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
| | - Vincent Michaud
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
- Molecular Genetics Laboratory, Bordeaux University Hospital, F-33076 Bordeaux, France
| | - Benoît Pinson
- SAM, TBMcore, CNRS UAR 3427, INSERM US005, Université Bordeaux, F-33076 Bordeaux, France;
| | - Ivet Gazova
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK; (I.G.); (L.M.); (I.J.J.)
| | - Etienne Gontier
- Bordeaux Imaging Center, CNRS, INSERM, BIC, UMS 3420, US 4, University Bordeaux, F-33076 Bordeaux, France; (E.G.); (F.D.)
| | - Fanny Decoeur
- Bordeaux Imaging Center, CNRS, INSERM, BIC, UMS 3420, US 4, University Bordeaux, F-33076 Bordeaux, France; (E.G.); (F.D.)
| | - Lisa McKie
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK; (I.G.); (L.M.); (I.J.J.)
| | - Ian J. Jackson
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK; (I.G.); (L.M.); (I.J.J.)
| | - Benoît Arveiler
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
- Molecular Genetics Laboratory, Bordeaux University Hospital, F-33076 Bordeaux, France
| | - Sophie Javerzat
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
- Correspondence:
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Ullah MI. Clinical and Mutation Spectrum of Autosomal Recessive Non-Syndromic Oculocutaneous Albinism (nsOCA) in Pakistan: A Review. Genes (Basel) 2022; 13:genes13061072. [PMID: 35741834 PMCID: PMC9222488 DOI: 10.3390/genes13061072] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 02/01/2023] Open
Abstract
Oculocutaneous albinism (OCA) is an autosomal recessive syndromic and non-syndromic defect with deficient or a complete lack of the melanin pigment. The characteristics of OCA appears in skin, hair, and eyes with variable degree of pigmentation. Clinical manifestations of OCA include nystagmus, photophobia, reduced visual acuity, hypo-plastic macula, and iris trans-illumination. There are eight OCA types (OCA1–8) documented with non-syndromic characteristics. Molecular studies identified seven genes linked to the OCA phenotype (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, C10orf11, and DCT) and one locus (OCA5) in consanguineous and sporadic albinism. The complications of OCA result in skin cancer and variable syndromes such as Hermansky–Pudlak syndrome (HPS) Chediak–Higashi syndrome (CHS). In the Pakistani population, autosomal recessive non-syndromic OCA is common and is associated with a large number of consanguineous families, and mutations in genes of non-syndromic types are reported. This review highlights the updates on the genetic mutation of OCA genes reported from Pakistani families. Several studies reported the genetic mutations in OCA1, OCA2, OCA3, OCA4, and OCA6 albinism in Pakistani families. A locus, OCA5, was also reported from the Pakistani population, but the gene has not been identified. A new type of OCA8 was identified due to the DCT gene mutation, and it is also reviewed here.
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Affiliation(s)
- Muhammad Ikram Ullah
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 75471, Aljouf, Saudi Arabia
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8
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Toufeeq S, Gottlob I, Tu Z, Proudlock FA, Pilat A. Abnormal Retinal Vessel Architecture in Albinism and Idiopathic Infantile Nystagmus. Invest Ophthalmol Vis Sci 2022; 63:33. [PMID: 35616929 PMCID: PMC9150830 DOI: 10.1167/iovs.63.5.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Infantile nystagmus syndrome (INS) causes altered visual development and can be associated with abnormal retinal structure, to which vascular development of the retina is closely related. Abnormal retinal vasculature has previously been noted in albinism but not idiopathic infantile nystagmus. We compared the number and diameter of retinal vessels in participants with albinism (PWA) and idiopathic infantile nystagmus (PWIIN) with controls. Methods Fundus photography data from 24 PWA, 10 PWIIN, and 34 controls was analyzed using Automated Retinal Image Analyzer (ARIA) software on a field of analysis centered on the optic disc, the annulus of which extended between 4.2 mm and 8.4 mm in diameter. Results Compared with controls, the mean number of arterial branches was reduced by 24% in PWA (15.5 vs. 20.3, P < 0.001), and venous branches were reduced in both PWA (29%; 12.9 vs. 18.2, P < 0.001) and PWIIN (17%; 15.1 vs. 18.2, P = 0.024). PWA demonstrated 7% thinner "primary" (before branching) arteries (mean diameter: 75.39 µm vs. 80.88 µm, P = 0.043), and 13% thicker (after branching) "secondary" veins (66.72 µm vs. 59.01 µm in controls, P = 0.009). Conclusions PWA and PWIIN demonstrated reduced retinal vessel counts and arterial diameters compared with controls. These changes in the superficial retinal vascular network may be secondary to underdevelopment of the neuronal network, which guides vascular development and is also known to be disrupted in INS.
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Affiliation(s)
- Shafak Toufeeq
- Oxford Eye Hospital, Level LG1 John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, United Kingdom
| | - Irene Gottlob
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
| | - Zhanhan Tu
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
| | - Frank A. Proudlock
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
| | - Anastasia Pilat
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University Of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
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Shakil M, Akbar A, Aisha NM, Hussain I, Ullah MI, Atif M, Kaul H, Amar A, Latif MZ, Qureshi MA, Mahmood S. Delineating Novel and Known Pathogenic Variants in TYR, OCA2 and HPS-1 Genes in Eight Oculocutaneous Albinism (OCA) Pakistani Families. Genes (Basel) 2022; 13:genes13030503. [PMID: 35328057 PMCID: PMC8950407 DOI: 10.3390/genes13030503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/24/2022] [Accepted: 03/08/2022] [Indexed: 12/10/2022] Open
Abstract
Oculocutaneous albinism (OCA) is associated with a wide range of clinical presentations and has been categorized with syndromic and non-syndromic features. The most common causative genes in non-syndromic OCA are TYR and OCA2 and HSP1 is in the syndromic albinism. The objective of this study was to identify pathogenic variants in congenital OCA families from Pakistan. Eight consanguineous families were recruited, and clinical and ophthalmological examination was carried out to diagnose the disease. Whole blood was collected from the participating individuals, and genomic DNA was extracted for sequencing analysis. TruSight one-panel sequencing was carried out on one affected individual of each family, and termination Sanger sequencing was carried out to establish the co-segregation of the causative gene or genes. In silico analysis was conducted to predict the causative pathogenic variants. Two families were found to have novel genetic pathogenic variants, and six families harbored previously reported variants. One novel compound heterozygous pathogenic variant in the TYR gene, c.1002delA; p.Ala335LeufsTer20, a novel frameshift deletion pathogenic variant and c.832C>T; and p.Arg278Ter (a known pathogenic variant) were found in one family, whereas HPS1; c.437G>A; and p.Trp146Ter were detected in another family. The identification of new and previous pathogenic variants in TYR, OCA2, and HPS1 genes are causative of congenital OCA, and these findings are expanding the heterogeneity of OCA.
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Affiliation(s)
- Muhammad Shakil
- Department of Biochemistry, University of Health Sciences (UHS), Lahore 54600, Pakistan;
- Department of Biochemistry, King Edward Medical University, Lahore 54000, Pakistan
| | - Abida Akbar
- Department of Biological Sciences, International Islamic University, Islamabad 44000, Pakistan;
| | - Nazish Mahmood Aisha
- Department of Biochemistry, Services Institute of Medical Sciences, Lahore 54600, Pakistan;
| | - Intzar Hussain
- Department of Ophthalmology Services, Institute of Medical Sciences, Lahore 54600, Pakistan;
| | - Muhammad Ikram Ullah
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 75471, Saudi Arabia; (M.I.U.); (M.A.)
| | - Muhammad Atif
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka 75471, Saudi Arabia; (M.I.U.); (M.A.)
| | - Haiba Kaul
- Genetics Discipline, Department of Animal Breeding and Genetics, Faculty of Animal Production and Technology, Ravi Campus, University of Veterinary and Animal Sciences, Pattoki 55300, Pakistan;
| | - Ali Amar
- Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore 54600, Pakistan;
| | - Muhammad Zahid Latif
- Department of Community Medicine and Medical Education, Azra Naheed Medical College, The Superior University, Lahore 54600, Pakistan; (M.Z.L.); (M.A.Q.)
| | - Muhammad Atif Qureshi
- Department of Community Medicine and Medical Education, Azra Naheed Medical College, The Superior University, Lahore 54600, Pakistan; (M.Z.L.); (M.A.Q.)
| | - Saqib Mahmood
- Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore 54600, Pakistan;
- Institute of Biomedical & Allied Health Sciences, University of Health Sciences Lahore, Lahore 54600, Pakistan
- Correspondence:
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Dolinska MB, Woods T, Osuna I, Sergeev YV. Protein Biochemistry and Molecular Modeling of the Intra-Melanosomal Domain of Human Recombinant Tyrp2 Protein and OCA8-Related Mutant Variants. Int J Mol Sci 2022; 23:ijms23031305. [PMID: 35163231 PMCID: PMC8836267 DOI: 10.3390/ijms23031305] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/14/2022] [Accepted: 01/20/2022] [Indexed: 12/27/2022] Open
Abstract
Tyrosinase-related protein 2 (Tyrp2) is involved in the melanogenesis pathway, catalyzing the tautomerization of dopachrome to 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Recently, a new type of albinism was discovered with disease-causing mutations in the TYRP2 gene. Here, for the first time, we characterized the intra-melanosomal protein domain of Tyrp2 (residues 1-474) and missense variants C40S and C61W, which mimic the alterations found in genetic studies. Recombinant proteins were produced in the Trichoplusia Ni (Ti. Ni) larvae, purified by a combination of immobilized metal affinity (IMAC) and gel-filtration (GF) chromatography, and biochemically characterized. The mutants showed the protein expression in the lysates such as the wild type; however, undetectable protein yield after two steps of purification exhibited their misfolding and instability. In addition, the misfolding effect of the mutations was confirmed computationally using homology modeling and molecular docking. Together, experiments in vitro and computer simulations indicated the critical role of the Cys-rich domain in the Tyrp2 protein stability. The results are consistent with molecular modeling, global computational mutagenesis, and clinical data, proving the significance of genetic alterations in cysteine residues, which could cause oculocutaneous albinism type 8.
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Zhang Z, Shen W, Liu W, Lyu L. Role of miRNAs in melanin metabolism: Implications in melanin-related diseases. J Cosmet Dermatol 2022; 21:4146-4159. [PMID: 35041756 DOI: 10.1111/jocd.14762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/02/2021] [Accepted: 01/05/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND MicroRNAs (miRNAs) are short single-stranded non-coding RNAs that regulate degradation and expression of messenger RNA (mRNA) and play a wide range of key roles in different biological processes. They mediate different stages of melanocyte differentiation, growth, and apoptosis through a variety of pathways and can mediate melanin production by targeting key enzymes. AIMS This article was aimed to review the role of miRNAs in melanin metabolism and to introduce the role and significance of miRNAs in melanin-related diseases. MATERIALS & METHODS Systematic search and retrospective review were performed on the published data. RESULTS This paper reviews the process of melanin synthesis and the regulatory mechanism, explores the miRNA expression profiles in different model organisms, and introduces the mechanisms of several key miRNAs participating in melanin metabolism through target genes. We also explore the potential role of miRNA as a new target for the treatment of melanin metabolism disease, including vitiligo, melanoma, and chloasma. CONCLUSION miRNAs play a key role in melanin-related diseases, and the miRNAs involved may be potential therapeutic targets.
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Affiliation(s)
- Zhigang Zhang
- Department of Dermatology, Affiliated Hospital of Yunnan University, Yunnan University, Kunming, China.,Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, China
| | - Wanlu Shen
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, China
| | - Weimin Liu
- Department of Dermatology, Affiliated Hospital of Yunnan University, Yunnan University, Kunming, China
| | - Lechun Lyu
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming, China
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