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Tao J, Luo J, Li K, Yang R, Lin Y, Ge J. Comprehensive genetic analysis uncovers the mutational spectrum of MFRP and its genotype-phenotype correlation in a large cohort of Chinese microphthalmia patients. Gene 2024; 926:148647. [PMID: 38848879 DOI: 10.1016/j.gene.2024.148647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/21/2024] [Accepted: 06/03/2024] [Indexed: 06/09/2024]
Abstract
PURPOSE Microphthalmia is a severe congenital ocular disease featured by abnormal ocular development. The aim of this study was to detail the genetic and clinical characteristics of a large cohort of Chinese patients with microphthalmia related to MFRP variants, focusing on uncovering genotype-phenotype correlations. METHODS Fifty microphthalmia patients from 44 unrelated Chinese families were recruited. Whole-exome sequencing (WES) was conducted to analyze the coding regions and adjacent intronic regions of MFRP. Axial lengths (AL) were measured for all probands and available family members. Protein structures of mutations with high frequency in our cohort were predicted. The genotype-phenotype correlations were explored by statistical analysis. RESULTS Sixteen MFRP variants were detected in 17 families, accounting for 38.64 % of all microphthalmia families. There were 9 novel mutations (c.427+1G>C, c.428-2A>C, c.561_575del:p.A188_E192del, c.836G>A:p.C279Y, c.1010_1021del:p.H337_E340del:p.Y479*, c.1516_1517del:p.S506Pfs*66, c.1561T>G:p.C521G, c.1616G>A:p.R539H, and c.1735C>T:p.P579S) and six previously reported variants in MFRP, with p.E496K and p.H337_E340del being highly frequent, found in eight (47.06 %) and two families (11.76 %), respectively. Seven variants (43.75 %) were located in the C-terminal cysteine-rich frizzled-related domain (CRD) (7/16, 43.75 %). Protein prediction implicated p.E496K and p.H337_E340del mutations might lead to a destabilization of the MFRP protein. The average AL of all 42 eyes was 16.02 ± 1.05 mm, and 78.36 % of eyes with AL < 16 mm harbored p.E496K variant. Twenty-six eyes with variant variant had shorter AL than that of the other 16 eyes without this variant (p = 0.006), highlighting a novel genotype-phenotype correlation. CONCLUSIONS In this largest cohort of Chinese patients with microphthalmia, the 9 novel variants, high frequency of p.E496W, and mutation hotspots in CRD reveals unique insights into the MFRP mutation spectrum among Chinese patients, indicating ethnic variability. A new genotype-phenotype correlation that p.E496K variant associated with a shorter AL is unveiled. Our findings enhance the current knowledge of MFRP-associated microphthalmia and provide valuable information for prenatal diagnosis as well as future therapy.
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Affiliation(s)
- Jing Tao
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing 100730, China
| | - Jingyi Luo
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, China
| | - Kaijing Li
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, China
| | - Runcai Yang
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, China
| | - Yixiu Lin
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, China
| | - Jian Ge
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong 510000, China.
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Plaisancié J, Martinovic J, Chesneau B, Whalen S, Rodriguez D, Audebert-Bellanger S, Marzin P, Grotto S, Perthus I, Holt RJ, Bax DA, Ragge N, Chassaing N. Clinical, genetic and biochemical signatures of RBP4-related ocular malformations. J Med Genet 2023; 61:84-92. [PMID: 37586836 DOI: 10.1136/jmg-2023-109331] [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: 07/16/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND The retinoic acid (RA) pathway plays a crucial role in both eye morphogenesis and the visual cycle. Individuals with monoallelic and biallelic pathogenic variants in retinol-binding protein 4 (RBP4), encoding a serum retinol-specific transporter, display variable ocular phenotypes. Although few families have been reported worldwide, recessive inherited variants appear to be associated with retinal degeneration, while individuals with dominantly inherited variants manifest ocular development anomalies, mainly microphthalmia, anophthalmia and coloboma (MAC). METHODS We report here seven new families (13 patients) with isolated and syndromic MAC harbouring heterozygous RBP4 variants, of whom we performed biochemical analyses. RESULTS For the first time, malformations that overlap the clinical spectrum of vitamin A deficiency are reported, providing a link with other RA disorders. Our data support two distinct phenotypes, depending on the nature and mode of inheritance of the variants: dominantly inherited, almost exclusively missense, associated with ocular malformations, in contrast to recessive, mainly truncating, associated with retinal degeneration. Moreover, we also confirm the skewed inheritance and impact of maternal RBP4 genotypes on phenotypical expression in dominant forms, suggesting that maternal RBP4 genetic status and content of diet during pregnancy may modify MAC occurrence and severity. Furthermore, we demonstrate that retinol-binding protein blood dosage in patients could provide a biological signature crucial for classifying RBP4 variants. Finally, we propose a novel hypothesis to explain the mechanisms underlying the observed genotype-phenotype correlations in RBP4 mutational spectrum. CONCLUSION Dominant missense variants in RBP4 are associated with MAC of incomplete penetrance with maternal inheritance through a likely dominant-negative mechanism.
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Affiliation(s)
- Julie Plaisancié
- Laboratoire National de Référence (LBMR), Génétique des anomalies malformatives de l'œil, CHU Toulouse, Toulouse, France
- Unité ToNIC Inserm 1214, CHU Toulouse, Toulouse, France
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), CHU Toulouse, Toulouse, France
| | - Jelena Martinovic
- Département de Génétique, Unité de Fœtopathologie, Hopital Necker-Enfants Malades, Paris, France
| | - Bertrand Chesneau
- Laboratoire National de Référence (LBMR), Génétique des anomalies malformatives de l'œil, CHU Toulouse, Toulouse, France
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), CHU Toulouse, Toulouse, France
| | - Sandra Whalen
- Genetique Medicale, Hopital Armand-Trousseau, Paris, France
| | - Diana Rodriguez
- Département de Génétique, Hôpitaux Universitaires Paris Ile-de-France Ouest, Paris, France
| | | | - Pauline Marzin
- Fédération de Génétique et Médecine Génomique, Service de Médecine Génomique des Maladies Rares, Necker-Enfants Malades Hospitals, Paris, France
| | - Sarah Grotto
- Maternité Port-Royal, FHU PREMA, Hôpital Cochin, Paris, France
| | - Isabelle Perthus
- Centre d'Etude des Malformations Congénitales en Auvergne, Génétique Médicale, CHU Estaing, Clermont-Ferrand, France
| | - Richard James Holt
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Dorine A Bax
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Nicola Ragge
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
- West Midlands Regional Genetics Service, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Nicolas Chassaing
- Laboratoire National de Référence (LBMR), Génétique des anomalies malformatives de l'œil, CHU Toulouse, Toulouse, France
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), CHU Toulouse, Toulouse, France
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3
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Wu W, Xu J, Yin H, Fu C, Yao K, Chen X. Heterozygous variants c.781G>A and c.1066dup of serine protease 56 cause familial nanophthalmos by impairing serine-type endopeptidase activity. Br J Ophthalmol 2023; 107:1750-1756. [PMID: 35383051 DOI: 10.1136/bjophthalmol-2021-320909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/24/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS Nanophthalmos is a rare developmental, bilateral, sporadic or hereditary form of microphthalmos. In this study, the heterozygous variants c.781G>A and c.1066dup of the PRSS56 gene were identified in two patients with nanophthalmos. This study reports the clinical manifestation and the underlying pathogenic mechanism. METHODS Whole-exome sequencing was performed to identify the pathogenic genes in a Chinese family with nanophthalmos. The molecular simulation was used to predict the structures of wild-type or mutant PRSS56. The PRSS56 wild-type or mutation overexpression cellular models have been constructed accordingly. The subcellular localisation was then observed using immunofluorescence and Western-blot techniques. The Folin-Ciocalteu assay was carried out to evaluate serine-type endopeptidase activity, and a wound-healing assay was used to examine the cellular migratory ability. RESULTS The whole-exome sequencing revealed that heterozygous variants c.781G>A and c.1066dup of the PRSS56 gene might contribute to nanophthalmos. Both variants were not identified in the dbSNP, 1000 Genome project or ESP6500 databases. Furthermore, the variants were highly conserved and were involved in biological functions. The mutations result in destructive protein structure and impede serine-type endopeptidase activity, thereby impairing subcellular localisation and cellular migration. CONCLUSION The c.781G>A and c.1066dup variants of the PRSS56 gene might negatively affect protein structures, subcellular localisation, serine-type endopeptidase activity and cellular migratory ability. Together, these changes could lead to the development of nanophthalmos. This study identifies the PRSS56 gene as a potential target for nanophthalmos diagnosis and treatment.
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Affiliation(s)
- Wei Wu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Houfa Yin
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Chenxi Fu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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Gholami Yarahmadi S, Sarlaki F, Morovvati S. Novel mutation in TENM3 gene in an Iranian patient with colobomatous microphthalmia. Clin Case Rep 2022; 10:e05532. [PMID: 35280100 PMCID: PMC8905136 DOI: 10.1002/ccr3.5532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/02/2022] [Accepted: 02/16/2022] [Indexed: 11/23/2022] Open
Abstract
This investigation revealed a homozygous c.5069-1G>C variation in TENM3 gene although has not been reported for its pathogenicity and can be considered as a novel mutation. The present finding can be used for genetic diagnosis and detection of carriers in the family and other patients with similar disease manifestations.
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Affiliation(s)
| | | | - Saeid Morovvati
- School of Advanced Sciences and TechnologyIslamic Azad University‐Tehran Medical SciencesTehranIran
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Novel Likely Pathogenic Variants Identified by Panel-Based Exome Sequencing in Congenital Cataract Patients. J Ophthalmol 2021; 2021:3847409. [PMID: 34840822 PMCID: PMC8612798 DOI: 10.1155/2021/3847409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/02/2021] [Indexed: 11/18/2022] Open
Abstract
Purpose To identify likely pathogenic variants in three families with congenital cataracts via panel-based exome sequencing. Methods A panel containing 153 genes associated with congenital cataracts was designed. Genes were selected through reference to databases including the Human Gene Mutation Database (HGMD), Online Mendelian Inheritance in Man (OMIM), Genetic Home Reference, and the latest peer-reviewed publications on the genetics of hereditary cataracts. Panel-based exome sequencing was performed with the Illumina HiSeq X-Ten platform, and then the identified variants were confirmed with Sanger sequencing and evaluated according to the American College of Medical Genetics and Genomics (ACMG) criteria. Results Three likely pathogenic variants were found. A novel CRYBB2: c.230G > T p.G77V variant was identified in family A, a novel CRYBB2: c.230G > A p.G77D variant was identified in family B, and a novel CRYGD: c.475delG p.A159Pfs∗9 variant was identified in family C. Conclusion Panel-based exome sequencing revealed three likely pathogenic variants in three unrelated Chinese families with congenital cataracts. These data expand the genetic spectrum associated with congenital cataracts.
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Rafati M, Mohamadhashem F, Jalilian K, Hoseininasab F, Fakhri L, Hoseini A, Amiri H, Barati Z, Darzi Ramandi S, Mostofinezhad N, Mahmoudi AH, Ghaffari SR. Identification of a novel de novo variant in OTX2 in a patient with congenital microphthalmia using targeted next-generation sequencing followed by prenatal diagnosis. Ophthalmic Genet 2021; 43:262-267. [PMID: 34791963 DOI: 10.1080/13816810.2021.2002915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Next-generation sequencing has been proven to be a reliable method for the detection of genetic causes in heterogeneous ocular disorders. In this report an NGS-based diagnostic approach was taken to uncover the genetic etiology in a patient with coloboma and microphthalmia, a highly heterogeneous disease with intrafamilial phenotypic variability. MATERIALS AND METHODS Next generation sequencing using a targeted panel of 316 genes, was carried out in the proband. Prioritized variants were then identified and confirmed using Sanger sequencing. Prenatal diagnosis of the detected variant was then performed in the family. RESULTS A novel de novo frameshift variant c.157_164delTTCACTCG (p.Phe53fs) in OTX2, leading to a truncated protein, was identified. Prenatal diagnosis identified the same variant in the fetus. CONCLUSIONS This report demonstrates the importance of genetic counseling and underscores the efficiency and effectiveness of targeted NGS as a means of detecting variants in inherited eye disorders.
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Affiliation(s)
- Maryam Rafati
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran.,Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.,Department of Genomics Gene Clinic, Tehran, Iran
| | - Faezeh Mohamadhashem
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Koosha Jalilian
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran
| | - Fatemeh Hoseininasab
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Laya Fakhri
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Azadeh Hoseini
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran
| | - Hosna Amiri
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran
| | - Zeinab Barati
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran
| | | | | | | | - Saeed Reza Ghaffari
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran.,Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.,Department of Genomics Gene Clinic, Tehran, Iran
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Chen D, Zhu S. Whole-exome sequencing identifies an RS1 variant in a Chinese family with X-linked retinoschisis. Exp Ther Med 2021; 22:1406. [PMID: 34675999 PMCID: PMC8524742 DOI: 10.3892/etm.2021.10842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/09/2021] [Indexed: 11/05/2022] Open
Abstract
A notable behavioural feature of X-linked retinoschisis (XLRS) is extensive structural schisis (splitting) of the outer plexiform and inner nuclear layers of the neurosensory retina, which is partly combined with complications related to vitreous hemorrhage, macular holes and retinal detachment. The present study aimed to identify the pathogenic gene mutation in a three-generation Chinese family with XLRS by whole-exome sequencing (WES). The clinical information of a three-generation Chinese family with cases of XLRS was collected. WES was performed for the proband. A comparison with the human reference genome sequence (hg38) and bioinformatic analysis were performed to reveal putative variants and Sanger sequencing was applied to verify mutations in this family and healthy control participants. Intraretinal cystic spaces were detected by optical coherence tomography imaging. Structures of the wild-type and mutant retinoschisin 1 (RS1) protein were modelled by PyMol. Almost all patients had a history of vision loss and abnormal blue-purple colour vision; however, the phenotypes of the 4 patients were distinctly different. There was no linear correlation between phenotypic severity and age. A recurrent RS1 (Xp22.2) mutation (NM_000330: c.559C>T) was detected, resulting in the p.Q187X variant. According to the protein model, this variant is likely pathogenic. The present study was the first to report that RS1:c.559C>T induces XLRS in a three-generation Chinese pedigree, with the mutation leading to premature termination of translation of the RS1 protein. WES was able to diagnose XLRS, which has the characteristics of clinical and genetic heterogeneity.
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Affiliation(s)
- Doudou Chen
- Eye School of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610075, P.R. China.,Department of Ophthalmology, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China.,Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China
| | - Siquan Zhu
- Eye School of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610075, P.R. China.,Department of Ophthalmology, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China.,Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China.,Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100006, P.R. China
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Harding P, Cunha DL, Moosajee M. Animal and cellular models of microphthalmia. THERAPEUTIC ADVANCES IN RARE DISEASE 2021; 2:2633004021997447. [PMID: 37181112 PMCID: PMC10032472 DOI: 10.1177/2633004021997447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/02/2021] [Indexed: 05/16/2023]
Abstract
Microphthalmia is a rare developmental eye disorder affecting 1 in 7000 births. It is defined as a small (axial length ⩾2 standard deviations below the age-adjusted mean) underdeveloped eye, caused by disruption of ocular development through genetic or environmental factors in the first trimester of pregnancy. Clinical phenotypic heterogeneity exists amongst patients with varying levels of severity, and associated ocular and systemic features. Up to 11% of blind children are reported to have microphthalmia, yet currently no treatments are available. By identifying the aetiology of microphthalmia and understanding how the mechanisms of eye development are disrupted, we can gain a better understanding of the pathogenesis. Animal models, mainly mouse, zebrafish and Xenopus, have provided extensive information on the genetic regulation of oculogenesis, and how perturbation of these pathways leads to microphthalmia. However, differences exist between species, hence cellular models, such as patient-derived induced pluripotent stem cell (iPSC) optic vesicles, are now being used to provide greater insights into the human disease process. Progress in 3D cellular modelling techniques has enhanced the ability of researchers to study interactions of different cell types during eye development. Through improved molecular knowledge of microphthalmia, preventative or postnatal therapies may be developed, together with establishing genotype-phenotype correlations in order to provide patients with the appropriate prognosis, multidisciplinary care and informed genetic counselling. This review summarises some key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future. Plain language summary Animal and Cellular Models of the Eye Disorder, Microphthalmia (Small Eye) Microphthalmia, meaning a small, underdeveloped eye, is a rare disorder that children are born with. Genetic changes or variations in the environment during the first 3 months of pregnancy can disrupt early development of the eye, resulting in microphthalmia. Up to 11% of blind children have microphthalmia, yet currently no treatments are available. By understanding the genes necessary for eye development, we can determine how disruption by genetic changes or environmental factors can cause this condition. This helps us understand why microphthalmia occurs, and ensure patients are provided with the appropriate clinical care and genetic counselling advice. Additionally, by understanding the causes of microphthalmia, researchers can develop treatments to prevent or reduce the severity of this condition. Animal models, particularly mice, zebrafish and frogs, which can also develop small eyes due to the same genetic/environmental changes, have helped us understand the genes which are important for eye development and can cause birth eye defects when disrupted. Studying a patient's own cells grown in the laboratory can further help researchers understand how changes in genes affect their function. Both animal and cellular models can be used to develop and test new drugs, which could provide treatment options for patients living with microphthalmia. This review summarises the key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future.
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Affiliation(s)
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, 11-43 Bath
Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
- Great Ormond Street Hospital for Children NHS
Foundation Trust, London, UK
- The Francis Crick Institute, London, UK
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9
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Ghosh S, Carden CF, Juras R, Mendoza MN, Jevit MJ, Castaneda C, Phelps O, Dube J, Kelley DE, Varner DD, Love CC, Raudsepp T. Two Novel Cases of Autosomal Translocations in the Horse: Warmblood Family Segregating t(4;30) and a Cloned Arabian with a de novo t(12;25). Cytogenet Genome Res 2020; 160:688-697. [PMID: 33326979 DOI: 10.1159/000512206] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/07/2020] [Indexed: 11/19/2022] Open
Abstract
We report 2 novel autosomal translocations in the horse. In Case 1, a breeding stallion with a balanced t(4p;30) had produced normal foals and those with congenital abnormalities. Of his 9 phenotypically normal offspring, 4 had normal karyotypes, 4 had balanced t(4p;30), and 1 carried an unbalanced translocation with tertiary trisomy of 4p. We argue that unbalanced forms of t(4p;30) are more tolerated and result in viable congenital abnormalities, without causing embryonic death like all other known equine autosomal translocations. In Case 2, two stallions produced by somatic cell nuclear transfer from the same donor were karyotyped because of fertility issues. A balanced translocation t(12q;25) was found in one, but not in the other clone. The findings underscore the importance of routine cytogenetic screening of breeding animals and animals produced by assisted reproductive technologies. These cases will contribute to molecular studies of translocation breakpoints and their genetic consequences in the horse.
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Affiliation(s)
- Sharmila Ghosh
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | | | - Rytis Juras
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Mayra N Mendoza
- Estación Experimental Agraria Chincha, Dirección de Recursos Genéticos y Biotecnología, Instituto Nacional de Innovación Agraria, Ica, Peru
| | - Matthew J Jevit
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Caitlin Castaneda
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Olivia Phelps
- Powder River Veterinary Hospital & Supply, Kaycee, Wyoming, USA
| | - Jessie Dube
- Powder River Veterinary Hospital & Supply, Kaycee, Wyoming, USA
| | - Dale E Kelley
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Dickson D Varner
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Charley C Love
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Terje Raudsepp
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA,
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PAX6 missense variants in two families with isolated foveal hypoplasia and nystagmus: evidence of paternal postzygotic mosaicism. Eur J Hum Genet 2020; 29:349-355. [PMID: 33024313 PMCID: PMC7868363 DOI: 10.1038/s41431-020-00737-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 09/15/2020] [Accepted: 09/22/2020] [Indexed: 12/15/2022] Open
Abstract
PAX6 is considered the master regulator of eye development, the majority of variants affecting this gene cause the pan-ocular developmental eye disorder aniridia. Although no genotype-phenotype correlations are clearly established, missense variants affecting the DNA-binding paired domain of PAX6 are usually associated with non-aniridia phenotypes like microphthalmia, coloboma or isolated foveal hypoplasia. In this study, we report two missense heterozygous variants in the paired domain of PAX6 resulting in isolated foveal hypoplasia with nystagmus in two independent families: c.112 C > G; p.(Arg38Gly) and c.214 G > C; p.(Gly72Arg) in exons 5 and 6, respectively. Furthermore, we provide evidence that paternal postzygotic mosaicism is the cause of inheritance, with clinically unaffected fathers and reduced affected allele fraction. This work contributes to increase the phenotypic spectrum caused by PAX6 variants, and to our knowledge, is the first report to describe the presence of postzygotic parental mosaicism causing isolated foveal hypoplasia with nystagmus. These results support the growing evidence that suggest an overestimation of sporadic cases with PAX6 variants, which has strong implications for both genetic counselling and family planning.
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11
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Harding P, Brooks BP, FitzPatrick D, Moosajee M. Anophthalmia including next-generation sequencing-based approaches. Eur J Hum Genet 2020; 28:388-398. [PMID: 31358957 PMCID: PMC7029013 DOI: 10.1038/s41431-019-0479-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/06/2019] [Accepted: 07/16/2019] [Indexed: 11/09/2022] Open
Abstract
Name of the disease (synonyms) See Table 1, Column 1-"Name of disease" and Column 2-"Alternative names". OMIM# of the disease See Table 1, Column 3-"OMIM# of the disease". Name of the analysed genes or DNA/chromosome segments and OMIM# of the gene(s) Core genes (irrespective of being tested by Sanger sequencing or next-generation sequencing): See Table 1, Column 4-"Cytogenetic location", Column 5-"Associated gene(s)" and Column 6-"OMIM# of associated gene(s)". Additional genes (if tested by next-generation sequencing, including Whole exome/genome sequencing and panel sequencing): See Table 2, Column 1-"Gene", Column 2-"Alternative names", Column 3-"OMIM# of gene" and Column 4-"Cytogenetic location". Review of the analytical and clinical validity as well as of the clinical utility of DNA-based testing for mutations in the gene(s) in diagnostic, predictive and prenatal settings, and for risk assessment in relatives.
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Affiliation(s)
| | - Brian P Brooks
- Ophthalmic Genetics & Visual Function Branch, National Eye Institute, Bethesda, MD, USA
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, UK. .,Moorfields Eye Hospital NHS Foundation Trust, London, UK. .,Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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12
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Wawrocka A, Walczak-Sztulpa J, Bukowska-Olech E, Jamsheer A, Jaworski M, Jaworski P, Krawczynski MR. Two sisters with microphthalmia and anterior segment dysgenesis secondary to a PAX6 pathogenic variant with clinically healthy parents: a case of gonadal mosaicism? Jpn J Ophthalmol 2020; 64:134-139. [DOI: 10.1007/s10384-020-00715-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 12/09/2019] [Indexed: 01/19/2023]
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13
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Méjécase C, Malka S, Guan Z, Slater A, Arno G, Moosajee M. Practical guide to genetic screening for inherited eye diseases. Ther Adv Ophthalmol 2020; 12:2515841420954592. [PMID: 33015543 PMCID: PMC7513416 DOI: 10.1177/2515841420954592] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/29/2020] [Indexed: 12/16/2022] Open
Abstract
Genetic eye diseases affect around one in 1000 people worldwide for which the molecular aetiology remains unknown in the majority. The identification of disease-causing gene variant(s) allows a better understanding of the disorder and its inheritance. There is now an approved retinal gene therapy for autosomal recessive RPE65-retinopathy, and numerous ocular gene/mutation-targeted clinical trials underway, highlighting the importance of establishing a genetic diagnosis so patients can fully access the latest research developments and treatment options. In this review, we will provide a practical guide to managing patients with these conditions including an overview of inheritance patterns, required pre- and post-test genetic counselling, different types of cytogenetic and genetic testing available, with a focus on next generation sequencing using targeted gene panels, whole exome and genome sequencing. We will expand on the pros and cons of each modality, variant interpretation and options for family planning for the patient and their family. With the advent of genomic medicine, genetic screening will soon become mainstream within all ophthalmology subspecialties for prevention of disease and provision of precision therapeutics.
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Affiliation(s)
- Cécile Méjécase
- Institute of Ophthalmology, University College
London, London, UK
| | - Samantha Malka
- Institute of Ophthalmology, University College
London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
| | - Zeyu Guan
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
| | - Amy Slater
- Royal Brompton and Harefield NHS Foundation
Trust, London, UK
| | - Gavin Arno
- Institute of Ophthalmology, University College
London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
- Great Ormond Street Hospital for Children NHS
Trust, London, UK
| | - Mariya Moosajee
- Professor, Institute of Ophthalmology,
University College London, 11-43 Bath Street, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
- Great Ormond Street Hospital for Children NHS
Trust, London, UK
- The Francis Crick Institute, London, UK
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14
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Lima Cunha D, Arno G, Corton M, Moosajee M. The Spectrum of PAX6 Mutations and Genotype-Phenotype Correlations in the Eye. Genes (Basel) 2019; 10:genes10121050. [PMID: 31861090 PMCID: PMC6947179 DOI: 10.3390/genes10121050] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/13/2022] Open
Abstract
The transcription factor PAX6 is essential in ocular development in vertebrates, being considered the master regulator of the eye. During eye development, it is essential for the correct patterning and formation of the multi-layered optic cup and it is involved in the developing lens and corneal epithelium. In adulthood, it is mostly expressed in cornea, iris, and lens. PAX6 is a dosage-sensitive gene and it is highly regulated by several elements located upstream, downstream, and within the gene. There are more than 500 different mutations described to affect PAX6 and its regulatory regions, the majority of which lead to PAX6 haploinsufficiency, causing several ocular and systemic abnormalities. Aniridia is an autosomal dominant disorder that is marked by the complete or partial absence of the iris, foveal hypoplasia, and nystagmus, and is caused by heterozygous PAX6 mutations. Other ocular abnormalities have also been associated with PAX6 changes, and genotype-phenotype correlations are emerging. This review will cover recent advancements in PAX6 regulation, particularly the role of several enhancers that are known to regulate PAX6 during eye development and disease. We will also present an updated overview of the mutation spectrum, where an increasing number of mutations in the non-coding regions have been reported. Novel genotype-phenotype correlations will also be discussed.
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Affiliation(s)
| | - Gavin Arno
- Institute of Ophthalmology, UCL, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Marta Corton
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital—Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Mariya Moosajee
- Institute of Ophthalmology, UCL, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- Correspondence:
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15
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Thompson B, Katsanis N, Apostolopoulos N, Thompson DC, Nebert DW, Vasiliou V. Genetics and functions of the retinoic acid pathway, with special emphasis on the eye. Hum Genomics 2019; 13:61. [PMID: 31796115 PMCID: PMC6892198 DOI: 10.1186/s40246-019-0248-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 11/12/2019] [Indexed: 02/07/2023] Open
Abstract
Retinoic acid (RA) is a potent morphogen required for embryonic development. RA is formed in a multistep process from vitamin A (retinol); RA acts in a paracrine fashion to shape the developing eye and is essential for normal optic vesicle and anterior segment formation. Perturbation in RA-signaling can result in severe ocular developmental diseases—including microphthalmia, anophthalmia, and coloboma. RA-signaling is also essential for embryonic development and life, as indicated by the significant consequences of mutations in genes involved in RA-signaling. The requirement of RA-signaling for normal development is further supported by the manifestation of severe pathologies in animal models of RA deficiency—such as ventral lens rotation, failure of optic cup formation, and embryonic and postnatal lethality. In this review, we summarize RA-signaling, recent advances in our understanding of this pathway in eye development, and the requirement of RA-signaling for embryonic development (e.g., organogenesis and limb bud development) and life.
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Affiliation(s)
- Brian Thompson
- Department of Environmental Health Sciences, Yale School of Public Health, 60 College St, New Haven, CT, 06520, USA
| | - Nicholas Katsanis
- Stanley Manne Research Institute, Lurie Children's Hospital, Chicago, IL, 60611, USA.,Departments of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Nicholas Apostolopoulos
- Department of Environmental Health Sciences, Yale School of Public Health, 60 College St, New Haven, CT, 06520, USA
| | - David C Thompson
- Department of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Daniel W Nebert
- Department of Environmental Health and Center for Environmental Genetics, University Cincinnati Medical Center, Cincinnati, OH, 45267-0056, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, 60 College St, New Haven, CT, 06520, USA.
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16
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Harding P, Moosajee M. The Molecular Basis of Human Anophthalmia and Microphthalmia. J Dev Biol 2019; 7:jdb7030016. [PMID: 31416264 PMCID: PMC6787759 DOI: 10.3390/jdb7030016] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 12/16/2022] Open
Abstract
Human eye development is coordinated through an extensive network of genetic signalling pathways. Disruption of key regulatory genes in the early stages of eye development can result in aborted eye formation, resulting in an absent eye (anophthalmia) or a small underdeveloped eye (microphthalmia) phenotype. Anophthalmia and microphthalmia (AM) are part of the same clinical spectrum and have high genetic heterogeneity, with >90 identified associated genes. By understanding the roles of these genes in development, including their temporal expression, the phenotypic variation associated with AM can be better understood, improving diagnosis and management. This review describes the genetic and structural basis of eye development, focusing on the function of key genes known to be associated with AM. In addition, we highlight some promising avenues of research involving multiomic approaches and disease modelling with induced pluripotent stem cell (iPSC) technology, which will aid in developing novel therapies.
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Affiliation(s)
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London EC1V 9EL, UK.
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK.
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK.
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17
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Nedelec B, Rozet JM, Fares Taie L. Genetic architecture of retinoic-acid signaling-associated ocular developmental defects. Hum Genet 2019; 138:937-955. [DOI: 10.1007/s00439-019-02052-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 07/23/2019] [Indexed: 12/14/2022]
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18
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Genetics of anophthalmia and microphthalmia. Part 1: Non-syndromic anophthalmia/microphthalmia. Hum Genet 2019; 138:799-830. [PMID: 30762128 DOI: 10.1007/s00439-019-01977-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/30/2019] [Indexed: 12/22/2022]
Abstract
Eye formation is the result of coordinated induction and differentiation processes during embryogenesis. Disruption of any one of these events has the potential to cause ocular growth and structural defects, such as anophthalmia and microphthalmia (A/M). A/M can be isolated or occur with systemic anomalies, when they may form part of a recognizable syndrome. Their etiology includes genetic and environmental factors; several hundred genes involved in ocular development have been identified in humans or animal models. In humans, around 30 genes have been repeatedly implicated in A/M families, although many other genes have been described in single cases or families, and some genetic syndromes include eye anomalies occasionally as part of a wider phenotype. As a result of this broad genetic heterogeneity, with one or two notable exceptions, each gene explains only a small percentage of cases. Given the overlapping phenotypes, these genes can be most efficiently tested on panels or by whole exome/genome sequencing for the purposes of molecular diagnosis. However, despite whole exome/genome testing more than half of patients currently remain without a molecular diagnosis. The proportion of undiagnosed cases is even higher in those individuals with unilateral or milder phenotypes. Furthermore, even when a strong gene candidate is available for a patient, issues of incomplete penetrance and germinal mosaicism make diagnosis and genetic counseling challenging. In this review, we present the main genes implicated in non-syndromic human A/M phenotypes and, for practical purposes, classify them according to the most frequent or predominant phenotype each is associated with. Our intention is that this will allow clinicians to rank and prioritize their molecular analyses and interpretations according to the phenotypes of their patients.
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19
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Tarilonte M, Morín M, Ramos P, Galdós M, Blanco-Kelly F, Villaverde C, Rey-Zamora D, Rebolleda G, Muñoz-Negrete FJ, Tahsin-Swafiri S, Gener B, Moreno-Pelayo MA, Ayuso C, Villamar M, Corton M. Parental Mosaicism in PAX6 Causes Intra-Familial Variability: Implications for Genetic Counseling of Congenital Aniridia and Microphthalmia. Front Genet 2018; 9:479. [PMID: 30386378 PMCID: PMC6199369 DOI: 10.3389/fgene.2018.00479] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 09/26/2018] [Indexed: 11/17/2022] Open
Abstract
Mutations in PAX6 are involved in several developmental eye disorders. These disorders have considerable phenotypic variability, ranging from panocular forms of congenital aniridia and microphthalmia to isolated anomalies of the anterior or posterior segment. Here, we describe 3 families with variable inter-generational ocular expression of aniridia, iris coloboma, or microphthalmia, and an unusual transmission of PAX6 mutations from an unaffected or mildly affected parent; all of which raised suspicion of gonosomal mosaicism. We first identified two previously known nonsense mutations and one novel likely pathogenic missense variant in PAX6 in probands by means of targeted NGS. The subsequent segregation analysis by Sanger sequencing evidenced the presence of highly probable mosaic events in paternal blood samples. Mosaicism was further confirmed by droplet digital PCR analysis in several somatic tissues of mosaic fathers. Quantification of the mutant allele fraction in parental samples showed a marked deviation from 50%, with a range between 12 and 29% depending on cell type. Gonosomal mosaicsm was definitively confirmed in one of the families thanks to the availability of a sperm sample from the mosaic father. Thus, the recurrence risk in this family was estimated to be about one-third. This is the first report confirming parental PAX6 mosaicism as a cause of disease recurrence in aniridia and other related phenotypes. In addition, we demonstrated that post-zygotic mosaicism is a frequent and underestimated pathogenic mechanism in aniridia, explaining intra-familial phenotypic variability in many cases. Our findings may have substantial implications for genetic counseling in congenital aniridia. Thus, we also highlight the importance of comprehensive genetic screening of parents for new sporadic cases with aniridia or related developmental eye disease to more accurately assess recurrence risk. In conclusion, somatic and/or gonosomal mosaicism should be taken into consideration as a genetic factor to explain not only families with unaffected parents despite multiple affected children but also variable expressivity, apparent de novo cases, and even uncharacterized cases of aniridia and related developmental eye disorders, apparently lacking PAX6 mutations.
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Affiliation(s)
- María Tarilonte
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain
| | - Matías Morín
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Patricia Ramos
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Galdós
- Department of Ophthalmology, Cruces University Hospital, Bilbao, Spain
| | - Fiona Blanco-Kelly
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Cristina Villaverde
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Dolores Rey-Zamora
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Gema Rebolleda
- Department of Glaucoma, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Francisco J Muñoz-Negrete
- Department of Glaucoma, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Saoud Tahsin-Swafiri
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Blanca Gener
- Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain.,Department of Genetics, BioCruces Health Research Institute, Cruces University Hospital, Bilbao, Spain
| | - Miguel-Angel Moreno-Pelayo
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Ayuso
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Manuela Villamar
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Corton
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
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20
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Matías-Pérez D, García-Montaño LA, Cruz-Aguilar M, García-Montalvo IA, Nava-Valdéz J, Barragán-Arevalo T, Villanueva-Mendoza C, Villarroel CE, Guadarrama-Vallejo C, la Cruz RVD, Chacón-Camacho O, Zenteno JC. Identification of novel pathogenic variants and novel gene-phenotype correlations in Mexican subjects with microphthalmia and/or anophthalmia by next-generation sequencing. J Hum Genet 2018; 63:1169-1180. [PMID: 30181649 DOI: 10.1038/s10038-018-0504-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/21/2018] [Accepted: 08/03/2018] [Indexed: 01/01/2023]
Abstract
Severe congenital eye malformations, particularly microphthalmia and anophthalmia, are one of the main causes of visual handicap worldwide. They can arise from multifactorial, chromosomal, or monogenic factors and can be associated with extensive clinical variability. Genetic analysis of individuals with these defects has allowed the recognition of dozens of genes whose mutations lead to disruption of normal ocular embryonic development. Recent application of next generation sequencing (NGS) techniques for genetic screening of patients with congenital eye defects has greatly improved the recognition of monogenic cases. In this study, we applied clinical exome NGS to a group of 14 Mexican patients (including 7 familial and 7 sporadic cases) with microphthalmia and/or anophthalmia. Causal or likely causal pathogenic variants were demonstrated in ~60% (8 out of 14 patients) individuals. Seven out of 8 different identified mutations occurred in well-known microphthalmia/anophthalmia genes (OTX2, VSX2, MFRP, VSX1) or in genes associated with syndromes that include ocular defects (CHD7, COL4A1) (including two instances of CHD7 pathogenic variants). A single pathogenic variant was identified in PIEZO2, a gene that was not previously associated with isolated ocular defects. NGS efficiently identified the genetic etiology of microphthalmia/anophthalmia in ~60% of cases included in this cohort, the first from Mexican origin analyzed to date. The molecular defects identified through clinical exome sequencing in this study expands the phenotypic spectra of CHD7-associated disorders and implicate PIEZO2 as a candidate gene for major eye developmental defects.
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Affiliation(s)
| | - Leopoldo A García-Montaño
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Marisa Cruz-Aguilar
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | | | - Jessica Nava-Valdéz
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Tania Barragán-Arevalo
- Department of Human Genetics, National Institute of Pediatrics of Mexico, Mexico City, Mexico
| | - Cristina Villanueva-Mendoza
- Department of Genetics, Hospital "Dr. Luis Sanchez Bulnes", Asociación Para Evitar la Ceguera en México, Mexico City, Mexico
| | - Camilo E Villarroel
- Department of Human Genetics, National Institute of Pediatrics of Mexico, Mexico City, Mexico
| | - Clavel Guadarrama-Vallejo
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Rocío Villafuerte-de la Cruz
- Ciencias Basicas, Escuela de Medicina, Instituto Tecnológico y de Estudios Superiores de Monterrey, Monterrey, NL, Mexico
| | - Oscar Chacón-Camacho
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Juan C Zenteno
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico. .,Department of Biochemistry, Faculty of Medicine, UNAM, Mexico City, Mexico.
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21
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AUDIOME: a tiered exome sequencing-based comprehensive gene panel for the diagnosis of heterogeneous nonsyndromic sensorineural hearing loss. Genet Med 2018; 20:1600-1608. [PMID: 29595809 DOI: 10.1038/gim.2018.48] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/13/2018] [Indexed: 01/25/2023] Open
Abstract
PURPOSE Hereditary hearing loss is highly heterogeneous. To keep up with rapidly emerging disease-causing genes, we developed the AUDIOME test for nonsyndromic hearing loss (NSHL) using an exome sequencing (ES) platform and targeted analysis for the curated genes. METHODS A tiered strategy was implemented for this test. Tier 1 includes combined Sanger and targeted deletion analyses of the two most common NSHL genes and two mitochondrial genes. Nondiagnostic tier 1 cases are subjected to ES and array followed by targeted analysis of the remaining AUDIOME genes. RESULTS ES resulted in good coverage of the selected genes with 98.24% of targeted bases at >15 ×. A fill-in strategy was developed for the poorly covered regions, which generally fell within GC-rich or highly homologous regions. Prospective testing of 33 patients with NSHL revealed a diagnosis in 11 (33%) and a possible diagnosis in 8 cases (24.2%). Among those, 10 individuals had variants in tier 1 genes. The ES data in the remaining nondiagnostic cases are readily available for further analysis. CONCLUSION The tiered and ES-based test provides an efficient and cost-effective diagnostic strategy for NSHL, with the potential to reflex to full exome to identify causal changes outside of the AUDIOME test.
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22
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Riera M, Wert A, Nieto I, Pomares E. Panel-based whole exome sequencing identifies novel mutations in microphthalmia and anophthalmia patients showing complex Mendelian inheritance patterns. Mol Genet Genomic Med 2017; 5:709-719. [PMID: 29178648 PMCID: PMC5702572 DOI: 10.1002/mgg3.329] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/21/2017] [Accepted: 07/27/2017] [Indexed: 12/15/2022] Open
Abstract
Background Microphthalmia and anophthalmia (MA) are congenital eye abnormalities that show an extremely high clinical and genetic complexity. In this study, we evaluated the implementation of whole exome sequencing (WES) for the genetic analysis of MA patients. This approach was used to investigate three unrelated families in which previous single‐gene analyses failed to identify the molecular cause. Methods A total of 47 genes previously associated with nonsyndromic MA were included in our panel. WES was performed in one affected patient from each family using the AmpliSeqTM Exome technology and the Ion ProtonTM platform. Results A novel heterozygous OTX2 missense mutation was identified in a patient showing bilateral anophthalmia who inherited the variant from a parent who was a carrier, but showed no sign of the condition. We also describe a new PAX6 missense variant in an autosomal‐dominant pedigree affected by mild bilateral microphthalmia showing high intrafamiliar variability, with germline mosaicism determined to be the most plausible molecular cause of the disease. Finally, a heterozygous missense mutation in RBP4 was found to be responsible in an isolated case of bilateral complex microphthalmia. Conclusion This study highlights that panel‐based WES is a reliable and effective strategy for the genetic diagnosis of MA. Furthermore, using this technique, the mutational spectrum of these diseases was broadened, with novel variants identified in each of the OTX2,PAX6, and RBP4 genes. Moreover, we report new cases of reduced penetrance, mosaicism, and variable phenotypic expressivity associated with MA, further demonstrating the heterogeneity of such disorders.
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Affiliation(s)
- Marina Riera
- Departament de Genètica, Institut de Microcirurgia Ocular (IMO), Barcelona, Spain
| | - Ana Wert
- Departament d'Oftalmologia Pediàtrica, Estrabisme i Neuroftalmologia, Institut de Microcirurgia Ocular (IMO), Barcelona, Spain
| | - Isabel Nieto
- Departament de Còrnia, Cataracta i Cirurgia Refractiva, Institut de Microcirurgia Ocular (IMO), Barcelona, Spain
| | - Esther Pomares
- Departament de Genètica, Institut de Microcirurgia Ocular (IMO), Barcelona, Spain
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