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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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Blue EE, Moore KJ, North KE, Desrosiers TA, Carmichael SL, White JJ, Chong JX, Bamshad MJ, Jenkins MM, Almli LM, Brody LC, Freedman SF, Reefhuis J, Romitti PA, Shaw GM, Werler M, Kay DM, Browne ML, Feldkamp ML, Finnell RH, Nembhard WN, Pangilinan F, Olshan AF. Exome sequencing identifies novel genes underlying primary congenital glaucoma in the National Birth Defects Prevention Study. Birth Defects Res 2024; 116:e2384. [PMID: 38990107 PMCID: PMC11245170 DOI: 10.1002/bdr2.2384] [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: 02/16/2024] [Revised: 06/07/2024] [Accepted: 06/25/2024] [Indexed: 07/12/2024]
Abstract
BACKGROUND Primary congenital glaucoma (PCG) affects approximately 1 in 10,000 live born infants in the United States (U.S.). PCG has a autosomal recessive inheritance pattern, and variable expressivity and reduced penetrance have been reported. Likely causal variants in the most commonly mutated gene, CYP1B1, are less prevalent in the U.S., suggesting that alternative genes may contribute to the condition. This study utilized exome sequencing to investigate the genetic architecture of PCG in the U.S. and to identify novel genes and variants. METHODS We studied 37 family trios where infants had PCG and were part of the National Birth Defects Prevention Study (births 1997-2011), a U.S. multicenter study of birth defects. Samples underwent exome sequencing and sequence reads were aligned to the human reference sample (NCBI build 37/hg19). Variant filtration was conducted under de novo and Mendelian inheritance models using GEMINI. RESULTS Among candidate variants, CYP1B1 was most represented (five trios, 13.5%). Twelve probands (32%) had potentially pathogenic variants in other genes not previously linked to PCG but important in eye development and/or to underlie Mendelian conditions with potential phenotypic overlap (e.g., CRYBB2, RXRA, GLI2). CONCLUSION Variation in the genes identified in this population-based study may help to further explain the genetics of PCG.
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Affiliation(s)
- Elizabeth E Blue
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, USA
- Brotman-Baty Institute for Precision Medicine, Seattle, Washington, USA
| | - Kristin J Moore
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Kari E North
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Tania A Desrosiers
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Suzan L Carmichael
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Janson J White
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Jessica X Chong
- Brotman-Baty Institute for Precision Medicine, Seattle, Washington, USA
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Michael J Bamshad
- Brotman-Baty Institute for Precision Medicine, Seattle, Washington, USA
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Division of Genetic Medicine, Seattle Children's Hospital, Seattle, Washington, USA
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington, USA
| | - Mary M Jenkins
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Lynn M Almli
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Lawrence C Brody
- Division of Genomics and Society, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Sharon F Freedman
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, USA
| | - Jennita Reefhuis
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Paul A Romitti
- Department of Epidemiology, College of Public Health, The University of Iowa, Iowa City, Iowa, USA
| | - Gary M Shaw
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Martha Werler
- Department of Epidemiology, School of Public Health, Boston University, Boston, Massachusetts, USA
- Slone Epidemiology Center at Boston University, Boston, Massachusetts, USA
| | - Denise M Kay
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Marilyn L Browne
- New York State Department of Health, Birth Defects Registry, Albany, New York, USA
- Department of Epidemiology and Biostatistics, University at Albany School of Public Health, Rensselaer, New York, USA
| | - Marcia L Feldkamp
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Richard H Finnell
- Center for Precision Environmental Health, Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Wendy N Nembhard
- Department of Epidemiology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Faith Pangilinan
- Division of Genomics and Society, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew F Olshan
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Kukulka NA, Zarei S, Glass J, Bouska C, Schroder J, Sen K. COL4A1-related disorder as a mimic of congenital TORCHES infection-Expanding the clinical, neuroimaging and genotype spectrum. Am J Med Genet A 2024:e63804. [PMID: 38942733 DOI: 10.1002/ajmg.a.63804] [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: 04/02/2024] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/30/2024]
Abstract
Pseudo-TORCH Syndrome (PTS) encompasses a heterogeneous group of genetic disorders that may clinically and radiologically resemble congenital TORCH infections. These mimickers present with overlapping features manifested as intracranial and systemic abnormalities. Collagen type IV alpha 1 chain (COL4A1)-related diseases, characterized by autosomal dominant inheritance, exhibit a diverse phenotypic spectrum involving cerebrovascular, renal, ophthalmological, cardiac, and muscular abnormalities. Cerebrovascular manifestations range from small-vessel brain disease to large vessel abnormalities, resulting in intracerebral hemorrhage, periventricular leukoencephalopathy, and ventriculomegaly. Additional features include cortical malformations, eye defects, arrhythmias, renal disease, muscular abnormalities, and hematological manifestations. Age of onset varies widely, and phenotypic variability exists even among individuals with the same variant. In this study, we present two cases of COL4A1-related disorder mimicking congenital TORCH infections, highlighting the importance of recognizing genetic mimics in clinical practice.
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Affiliation(s)
- Natalie A Kukulka
- Child Neurology Fellow, Neurology Department, Children's National Hospital, Washington, DC, USA
| | - Sanam Zarei
- Child Neurology Fellow, Neurology Department, Children's National Hospital, Washington, DC, USA
| | - Joshua Glass
- Hematology/Oncology Fellow, Center for Cancer & Blood Disorders, Children's National Hospital, Washington, DC, USA
| | - Cecilia Bouska
- Genetic Counselor, Neurogenetics Department, Children's National Hospital, Washington, DC, USA
| | - Jason Schroder
- Neuroradiologist, Radiology Department, Children's National Hospital, Washington, DC, USA
| | - Kuntal Sen
- Neurogenetics Clinic Co-Director, Center for Neuroscience and Behavioral Medicine, Washington, DC, USA
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Eintracht J, Owen N, Harding P, Moosajee M. Disruption of common ocular developmental pathways in patient-derived optic vesicle models of microphthalmia. Stem Cell Reports 2024; 19:839-858. [PMID: 38821055 DOI: 10.1016/j.stemcr.2024.05.001] [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: 09/13/2023] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 06/02/2024] Open
Abstract
Genetic perturbations influencing early eye development can result in microphthalmia, anophthalmia, and coloboma (MAC). Over 100 genes are associated with MAC, but little is known about common disease mechanisms. In this study, we generated induced pluripotent stem cell (iPSC)-derived optic vesicles (OVs) from two unrelated microphthalmia patients and healthy controls. At day 20, 35, and 50, microphthalmia patient OV diameters were significantly smaller, recapitulating the "small eye" phenotype. RNA sequencing (RNA-seq) analysis revealed upregulation of apoptosis-initiating and extracellular matrix (ECM) genes at day 20 and 35. Western blot and immunohistochemistry revealed increased expression of lumican, nidogen, and collagen type IV, suggesting ECM overproduction. Increased apoptosis was observed in microphthalmia OVs with reduced phospho-histone 3 (pH3+) cells confirming decreased cell proliferation at day 35. Pharmacological inhibition of caspase-8 activity with Z-IETD-FMK decreased apoptosis in one patient model, highlighting a potential therapeutic approach. These data reveal shared pathophysiological mechanisms contributing to a microphthalmia phenotype.
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Affiliation(s)
| | | | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; Moorfields Eye Hospital NHS Foundation Trust, London EC1V 9EL, UK; Francis Crick Institute, London NW1 1AT, UK.
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Bai T, Shen Y, Yang Y, Dai S, Liu H. Maternal CHD7 gonosomal mosaicism in a fetus with CHARGE syndrome. Am J Med Genet A 2024; 194:e63491. [PMID: 38057991 DOI: 10.1002/ajmg.a.63491] [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: 08/30/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 12/08/2023]
Abstract
Parental mosaicism is important in families with de novo mutations. Herein, we report a case of fetal CHARGE syndrome (CS) with a CHD7 variant inherited from maternal CHD7 gonosomal mosaicism. The variant was detected through trio-based whole-exome sequencing and Sanger sequencing. High-depth whole-exome sequencing was performed for the identification of parental mosaicism. A novel heterozygous CHD7 nonsense mutation (c.5794G>T/ p.E1932*) was detected in the tissue from the aborted fetus. The parents were wild-type, indicating that the mutation was a de novo variant. The mutation was suspected to be the cause of the fetal CS. However, high-depth whole-exome sequencing revealed maternal gonosomal mosaicism at a variant allele frequency of 3.2%-23.3%. The variant was identified in various tissues (peripheral blood, hair follicles, buccal epithelia, and pharyngeal epithelia) from the asymptomatic mother. We confirmed maternal CHD7 gonosomal mosaicism as a genetic cause of fetal CS. Our results emphasize the importance of clinical analysis in accurately determining the parents' status in detecting the CHD7 de novo variant in fetal CS, as this analysis has vital implications for evaluating the recurrence risk for genetic counseling.
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Affiliation(s)
- Ting Bai
- Department of Medical Genetics, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Ying Shen
- Department of Obstetrics/Gynecology, Joint Laboratory of Reproductive Medicine (SCU-CUHK), Key Laboratory of Obstetric, Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yanting Yang
- Department of Medical Genetics, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Siyu Dai
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Hongqian Liu
- Department of Medical Genetics, West China Second University Hospital, Sichuan University, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
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Jackson D, Moosajee M. The Genetic Determinants of Axial Length: From Microphthalmia to High Myopia in Childhood. Annu Rev Genomics Hum Genet 2023; 24:177-202. [PMID: 37624667 DOI: 10.1146/annurev-genom-102722-090617] [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] [Indexed: 08/27/2023]
Abstract
The axial length of the eye is critical for normal visual function by enabling light to precisely focus on the retina. The mean axial length of the adult human eye is 23.5 mm, but the molecular mechanisms regulating ocular axial length remain poorly understood. Underdevelopment can lead to microphthalmia (defined as a small eye with an axial length of less than 19 mm at 1 year of age or less than 21 mm in adulthood) within the first trimester of pregnancy. However, continued overgrowth can lead to axial high myopia (an enlarged eye with an axial length of 26.5 mm or more) at any age. Both conditions show high genetic and phenotypic heterogeneity associated with significant visual morbidity worldwide. More than 90 genes can contribute to microphthalmia, and several hundred genes are associated with myopia, yet diagnostic yields are low. Crucially, the genetic pathways underpinning the specification of eye size are only now being discovered, with evidence suggesting that shared molecular pathways regulate under- or overgrowth of the eye. Improving our mechanistic understanding of axial length determination will help better inform us of genotype-phenotype correlations in both microphthalmia and myopia, dissect gene-environment interactions in myopia, and develop postnatal therapies that may influence overall eye growth.
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Affiliation(s)
- Daniel Jackson
- Institute of Ophthalmology, University College London, London, United Kingdom;
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, London, United Kingdom;
- The Francis Crick Institute, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
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Hendargo KJ, Patel AO, Chukwudozie OS, Moreno-Hagelsieb G, Christen JA, Medrano-Soto A, Saier MH. Sequence Similarity among Structural Repeats in the Piezo Family of Mechanosensitive Ion Channels. Microb Physiol 2023; 33:49-62. [PMID: 37321192 PMCID: PMC11283329 DOI: 10.1159/000531468] [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: 12/01/2022] [Accepted: 06/05/2023] [Indexed: 06/17/2023]
Abstract
Members of the Piezo family of mechanically activated cation channels are involved in multiple physiological processes in higher eukaryotes, including vascular development, cell differentiation, touch perception, hearing, and more, but they are also common in single-celled eukaryotic microorganisms. Mutations in these proteins in humans are associated with a variety of diseases, such as colorectal adenomatous polyposis, dehydrated hereditary stomatocytosis, and hereditary xerocytosis. Available 3D structures for Piezo proteins show nine regions of four transmembrane segments each that have the same fold. Despite the remarkable similarity among the nine characteristic structural repeats in the family, no significant sequence similarity among them has been reported. Using bioinformatics approaches and the Transporter Classification Database (TCDB) as reference, we reliably identified sequence similarity among repeats based on four lines of evidence: (1) hidden Markov model-profile similarities across repeats at the family level, (2) pairwise sequence similarities between different repeats across Piezo homologs, (3) Piezo-specific conserved sequence signatures that consistently identify the same regions across repeats, and (4) conserved residues that maintain the same orientation and location in 3D space.
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Affiliation(s)
- Kevin J. Hendargo
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, CA, USA
| | - Ashay O. Patel
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, CA, USA
| | - Onyeka S. Chukwudozie
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, CA, USA
| | | | - J. Andrés Christen
- Departamento de Probabilidad y Estadística, Centro de Investigación en Matemáticas, CIMAT, Guanajuato, Mexico
| | - Arturo Medrano-Soto
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, CA, USA
| | - Milton H. Saier
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, CA, USA
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Prenatal diagnosis of distal 13q deletion syndrome in a fetus with esophageal atresia: a case report and review of the literature. J Med Case Rep 2022; 16:481. [PMID: 36572904 PMCID: PMC9793530 DOI: 10.1186/s13256-022-03713-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 12/07/2022] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Chromosome 13q deletion syndrome shows variable clinical features related to the different potential breakpoints in chromosome 13q. The severely malformed phenotype is known to be associated with the deletion of a critical region in 13q32. However, esophageal atresia is a rare symptom and the relevant region is unknown. Thus, determining the association between accurate breakpoints and new clinical features is essential. CASE PRESENTATION A 28-year-old Japanese primigravid woman was referred for fetal growth restriction, absence of a gastric bubble, cerebellar hypoplasia, overlapping fingers, and polyhydramnios at 31 weeks gestation. At 38 + 0 weeks, she delivered a 1774 g female infant. The infant presented with isolated esophageal atresia (Gross type A), Dandy-Walker malformation, right microphthalmia, left coloboma, overlapping fingers, pleurocentrum in the thoracic vertebrae, reduced anogenital distance, and hearing loss. Her karyotype was diagnosed as 46,XX,del(13)(q32.1-qter) by amniocentesis, but array comparative genomic hybridization after birth revealed the deletion of 13q31.3-qter. At 48 days after birth, the infant underwent surgery for esophageal atresia and was later discharged from the hospital at 7 months of age. CONCLUSION This case report and the literature reviews supports the previous findings on the pathological roles of haploinsufficiency of the ZIC2/ZIC5 in Dandy-Walker malformation and the EFBN2 haploinsufficiency in eye malformation and hearing loss. Furthermore, the possible involvement of IRS2, COLA1, and COLA2 in eye malformation were identified. This is the first case of 13q deletion syndrome with esophageal atresia (Gross A), but it may be a symptom of VATER/VACTER association (vertebral defects, anorectal malformations, cardiac defects, tracheoesophageal fistula with or without esophageal atresia, renal malformations, and limb defects), as in the previous cases. These symptoms might also be associated with EFBN2 haploinsufficiency, although further research is required.
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Diacou R, Nandigrami P, Fiser A, Liu W, Ashery-Padan R, Cvekl A. Cell fate decisions, transcription factors and signaling during early retinal development. Prog Retin Eye Res 2022; 91:101093. [PMID: 35817658 PMCID: PMC9669153 DOI: 10.1016/j.preteyeres.2022.101093] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/30/2022]
Abstract
The development of the vertebrate eyes is a complex process starting from anterior-posterior and dorso-ventral patterning of the anterior neural tube, resulting in the formation of the eye field. Symmetrical separation of the eye field at the anterior neural plate is followed by two symmetrical evaginations to generate a pair of optic vesicles. Next, reciprocal invagination of the optic vesicles with surface ectoderm-derived lens placodes generates double-layered optic cups. The inner and outer layers of the optic cups develop into the neural retina and retinal pigment epithelium (RPE), respectively. In vitro produced retinal tissues, called retinal organoids, are formed from human pluripotent stem cells, mimicking major steps of retinal differentiation in vivo. This review article summarizes recent progress in our understanding of early eye development, focusing on the formation the eye field, optic vesicles, and early optic cups. Recent single-cell transcriptomic studies are integrated with classical in vivo genetic and functional studies to uncover a range of cellular mechanisms underlying early eye development. The functions of signal transduction pathways and lineage-specific DNA-binding transcription factors are dissected to explain cell-specific regulatory mechanisms underlying cell fate determination during early eye development. The functions of homeodomain (HD) transcription factors Otx2, Pax6, Lhx2, Six3 and Six6, which are required for early eye development, are discussed in detail. Comprehensive understanding of the mechanisms of early eye development provides insight into the molecular and cellular basis of developmental ocular anomalies, such as optic cup coloboma. Lastly, modeling human development and inherited retinal diseases using stem cell-derived retinal organoids generates opportunities to discover novel therapies for retinal diseases.
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Affiliation(s)
- Raven Diacou
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Prithviraj Nandigrami
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Andras Fiser
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wei Liu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Ales Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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Li J, Yang W, Wang YJ, Ma C, Curry CJ, McGoldrick D, Nickerson DA, Chong JX, Blue EE, Mullikin JC, Reefhuis J, Nembhard WN, Romitti PA, Werler MM, Browne ML, Olshan AF, Finnell RH, Feldkamp ML, Pangilinan F, Almli LM, Bamshad MJ, Brody LC, Jenkins MM, Shaw GM. Exome sequencing identifies genetic variants in anophthalmia and microphthalmia. Am J Med Genet A 2022; 188:2376-2388. [PMID: 35716026 PMCID: PMC9283271 DOI: 10.1002/ajmg.a.62874] [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: 11/09/2021] [Revised: 02/24/2022] [Accepted: 03/02/2022] [Indexed: 11/10/2022]
Abstract
Anophthalmia and microphthalmia (A/M) are rare birth defects affecting up to 2 per 10,000 live births. These conditions are manifested by the absence of an eye or reduced eye volumes within the orbit leading to vision loss. Although clinical case series suggest a strong genetic component in A/M, few systematic investigations have been conducted on potential genetic contributions owing to low population prevalence. To overcome this challenge, we utilized DNA samples and data collected as part of the National Birth Defects Prevention Study (NBDPS). The NBDPS employed multi-center ascertainment of infants affected by A/M. We performed exome sequencing on 67 family trios and identified numerous genes affected by rare deleterious nonsense and missense variants in this cohort, including de novo variants. We identified 9 nonsense changes and 86 missense variants that are absent from the reference human population (Genome Aggregation Database), and we suggest that these are high priority candidate genes for A/M. We also performed literature curation, single cell transcriptome comparisons, and molecular pathway analysis on the candidate genes and performed protein structure modeling to determine the potential pathogenic variant consequences on PAX6 in this disease.
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Affiliation(s)
- Jingjing Li
- Department of Neurology School of Medicine, The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, The Bakar Computational Health Sciences Institute, The Parker Institute for Cancer Immunotherapy, University of California San Francisco, San Francisco, California, USA
| | - Wei Yang
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Yuejun Jessie Wang
- Department of Neurology School of Medicine, The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, The Bakar Computational Health Sciences Institute, The Parker Institute for Cancer Immunotherapy, University of California San Francisco, San Francisco, California, USA
| | - Chen Ma
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Cynthia J Curry
- Genetic Medicine, Department of Pediatrics, University of California, San Francisco, California, USA
| | - Daniel McGoldrick
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA.,Brotman Baty Institute for Precision Medicine, Seattle, Washington, USA
| | - Jessica X Chong
- Brotman Baty Institute for Precision Medicine, Seattle, Washington, USA.,Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Elizabeth E Blue
- Brotman Baty Institute for Precision Medicine, Seattle, Washington, USA.,Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - James C Mullikin
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jennita Reefhuis
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Wendy N Nembhard
- Department of Epidemiology, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Paul A Romitti
- Department of Epidemiology, University of Iowa College of Public Health, Iowa City, Iowa, USA
| | - Martha M Werler
- Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA
| | - Marilyn L Browne
- Birth Defects Registry, New York State Department of Health, Albany, New York, USA.,Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, Rensselaer, New York, USA
| | - Andrew F Olshan
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Richard H Finnell
- Department of Molecular and Cellular Biology, Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular and Human Genetics, Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA.,Department of Medicine, Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas, USA
| | - Marcia L Feldkamp
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Faith Pangilinan
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Lynn M Almli
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Mike J Bamshad
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA.,Brotman Baty Institute for Precision Medicine, Seattle, Washington, USA.,Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Lawrence C Brody
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Mary M Jenkins
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Gary M Shaw
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
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- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland, USA
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- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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11
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Mao M, Labelle-Dumais C, Tufa SF, Keene DR, Gould DB. Elevated TGFβ signaling contributes to ocular anterior segment dysgenesis in Col4a1 mutant mice. Matrix Biol 2022; 110:151-173. [PMID: 35525525 PMCID: PMC10410753 DOI: 10.1016/j.matbio.2022.05.001] [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: 12/21/2021] [Revised: 04/08/2022] [Accepted: 05/02/2022] [Indexed: 10/18/2022]
Abstract
Ocular anterior segment dysgenesis (ASD) refers to a collection of developmental disorders affecting the anterior structures of the eye. Although a number of genes have been implicated in the etiology of ASD, the underlying pathogenetic mechanisms remain unclear. Mutations in genes encoding collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause Gould syndrome, a multi-system disorder that often includes ocular manifestations such as ASD and glaucoma. COL4A1 and COL4A2 are abundant basement membrane proteins that provide structural support to tissues and modulate signaling through interactions with other extracellular matrix proteins, growth factors, and cell surface receptors. In this study, we used a combination of histological, molecular, genetic and pharmacological approaches to demonstrate that altered TGFβ signaling contributes to ASD in mouse models of Gould syndrome. We show that TGFβ signaling was elevated in anterior segments from Col4a1 mutant mice and that genetically reducing TGFβ signaling partially prevented ASD. Notably, we identified distinct roles for TGFβ1 and TGFβ2 in ocular defects observed in Col4a1 mutant mice. Importantly, we show that pharmacologically promoting type IV collagen secretion or reducing TGFβ signaling ameliorated ocular pathology in Col4a1 mutant mice. Overall, our findings demonstrate that altered TGFβ signaling contributes to COL4A1-related ocular dysgenesis and implicate this pathway as a potential therapeutic target for the treatment of Gould syndrome.
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Affiliation(s)
- Mao Mao
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, United States
| | - Cassandre Labelle-Dumais
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, United States
| | - Sara F Tufa
- Shriners Children's, Micro-Imaging Center, Portland, Oregon 97239, United States
| | - Douglas R Keene
- Shriners Children's, Micro-Imaging Center, Portland, Oregon 97239, United States
| | - Douglas B Gould
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, United States; Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, United States; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, United States; Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, United States; Bakar Aging Research Institute, University of California, San Francisco, San Francisco, CA 94143, United States.
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12
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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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13
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Plotnikov D, Cui J, Clark R, Wedenoja J, Pärssinen O, Tideman JWL, Jonas JB, Wang Y, Rudan I, Young TL, Mackey DA, Terry L, Williams C, Guggenheim JA. Genetic Variants Associated With Human Eye Size Are Distinct From Those Conferring Susceptibility to Myopia. Invest Ophthalmol Vis Sci 2021; 62:24. [PMID: 34698770 PMCID: PMC8556552 DOI: 10.1167/iovs.62.13.24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purpose Emmetropization requires coordinated scaling of the major ocular components, corneal curvature and axial length. This coordination is achieved in part through a shared set of genetic variants that regulate eye size. Poorly coordinated scaling of corneal curvature and axial length results in refractive error. We tested the hypothesis that genetic variants regulating eye size in emmetropic eyes are distinct from those conferring susceptibility to refractive error. Methods A genome-wide association study (GWAS) for corneal curvature in 22,180 adult emmetropic individuals was performed as a proxy for a GWAS for eye size. A polygenic score created using lead GWAS variants was tested for association with corneal curvature and axial length in an independent sample: 437 classified as emmetropic and 637 as ametropic. The genetic correlation between eye size and refractive error was calculated using linkage disequilibrium score regression for approximately 1 million genetic variants. Results The GWAS for corneal curvature in emmetropes identified 32 independent genetic variants (P < 5.0e-08). A polygenic score created using these 32 genetic markers explained 3.5% (P < 0.001) and 2.0% (P = 0.001) of the variance in corneal curvature and axial length, respectively, in the independent sample of emmetropic individuals but was not predictive of these traits in ametropic individuals. The genetic correlation between eye size and refractive error was close to zero (rg = 0.00; SE = 0.06; P = 0.95). Conclusions These results support the hypothesis that genetic variants regulating eye size in emmetropic eyes do not overlap with those conferring susceptibility to myopia. This suggests that distinct biological pathways regulate normal eye growth and myopia development.
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Affiliation(s)
- Denis Plotnikov
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.,Central Research Laboratory, Kazan State Medical University, Kazan, Russia
| | - Jiangtian Cui
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Rosie Clark
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Juho Wedenoja
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Department of Public Health, University of Helsinki, Helsinki, Finland
| | - Olavi Pärssinen
- Gerontology Research Center and Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - J Willem L Tideman
- Department of Ophthalmology, Erasmus Medical Centre, Rotterdam, The Netherlands.,Department of Epidemiology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Jost B Jonas
- Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Yaxing Wang
- Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Igor Rudan
- Centre for Global Health and WHO Collaborating Centre, University of Edinburgh, United Kingdom
| | - Terri L Young
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, University of Western Australia, Lions Eye Institute, Perth, Australia
| | - Louise Terry
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Cathy Williams
- Centre for Academic Child Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Jeremy A Guggenheim
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
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14
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Haug P, Koller S, Maggi J, Lang E, Feil S, Wlodarczyk A, Bähr L, Steindl K, Rohrbach M, Gerth-Kahlert C, Berger W. Whole Exome Sequencing in Coloboma/Microphthalmia: Identification of Novel and Recurrent Variants in Seven Genes. Genes (Basel) 2021; 12:65. [PMID: 33418956 PMCID: PMC7825129 DOI: 10.3390/genes12010065] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/25/2020] [Accepted: 12/31/2020] [Indexed: 12/16/2022] Open
Abstract
Coloboma and microphthalmia (C/M) are related congenital eye malformations, which can cause significant visual impairment. Molecular diagnosis is challenging as the genes associated to date with C/M account for only a small percentage of cases. Overall, the genetic cause remains unknown in up to 80% of patients. High throughput DNA sequencing technologies, including whole-exome sequencing (WES), are therefore a useful and efficient tool for genetic screening and identification of new mutations and novel genes in C/M. In this study, we analyzed the DNA of 19 patients with C/M from 15 unrelated families using singleton WES and data analysis for 307 genes of interest. We identified seven novel and one recurrent potentially disease-causing variants in CRIM1, CHD7, FAT1, PTCH1, PUF60, BRPF1, and TGFB2 in 47% of our families, three of which occurred de novo. The detection rate in patients with ocular and extraocular manifestations (67%) was higher than in patients with an isolated ocular phenotype (46%). Our study highlights the significant genetic heterogeneity in C/M cohorts and emphasizes the diagnostic power of WES for the screening of patients and families with C/M.
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Affiliation(s)
- Patricia Haug
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Jordi Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Elena Lang
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
- Department of Ophthalmology, University Hospital and University of Zurich, 8091 Zurich, Switzerland;
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Agnès Wlodarczyk
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Luzy Bähr
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, 8952 Schlieren, Switzerland;
| | - Marianne Rohrbach
- Division of Metabolism and Children’s Research Centre, University Children’s Hospital Zurich, 8032 Zurich, Switzerland;
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital and University of Zurich, 8091 Zurich, Switzerland;
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
- Neuroscience Center Zurich (ZNZ), University and ETH Zurich, 8006 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8006 Zurich, Switzerland
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15
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Islam F, Htun S, Lai LW, Krall M, Poranki M, Martin PM, Sobreira N, Wohler ES, Yu J, Moore AT, Slavotinek AM. Exome sequencing in patients with microphthalmia, anophthalmia, and coloboma (MAC) from a consanguineous population. Clin Genet 2020; 98:499-506. [PMID: 32799327 DOI: 10.1111/cge.13830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/08/2020] [Accepted: 08/10/2020] [Indexed: 12/13/2022]
Abstract
Next-generation sequencing strategies have resulted in mutation detection rates of 21% to 61% in small cohorts of patients with microphthalmia, anophthalmia and coloboma (MAC), but despite progress in identifying novel causative genes, many patients remain without a genetic diagnosis. We studied a cohort of 19 patients with MAC who were ascertained from a population with high rates of consanguinity. Using single nucleotide polymorphism (SNP) arrays and whole exome sequencing (WES), we identified one pathogenic variant in TENM3 in a patient with cataracts in addition to MAC. We also detected novel variants of unknown significance in genes that have previously been associated with MAC, including KIF26B, MICU1 and CDON, and identified variants in candidate genes for MAC from the Wnt signaling pathway, comprising LRP6, WNT2B and IQGAP1, but our findings do not prove causality. Plausible variants were not found for many of the cases, indicating that our current understanding of the pathogenesis of MAC, a highly heterogeneous group of ocular defects, remains incomplete.
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Affiliation(s)
- Farrah Islam
- Department of Ophthalmology, Al-Shifa Eye Trust Hospital, Rawalpindi, Pakistan
| | - Stephanie Htun
- Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
| | - Li-Wen Lai
- Department of Pathology, University of Arizona, Tucson, Arizona, USA
| | - Max Krall
- Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
| | - Menitha Poranki
- Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
| | - Pierre-Marie Martin
- Institute of Human Genetics, University of California San Francisco, San Francisco, California, USA
| | - Nara Sobreira
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Elizabeth S Wohler
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jingwei Yu
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, USA
| | - Anthony T Moore
- Dept. Ophthalmology, University of California San Francisco, San Francisco, California, USA
| | - Anne M Slavotinek
- Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, California, USA
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16
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Revealing hidden genetic diagnoses in the ocular anterior segment disorders. Genet Med 2020; 22:1623-1632. [PMID: 32499604 PMCID: PMC7521990 DOI: 10.1038/s41436-020-0854-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/27/2022] Open
Abstract
Purpose Ocular anterior segment disorders (ASDs) are clinically and genetically heterogeneous, and genetic diagnosis often remains elusive. In this study, we demonstrate the value of a combined analysis protocol using phenotypic, genomic, and pedigree structure data to achieve a genetic conclusion. Methods We utilized a combination of chromosome microarray, exome sequencing, and genome sequencing with structural variant and trio analysis to investigate a cohort of 41 predominantly sporadic cases. Results We identified likely causative variants in 54% (22/41) of cases, including 51% (19/37) of sporadic cases and 75% (3/4) of cases initially referred as familial ASD. Two-thirds of sporadic cases were found to have heterozygous variants, which in most cases were de novo. Approximately one-third (7/22) of genetic diagnoses were found in rarely reported or recently identified ASD genes including PXDN, GJA8, COL4A1, ITPR1, CPAMD8, as well as the new phenotypic association of Axenfeld–Rieger anomaly with a homozygous ADAMTS17 variant. The remainder of the variants were in key ASD genes including FOXC1, PITX2, CYP1B1, FOXE3, and PAX6. Conclusions We demonstrate the benefit of detailed phenotypic, genomic, variant, and segregation analysis to uncover some of the previously “hidden” heritable answers in several rarely reported and newly identified ocular ASD-related disease genes.
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17
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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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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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