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BACKGROUND: Uveal coloboma, a developmental eye defect, is caused by failed development of the optic fissure, a ventral structure in the optic stalk and cup where axons exit the eye and vasculature enters. The Hedgehog (Hh) signaling pathway regulates optic fissure development: loss-of-function mutations in the Hh receptor ptch2 produce overactive Hh signaling and can result in coloboma. We previously proposed a model where overactive Hh signaling disrupts optic fissure formation by upregulating transcriptional targets acting both cell- and non-cell-autonomously. Here, we examine the Netrin family of secreted ligands as candidate Hh target genes. RESULTS: We find multiple Netrin ligands upregulated in the zebrafish ptch2 mutant during optic fissure development. Using a gain-of-function approach to overexpress Netrin in a spatiotemporally specific manner, we find that netrin1a or netrin1b overexpression is sufficient to cause coloboma and disrupt wild-type optic fissure formation. We used loss-of-function alleles, CRISPR/Cas9 mutagenesis, and morpholino knockdown to test if loss of Netrin can rescue coloboma in the ptch2 mutant: loss of netrin genes does not rescue the ptch2 mutant phenotype. CONCLUSION: These results suggest that Netrin is sufficient but not required to disrupt optic fissure formation downstream of overactive Hh signaling in the ptch2 mutant.
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CHARGE syndrome is a rare multi-system condition associated with CHD7 variants. However, ocular manifestations and particularly ophthalmic genotype-phenotype associations, are not well-studied. This study evaluated ocular manifestations and genotype-phenotype associations in pediatric patients with CHARGE syndrome. A retrospective chart review included pediatric patients under 20 years-old with clinical diagnosis of CHARGE syndrome and documented ophthalmic examination. Demographics, genetic testing, and ocular findings were collected. Comprehensive literature review enhanced the genotype-phenotype analysis. Forty-two patients (20 male) underwent eye examination at an average age of 9.45 ± 6.52 years-old. Thirty-nine (93%) had ophthalmic manifestations in at least one eye. Optic nerve/chorioretinal colobomas were most common (38 patients), followed by microphthalmia (13), cataract (6), and iris colobomas (4). Extraocular findings included strabismus (32 patients), nasolacrimal duct obstructions (11, 5 with punctal agenesis), and cranial nerve VII palsy (10). Genotype-phenotype analyses (27 patients) showed variability in ocular phenotypes without association to location or variant types. Splicing (10 patients) and frameshift (10) variants were most prevalent. Patients with CHARGE syndrome may present with a myriad of ophthalmic manifestations. There is limited data regarding genotype-phenotype correlations and additional studies are needed.
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Síndrome CHARGE , Estudos de Associação Genética , Fenótipo , Humanos , Síndrome CHARGE/genética , Síndrome CHARGE/patologia , Síndrome CHARGE/diagnóstico , Masculino , Criança , Feminino , Pré-Escolar , Adolescente , Coloboma/genética , Coloboma/patologia , Lactente , Genótipo , Mutação/genética , Estudos Retrospectivos , Proteínas de Ligação a DNA/genética , DNA Helicases/genética , Catarata/genética , Catarata/patologia , Adulto JovemRESUMO
Renal ciliopathies are a common cause of kidney failure in children and adults, and this study reviewed their ocular associations. Genes affected in renal ciliopathies were identified from the Genomics England Panels. Ocular associations were identified from Medline and OMIM, and the genes additionally examined for expression in the human retina ( https://www.proteinatlas.org/humanproteome/tissue ) and for an ocular phenotype in mouse models ( http://www.informatics.jax.org/ ). Eighty-two of the 86 pediatric-onset renal ciliopathies (95%) have an ocular phenotype, including inherited retinal degeneration, oculomotor disorders, and coloboma. Diseases associated with pathogenic variants in ANK6, MAPKBP1, NEK8, and TCTN1 have no reported ocular manifestations, as well as low retinal expression and no ocular features in mouse models. Ocular abnormalities are not associated with the most common adult-onset "cystic" kidney diseases, namely, autosomal dominant (AD) polycystic kidney disease and the AD tubulointerstitial kidney diseases (ADTKD). However, other kidney syndromes with cysts have ocular features including papillorenal syndrome (optic disc dysplasia), Hereditary Angiopathy Nephropathy, Aneurysms and muscle Cramps (HANAC) (tortuous retinal vessels), tuberous sclerosis (retinal hamartomas), von Hippel-Lindau syndrome (retinal hemangiomas), and Alport syndrome (lenticonus, fleck retinopathy). Ocular abnormalities are associated with many pediatric-onset renal ciliopathies but are uncommon in adult-onset cystic kidney disease. However the demonstration of ocular manifestations may be helpful diagnostically and the features may require monitoring or treatment.
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Ciliopatias , Doenças Renais Císticas , Nefrite Hereditária , Doenças Retinianas , Adulto , Criança , Animais , Camundongos , Humanos , Rim/patologia , Doenças Retinianas/genética , Nefrite Hereditária/genética , Retina , Doenças Renais Císticas/complicações , Ciliopatias/complicaçõesRESUMO
Renal coloboma syndrome (RCS) and dominant optic atrophy are mainly caused by heterozygous mutations in PAX2 and OPA1, respectively. We describe a patient with digenic mutations in PAX2 and OPA1. A female infant was born without perinatal abnormalities. Magnetic resonance imaging at 4 months of age showed bilateral microphthalmia and optic nerve hypoplasia. Appropriate body size was present at 2 years of age, and mental development was favorable. Color fundus photography revealed severe retinal atrophy in both eyes. Electroretinography showed slight responses in the right eye, but no responses in the left eye, suggesting a high risk of blindness. Urinalysis results were normal, creatinine-based estimated glomerular filtration rate was 63.5 mL/min/1.73 m2, and ultrasonography showed bilateral hypoplastic kidneys. Whole exome sequencing revealed de novo frameshift mutations in PAX2 and OPA1. Both variants were classified as pathogenic (PVS1, PS2, PM2) based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). Genetic testing for ocular diseases should be considered for patients with suspected RCS and a high risk of total blindness.
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Coloboma , GTP Fosfo-Hidrolases , Fator de Transcrição PAX2 , Refluxo Vesicoureteral , Humanos , Feminino , Fator de Transcrição PAX2/genética , GTP Fosfo-Hidrolases/genética , Coloboma/genética , Coloboma/diagnóstico , Refluxo Vesicoureteral/genética , Refluxo Vesicoureteral/diagnóstico , Atrofia Óptica Autossômica Dominante/genética , Atrofia Óptica Autossômica Dominante/diagnóstico , Anormalidades Urogenitais/genética , Anormalidades Urogenitais/diagnóstico , Anormalidades Urogenitais/complicações , Mutação da Fase de Leitura , Sequenciamento do Exoma , Lactente , Pré-Escolar , Mutação , Insuficiência RenalRESUMO
Congenital anomalies of the kidney and urinary tract (CAKUT) are among the most common birth defects worldwide and a major cause of kidney failure in children. Extra-renal manifestations are also common. This study reviewed diseases associated with the Genomics England CAKUT-associated gene panel for ocular anomalies. In addition, each gene was examined for expression in the human retina and an ocular phenotype in mouse models using the Human Protein Atlas and Mouse Genome Informatics databases, respectively. Thirty-four (54%) of the 63 CAKUT-associated genes (55 'green' and 8 'amber') had a reported ocular phenotype. Five of the 6 most common CAKUT-associated genes (PAX2, EYA1, SALL1, GATA3, PBX1) that represent 30% of all diagnoses had ocular features. The ocular abnormalities found with most CAKUT-associated genes and with five of the six commonest were coloboma, microphthalmia, optic disc anomalies, refraction errors (astigmatism, myopia, and hypermetropia), and cataract. Seven of the CAKUT-associated genes studied (11%) had no reported ocular features but were expressed in the human retina or had an ocular phenotype in a mouse model, which suggested further possibly-unrecognised abnormalities. About one third of CAKUT-associated genes (18, 29%) had no ocular associations and were not expressed in the retina, and the corresponding mouse models had no ocular phenotype. Ocular abnormalities in individuals with CAKUT suggest a genetic basis for the disease and sometimes indicate the affected gene. Individuals with CAKUT often have ocular abnormalities and may require an ophthalmic review, monitoring, and treatment to preserve vision.
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Sistema Urinário , Anormalidades Urogenitais , Refluxo Vesicoureteral , Criança , Camundongos , Animais , Humanos , Rim/metabolismo , Sistema Urinário/anormalidades , Refluxo Vesicoureteral/genética , Refluxo Vesicoureteral/diagnóstico , Anormalidades Urogenitais/genética , Anormalidades Urogenitais/diagnósticoRESUMO
BACKGROUND: RERE is a highly conserved transcriptional co-regulator that is associated with a human neurodevelopmental disorder with or without anomalies of the brain, eye, or heart (NEDBEH, OMIM: 616975). RESULTS: We show that the zebrafish rerea mutant (babyface) robustly recapitulates optic fissure closure defects resulting from loss of RERE function, as observed in humans. These defects result from expansion of proximal retinal optic stalk (OS) and reduced expression of some of the ventral retinal fate genes due to deregulated protein signaling. Using zebrafish and cell-based assays, we determined that NEDBEH-associated human RERE variants function as hypomorphs in their ability to repress shh signaling and some exhibit abnormal nuclear localization. Inhibiting shh signaling by the protein inhibitor HPI-1 rescues coloboma, confirming our observation that coloboma in rerea mutants is indeed due to deregulation of shh signaling. CONCLUSIONS: Zebrafish rerea mutants exhibit OS and optic fissure closure defects. The optic fissure closure defect was rescued by an shh signaling inhibitor, suggesting that this defect could arise due to deregulated shh signaling.
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Coloboma , Proteínas de Peixe-Zebra , Peixe-Zebra , Animais , Humanos , Proteínas de Transporte/metabolismo , Coloboma/genética , Coloboma/metabolismo , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Retina/metabolismo , Transdução de Sinais/fisiologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
BACKGROUND: Pathogenic variants in human MAB21L2 result in microphthalmia, anophthalmia, and coloboma. The exact molecular function of MAB21L2 is currently unknown. We conducted a series of yeast two-hybrid (Y2H) experiments to determine protein interactomes of normal human and zebrafish MAB21L2/mab21l2 as well as human disease-associated variant MAB21L2-p.(Arg51Gly) using human adult retina and zebrafish embryo libraries. RESULTS: These screens identified klhl31, tnpo1, TNPO2/tnpo2, KLC2/klc2, and SPTBN1/sptbn1 as co-factors of MAB21L2/mab21l2. Several factors, including hspa8 and hspa5, were found to interact with MAB21L2-p.Arg51Gly but not wild-type MAB21L2/mab21l2 in Y2H screens. Further analyses via 1-by-1 Y2H assays, co-immunoprecipitation, and mass spectrometry revealed that both normal and variant MAB21L2 interact with HSPA5 and HSPA8. In situ hybridization detected co-expression of hspa5 and hspa8 with mab21l2 during eye development in zebrafish. Examination of zebrafish mutant hspa8hi138Tg identified reduced hspa8 expression associated with severe ocular developmental defects, including small eye, coloboma, and anterior segment dysgenesis. To investigate the effects of hspa8 deficiency on the mab21l2Arg51_Phe52del allele, corresponding zebrafish double mutants were generated and found to be more severely affected than single mutant lines. CONCLUSION: This study identifies heat shock proteins as interacting partners of MAB21L2/mab21l2 and suggests a role for this interaction in vertebrate eye development.
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Coloboma , Anormalidades do Olho , Adulto , Animais , Humanos , Coloboma/patologia , Olho , Proteínas do Olho/metabolismo , Proteínas de Choque Térmico HSC70/genética , Peptídeos e Proteínas de Sinalização Intracelular , Retina/metabolismo , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genéticaRESUMO
PURPOSE: Cataract surgery in microphthalmic eyes is challenging due to anatomical restraints, hard bulky nucleus. This series aims to evaluate the safety and efficacy of couching of intraocular lens in irido-fundal coloboma with microphthalmos. SETTING: Tertiary care centre in South India. DESIGN: Retrospective non-comparative study in eyes with irido-fundal coloboma, corneal diameter < 7 mm and brown cataract. Visual acuity less than 6/60 in other eye. METHODS: Anterior chamber entry made, zonules broken and lens dislocated into the vitreous cavity in a controlled manner. Baseline Clinico-demographic details, corrected distance visual acuity (CDVA), Intra-ocular pressure (IOP), corneal diameter, axial length, lens status and post-surgery CDVA, IOP and complications recorded and followed up for atleast 6 months. RESULTS: Fifteen eyes of 15 subjects were evaluated with a mean age 49.4 ± 10.9 years. At baseline, mean IOP 14.5 ± 3.8 mmHg, mean axial length 19.3 ± 0.5 mm, mean corneal diameter was 6.5 ± 0.34 mm and CDVA 2 logMAR which improved to 1.5 logMAR at 3 months (p value 0.002). Transient spike in IOP in 33.3% subjects was medically managed with no significant difference in IOP (p > 0.05) at baseline (14.5 ± 3.8 mmHg), 3 months post-surgery (16 ± 2.8 mmHg) and 6 months post-surgery (14.9 ± 2.5 mmHg). One patient underwent re-couching. No other major complications were noted. CONCLUSION: Couching of cataractous lens is an effective and safe method in microphthalmic eyes with irido-fundal coloboma as last resort procedure, where no other surgical procedure may work. It provides an ambulatory gain of visual acuity in previously non-ambulatory subjects. Corneal measurements help in determining the subset of patients where couching offers viable option.
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Catarata , Coloboma , Microftalmia , Acuidade Visual , Humanos , Estudos Retrospectivos , Feminino , Coloboma/diagnóstico , Coloboma/complicações , Coloboma/cirurgia , Masculino , Microftalmia/complicações , Microftalmia/diagnóstico , Microftalmia/cirurgia , Catarata/complicações , Catarata/congênito , Catarata/diagnóstico , Pessoa de Meia-Idade , Adulto , Iris/cirurgia , Iris/anormalidades , Implante de Lente Intraocular/métodos , Extração de Catarata/métodos , Cristalino/anormalidades , Cristalino/cirurgia , SeguimentosRESUMO
This study investigates a unique and complex eye phenotype characterized by minimal iris defects, foveal hypoplasia, optic nerve coloboma, and severe posterior segment damage. Through genetic analysis and bioinformatic tools, a specific nonsynonymous substitution, p.(Asn114Ser), within the PAX6 gene's paired domain is identified. Although this substitution is not in direct contact with DNA, its predicted stabilizing effect on the protein structure challenges the traditional understanding of PAX6 mutations, suggesting a gain-of-function mechanism. Contrary to classical loss-of-function effects, this gain-of-function hypothesis aligns with research demonstrating PAX6's dosage sensitivity. Gain-of-function mutations, though less common, can lead to diverse phenotypes distinct from aniridia. Our findings emphasize PAX6's multifaceted influence on ocular phenotypes and the importance of genetic variations. We contribute a new perspective on PAX6 mutations by suggesting a potential gain-of-function mechanism and showcasing the complexities of ocular development. This study sheds light on the intricate interplay of the genetic alterations and regulatory mechanisms underlying complex eye phenotypes. Further research, validation, and collaboration are crucial to unravel the nuanced interactions shaping ocular health and development.
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Ocular coloboma is a congenital eye malformation, resulting from a failure in optic fissure closure (OFC) and causing visual impairment. There has been little study of the epithelial fusion process underlying closure in the human embryo and coloboma aetiology remains poorly understood. We performed RNAseq of cell populations isolated using laser capture microdissection to identify novel human OFC signature genes and probe the expression profile of known coloboma genes, along with a comparative murine analysis. Gene set enrichment patterns showed conservation between species. Expression of genes involved in epithelial-to-mesenchymal transition was transiently enriched in the human fissure margins during OFC at days 41-44. Electron microscopy and histological analyses showed that cells transiently delaminate at the point of closure, and produce cytoplasmic protrusions, before rearranging to form two continuous epithelial layers. Apoptosis was not observed in the human fissure margins. These analyses support a model of human OFC in which epithelial cells at the fissure margins undergo a transient epithelial-to-mesenchymal-like transition, facilitating cell rearrangement to form a complete optic cup.
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Coloboma/genética , Anormalidades do Olho/genética , Olho/ultraestrutura , Disco Óptico/ultraestrutura , Animais , Apoptose/genética , Sequência de Bases/genética , Coloboma/patologia , Transição Epitelial-Mesenquimal/genética , Olho/patologia , Anormalidades do Olho/patologia , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Microdissecção e Captura a Laser , Camundongos , Microscopia EletrônicaRESUMO
A crucial step in eye development is the closure of the choroid fissure (CF), a transient structure in the ventral optic cup through which vasculature enters the eye and ganglion cell axons exit. Although many factors have been identified that function during CF closure, the molecular and cellular mechanisms mediating this process remain poorly understood. Failure of CF closure results in colobomas. Recently, MITF was shown to be mutated in a subset of individuals with colobomas, but how MITF functions during CF closure is unknown. To address this issue, zebrafish with mutations in mitfa and tfec, two members of the Mitf family of transcription factors, were analyzed and their functions during CF closure determined. mitfa;tfec mutants possess severe colobomas and our data demonstrate that Mitf activity is required within cranial neural crest cells (cNCCs) during CF closure. In the absence of Mitf function, cNCC migration and localization in the optic cup are perturbed. These data shed light on the cellular mechanisms underlying colobomas in individuals with MITF mutations and identify a novel role for Mitf function in cNCCs during CF closure.
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Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Corioide/citologia , Corioide/embriologia , Fator de Transcrição Associado à Microftalmia/metabolismo , Crista Neural/citologia , Crânio/citologia , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Animais , Coloboma/patologia , Embrião de Mamíferos/citologia , Humanos , Mutação/genética , Crista Neural/metabolismo , Epitélio Pigmentado da Retina/embriologiaRESUMO
Four members of a three-generation Czech family with early-onset chorioretinal dystrophy were shown to be heterozygous carriers of the n.37C>T in MIR204. The identification of this previously reported pathogenic variant confirms the existence of a distinct clinical entity caused by a sequence change in MIR204. Chorioretinal dystrophy was variably associated with iris coloboma, congenital glaucoma, and premature cataracts extending the phenotypic range of the condition. In silico analysis of the n.37C>T variant revealed 713 novel targets. Additionally, four family members were shown to be affected by albinism resulting from biallelic pathogenic OCA2 variants. Haplotype analysis excluded relatedness with the original family reported to harbour the n.37C>T variant in MIR204. Identification of a second independent family confirms the existence of a distinct MIR204-associated clinical entity and suggests that the phenotype may also involve congenital glaucoma.
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Catarata , Coloboma , Glaucoma , MicroRNAs , Humanos , Coloboma/complicações , Coloboma/genética , Mutação , Linhagem , Iris/anormalidades , Glaucoma/complicações , Glaucoma/genética , Catarata/genética , Catarata/congênitoRESUMO
We aim to assess if genotype-phenotype correlations are present within ocular manifestations of Kabuki syndrome (KS) among a large multicenter cohort. We conducted a retrospective, medical record review including clinical history and comprehensive ophthalmological examinations of a total of 47 individuals with molecularly confirmed KS and ocular manifestations at Boston Children's Hospital and Cincinnati Children's Hospital Medical Center. We assessed information regarding ocular structural, functional, and adnexal elements as well as pertinent associated phenotypic features associated with KS. For both type 1 KS (KS1) and type 2 KS (KS2), we observed more severe eye pathology in nonsense variants towards the C-terminus of each gene, KMT2D and KDM6A, respectively. Furthermore, frameshift variants appeared to be not associated with structural ocular elements. Between both types of KS, ocular structural elements were more frequently identified in KS1 compared with KS2, which only involved the optic disc in our cohort. These results reinforce the need for a comprehensive ophthalmologic exam upon diagnosis of KS and regular follow-up exams. The specific genotype may allow risk stratification of the severity of the ophthalmologic manifestation. However, additional studies involving larger cohorts are needed to replicate our observations and conduct powered analyses to more formally risk-stratify based on genotype, highlighting the importance of multicenter collaborations in rare disease research.
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Anormalidades Múltiplas , Doenças Vestibulares , Humanos , Estudos Retrospectivos , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Doenças Vestibulares/diagnóstico , Doenças Vestibulares/genética , Doenças Vestibulares/complicações , Fenótipo , Genótipo , Histona Desmetilases/genética , MutaçãoRESUMO
C-mannosylation is a modification of tryptophan residues with a single mannose and can affect protein folding, secretion, and/or function. To date, only a few proteins have been demonstrated to be C-mannosylated, and studies that globally assess protein C-mannosylation are scarce. To interrogate the C-mannosylome of human induced pluripotent stem cells, we compared the secretomes of CRISPR-Cas9 mutants lacking either the C-mannosyltransferase DPY19L1 or DPY19L3 to WT human induced pluripotent stem cells using MS-based quantitative proteomics. The secretion of numerous proteins was reduced in these mutants, including that of A Disintegrin And Metalloproteinase with ThromboSpondin Motifs 16 (ADAMTS16), an extracellular protease that was previously reported to be essential for optic fissure fusion in zebrafish eye development. To test the functional relevance of this observation, we targeted dpy19l1 or dpy19l3 in embryos of the Japanese rice fish medaka (Oryzias latipes) by CRISPR-Cas9. We observed that targeting of dpy19l3 partially caused defects in optic fissure fusion, called coloboma. We further showed in a cellular model that DPY19L1 and DPY19L3 mediate C-mannosylation of a recombinantly expressed thrombospondin type 1 repeat of ADAMTS16 and thereby support its secretion. Taken together, our findings imply that DPY19L3-mediated C-mannosylation is involved in eye development by assisting secretion of the extracellular protease ADAMTS16.
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Proteínas ADAMTS/metabolismo , Olho/crescimento & desenvolvimento , Manosiltransferases/metabolismo , Animais , Linhagem Celular , Cricetulus , Edição de Genes , Técnicas de Silenciamento de Genes , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Manose , Manosiltransferases/genética , OryziasRESUMO
OBJECTIVE: PURPOSE: To observe the safety and effect of the C-pupilloplasty for the treatment of iris coloboma and traumatic iris defects. METHODS: A total of 21 cases (21 eyes) with iris coloboma or traumatic iris defects who underwent C-pupilloplasty (a single-pass three-throw technique) from Feb. 2016 to Mar. 2020 were analyzed retrospectively. Uncorrected visual acuity, refraction, corneal topographic keratometry and endothelial cell density were examined. RESULTS: All the patients were successfully treated, and a central and round pupil was restored. The mean follow-up duration was 8.76 ± 3.58 months (ranging from 2 to 14 months). All patients had round or round-like pupils with a diameter less than or equal to 3 mm after the C-pupilloplasty. Very slightly endothelial loss, negligible symptoms such as glare, distortion, dizziness and photophobia were observed. CONCLUSION: We introduced a new technique of pupilloplasty (C-pupilloplasty) which could be a more straight forward and more effective treatment for iris coloboma and traumatic iris defect.
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Coloboma , Doenças da Íris , Humanos , Coloboma/cirurgia , Estudos Retrospectivos , Iris/cirurgia , Pupila , Procedimentos Cirúrgicos Oftalmológicos/métodos , Doenças da Íris/cirurgiaRESUMO
Acquired lens colobomas secondary to ocular surgeries are scarcely described in the literature. We describe two cases of acquired lens coloboma in two infants with glaucoma who underwent ocular surgery. The coloboma in the first case was likely because of direct trauma to the lens zonules during an optical iridectomy with a vitrectomy cutter, resulting in localized loss of zonules and consequently localized lens coloboma. The coloboma in the second case was noticed during examination under anesthesia after scleral buckling and cryopexy for retinal detachment. The cause for coloboma development in this case could be disruption of the lens zonules because of stretching of the globe after scleral buckle surgery or because of injury to zonules during scleral buckling and the cryopexy procedure.
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Coloboma , Descolamento Retiniano , Humanos , Coloboma/cirurgia , Coloboma/complicações , Recurvamento da Esclera/efeitos adversos , Recurvamento da Esclera/métodos , Descolamento Retiniano/cirurgia , Descolamento Retiniano/complicações , Corioide , Vitrectomia/efeitos adversos , Estudos RetrospectivosRESUMO
PURPOSE: To report a case of feline bilateral corneal dermoids, associated with unilateral iris coloboma and bilateral choroido-scleral colobomas in the same dorsolateral position, to describe retinographic and optical coherence tomography (OCT) characteristics, surgical outcome, and follow-up. ANIMAL STUDIED: A 9-month-old domestic shorthaired cat in which a full ophthalmoscopic examination was performed for evaluation of dermoids resulting in a diagnosis of associated iris coloboma in one eye and posterior colobomas in both eyes. PROCEDURES: Retinographies and OCT were performed under anesthesia to characterize the lesions of both fundi and allow surgical excision of the corneal dermoids. RESULTS: Ophthalmoscopy and retinographies revealed oval lesions in the dorsolateral fundi of both eyes. The lesions precisely mirrored their respective dermoids' (10-11 h OD and 1-2 h OS) clock positions, lacked a tapetum lucidum and choroidal vessels, and featured thin retinal vessels plunging to a posterior plane of the fundus. OCT crossline scans demonstrated preservation of retinal thickness and morphological layering in the fundic colobomas leading to the conclusion that the colobomas were purely choroido-scleral. The outcome of the surgical excision of the dermoids was satisfactory without hair recurrence and with acceptable corneal clarity making it possible to visualize the unilateral associated iris coloboma. Follow-ups did not reveal any fundic evolution nor retinal detachment. CONCLUSIONS: Retinographies and OCT made possible the characterization of choroido-scleral colobomas associated with corneal dermoids in this first reported case in a cat. We hypothesize that the recently described superior ocular sulcus might be the embryological link between these anomalies.
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Doenças do Gato , Coloboma , Cisto Dermoide , Gatos , Animais , Coloboma/diagnóstico por imagem , Coloboma/cirurgia , Coloboma/veterinária , Tomografia de Coerência Óptica/veterinária , Tomografia de Coerência Óptica/métodos , Cisto Dermoide/veterinária , Seguimentos , Resultado do Tratamento , Doenças do Gato/diagnóstico por imagem , Doenças do Gato/cirurgiaRESUMO
BACKGROUND: Pax2 is required for optic fissure development in many organisms, including humans and zebrafish. Zebrafish loss-of-function mutations in pax2a display coloboma, yet the etiology of the morphogenetic defects is unclear. Further, pax2 is duplicated in zebrafish, and a role for pax2b in optic fissure development has not been examined. RESULTS: Using a combination of imaging and molecular genetics, we interrogated a potential role for pax2b and examined how loss of pax2 affects optic fissure development. Although optic fissure formation appears normal in pax2 mutants, an endothelial-specific subset of periocular mesenchyme (POM) fails to initially localize within the optic fissure, yet both neural crest and endothelial-derived POM ectopically accumulate at later stages in pax2a and pax2a; pax2b mutants. Apoptosis is not up-regulated within the optic fissure in pax2 mutants, yet cell death is increased in tissues outside of the optic fissure, and when apoptosis is inhibited, coloboma is partially rescued. In contrast to pax2a, loss of pax2b does not appear to affect optic fissure morphogenesis. CONCLUSIONS: Our results suggest that pax2a, but not pax2b, supports cell survival outside of the optic fissure and POM abundance within it to facilitate optic fissure closure.
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Proteínas de Peixe-Zebra , Peixe-Zebra , Animais , Sobrevivência Celular/genética , Olho , Mesoderma/metabolismo , Morfogênese/genética , Fator de Transcrição PAX2/genética , Fator de Transcrição PAX2/metabolismo , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
Large congenital lid colobomas are traditionally repaired using 1- or 2-step vascularized flap-graft combinations. However, visual axis occlusion for weeks is a severe problem in small children and recent reports suggest that the flap pedicle does not contribute to blood perfusion. A "one-step" substitute for large lid defects has recently been reported in animals and humans, demonstrating the viability of a bilamellar autograft alone. We present an alternative "one-step" reconstructive approach in a 6-month-old infant who had a centrally-located large upper eyelid defect resulting from a congenital coloboma. The free full-thickness bilamellar autograft was harvested from the contralateral upper eyelid. The follow-up time was 48 months. Cosmetic and functional results were good, the bilamellar graft survived, and there was no graft ischemia, necrosis, or rejection. The boy developed madarosis, lid notching, and mild contour irregularity but needed no reoperation since the parent was satisfied with the surgical result. A free bilamellar eyelid autograft seems to be an outstanding alternative to both "conventional 2-step" and "modern 1-step" options for the reconstruction of large colobomatous eyelid openings, especially in young infants who cannot tolerate visual axis blockage. It is an easy, practical, fast, and effective technique that also saves cost in health care.
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The nasopalpebral lipoma-coloboma syndrome was described for the first time in 1982. It is an autosomal dominant syndrome with complete penetrance and is characterized by features like congenital symmetric upper eyelid and nasopalpebral lipomas, bilateral symmetric upper and lower eyelid colobomas, broad forehead, widow's peak, abnormal eyebrow pattern, telecanthus, broad nasal bridge, maxillary hypoplasia, and ophthalmological abnormalities. We report a case of a milder variant of the nasopalpebral lipoma-coloboma syndrome that we have termed "nasopalpebral lipoma sine coloboma syndrome." Such a milder variant is not reported hitherto in the literature. We also describe the surgical correction of the deformity in a case that presented in adulthood, with a satisfactory and pleasing aesthetic outcome.