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Journal of Medical Genetics Apr 2023Axenfeld-Rieger syndrome (ARS) is characterised by typical anterior segment anomalies, with or without systemic features. The discovery of causative genes identified ARS...
BACKGROUND
Axenfeld-Rieger syndrome (ARS) is characterised by typical anterior segment anomalies, with or without systemic features. The discovery of causative genes identified ARS subtypes with distinct phenotypes, but our understanding is incomplete, complicated by the rarity of the condition.
METHODS
Genetic and phenotypic characterisation of the largest reported ARS cohort through comprehensive genetic and clinical data analyses.
RESULTS
128 individuals with causative variants in or , including 81 new cases, were investigated. Ocular anomalies showed significant overlap but with broader variability and earlier onset of glaucoma for -related ARS. Systemic anomalies were seen in all individuals with -related ARS and the majority of those with -related ARS. -related ARS demonstrated typical umbilical anomalies and dental microdontia/hypodontia/oligodontia, along with a novel high rate of Meckel diverticulum. -related ARS exhibited characteristic hearing loss and congenital heart defects as well as previously unrecognised phenotypes of dental enamel hypoplasia and/or crowding, a range of skeletal and joint anomalies, hypotonia/early delay and feeding disorders with structural oesophageal anomalies in some. Brain imaging revealed highly penetrant white matter hyperintensities, colpocephaly/ventriculomegaly and frequent arachnoid cysts. The expanded phenotype of -related ARS identified here was found to fully overlap features of De Hauwere syndrome. The results were used to generate gene-specific management plans for the two types of ARS.
CONCLUSION
Since clinical features of ARS vary significantly based on the affected gene, it is critical that families are provided with a gene-specific diagnosis, -related ARS or -related ARS. De Hauwere syndrome is proposed to be a FOXC1opathy.
Topics: Humans; Homeodomain Proteins; Transcription Factors; Anterior Eye Segment; Eye Abnormalities; Forkhead Transcription Factors; Mutation
PubMed: 35882526
DOI: 10.1136/jmg-2022-108646 -
Genetics in Medicine : Official Journal... Nov 2015Two proα1(IV) chains, encoded by COL4A1, form trimers that contain, in addition, a proα2(IV) chain encoded by COL4A2 and are the major component of the basement... (Meta-Analysis)
Meta-Analysis Review
Two proα1(IV) chains, encoded by COL4A1, form trimers that contain, in addition, a proα2(IV) chain encoded by COL4A2 and are the major component of the basement membrane in many tissues. Since 2005, COL4A1 mutations have been known as an autosomal dominant cause of hereditary porencephaly. COL4A1 and COL4A2 mutations have been reported with a broader spectrum of cerebrovascular, renal, ophthalmological, cardiac, and muscular abnormalities, indicated as "COL4A1 mutation-related disorders." Genetic counseling is challenging because of broad phenotypic variation and reduced penetrance. At the Erasmus University Medical Center, diagnostic DNA analysis of both COL4A1 and COL4A2 in 183 index patients was performed between 2005 and 2013. In total, 21 COL4A1 and 3 COL4A2 mutations were identified, mostly in children with porencephaly or other patterns of parenchymal hemorrhage, with a high de novo mutation rate of 40% (10/24). The observations in 13 novel families harboring either COL4A1 or COL4A2 mutations prompted us to review the clinical spectrum. We observed recognizable phenotypic patterns and propose a screening protocol at diagnosis. Our data underscore the importance of COL4A1 and COL4A2 mutations in cerebrovascular disease, also in sporadic patients. Follow-up data on symptomatic and asymptomatic mutation carriers are needed for prognosis and appropriate surveillance.
Topics: Alleles; Anterior Eye Segment; Brain; Cerebral Hemorrhage; Cohort Studies; Collagen Type IV; Eye Abnormalities; Eye Diseases, Hereditary; Family; Gene Order; Genetic Association Studies; Genetic Loci; Genotype; Humans; Leukomalacia, Periventricular; Magnetic Resonance Imaging; Mutation; Pedigree; Phenotype; Porencephaly
PubMed: 25719457
DOI: 10.1038/gim.2014.210 -
Human Molecular Genetics Aug 2017Glaucoma is the leading cause of irreversible blindness worldwide. Although most glaucoma patients are elderly, congenital glaucoma and glaucomas of childhood are also... (Review)
Review
Glaucoma is the leading cause of irreversible blindness worldwide. Although most glaucoma patients are elderly, congenital glaucoma and glaucomas of childhood are also important causes of visual disability. Primary congenital glaucoma (PCG) is isolated, non-syndromic glaucoma that occurs in the first three years of life and is a major cause of childhood blindness. Other early-onset glaucomas may arise secondary to developmental abnormalities, such as glaucomas that occur with aniridia or as part of Axenfeld-Rieger syndrome. Congenital and childhood glaucomas have strong genetic bases and disease-causing mutations have been discovered in several genes. Mutations in three genes (CYP1B1, LTBP2, TEK) have been reported in PCG patients. Axenfeld-Rieger syndrome is caused by mutations in PITX2 or FOXC1 and aniridia is caused by PAX6 mutations. This review discusses the roles of these genes in primary congenital glaucoma and glaucomas of childhood.
Topics: Aniridia; Anterior Eye Segment; Cytochrome P-450 CYP1B1; Eye Abnormalities; Eye Diseases, Hereditary; Eye Proteins; Forkhead Transcription Factors; Glaucoma; Homeodomain Proteins; Humans; Latent TGF-beta Binding Proteins; Mutation; PAX6 Transcription Factor; Transcription Factors; Homeobox Protein PITX2
PubMed: 28549150
DOI: 10.1093/hmg/ddx205 -
International Journal of Molecular... Sep 2021Axenfeld-Rieger syndrome (ARS) encompasses a group of developmental disorders that affect the anterior segment of the eye, as well as systemic developmental defects in... (Review)
Review
Axenfeld-Rieger syndrome (ARS) encompasses a group of developmental disorders that affect the anterior segment of the eye, as well as systemic developmental defects in some patients. Malformation of the ocular anterior segment often leads to secondary glaucoma, while some patients also present with cardiovascular malformations, craniofacial and dental abnormalities and additional periumbilical skin. Genes that encode two transcription factors, and , account for almost half of known cases, while the genetic lesions in the remaining cases remain unresolved. Given the genetic similarity between zebrafish and humans, as well as robust antisense inhibition and gene editing technologies available for use in these animals, loss of function zebrafish models for ARS have been created and shed light on the mechanism(s) whereby mutations in these two transcription factors cause such a wide array of developmental phenotypes. This review summarizes the published phenotypes in zebrafish and loss of function models and discusses possible mechanisms that may be used to target pharmaceutical development and therapeutic interventions.
Topics: Animals; Anterior Eye Segment; Eye Abnormalities; Eye Diseases, Hereditary; Forkhead Transcription Factors; Humans; Transcription Factors; Zebrafish; Zebrafish Proteins
PubMed: 34576164
DOI: 10.3390/ijms221810001 -
Heliyon Jul 2023Axenfeld-Rieger Syndrome (ARS) is comprised of a group of autosomal dominant disorders that are each characterized by anterior segment abnormalities of the eye.... (Review)
Review
Axenfeld-Rieger Syndrome (ARS) is comprised of a group of autosomal dominant disorders that are each characterized by anterior segment abnormalities of the eye. Mutations in the transcription factors or are the most well-studied genetic manifestations of this syndrome. Due to the rarity this syndrome, ARS-associated neurological manifestations have not been well characterized. The purpose of this systematic review is to characterize and describe ARS neurologic manifestations that affect the cerebral vasculature and their early and late sequelae. PRISMA guidelines were followed; studies meeting inclusion criteria were analyzed for study design, evidence level, number of patients, patient age, whether the patients were related, genotype, ocular findings, and nervous system findings, specifically neurostructural and neurovascular manifestations. 63 studies met inclusion criteria, 60 (95%) were case studies or case series. The gene was most commonly found, followed by , then . The most commonly described structural neurological findings were white matter abnormalities in 26 (41.3%) of studies, followed by Dandy-Walker Complex 12 (19%), and agenesis of the corpus callosum 11 (17%). Neurovascular findings were examined in 6 (9%) of studies, identifying stroke, cerebral small vessel disease (CSVD), tortuosity/dolichoectasia of arteries, among others, with no mention of moyamoya. This is the first systematic review investigating the genetic, neurological, and neurovascular associations with ARS. Structural neurological manifestations were common, yet often benign, perhaps limiting the utility of MRI screening. Neurovascular abnormalities, specifically stroke and CSVD, were identified in this population. Stroke risk was present in the presence and absence of cardiac comorbidities. These findings suggest a relationship between ARS and neurovascular findings; however, larger scale studies are necessary inform therapeutic decisions.
PubMed: 37539177
DOI: 10.1016/j.heliyon.2023.e18225 -
Ear, Nose, & Throat Journal Feb 2024
PubMed: 38321760
DOI: 10.1177/01455613241229955 -
Genes Oct 2023Axenfeld-Rieger anomaly (ARA) is a specific ocular disorder that is frequently associated with other systemic abnormalities. and variants explain the majority of...
Axenfeld-Rieger anomaly (ARA) is a specific ocular disorder that is frequently associated with other systemic abnormalities. and variants explain the majority of individuals with Axenfeld-Rieger syndrome (ARS) but leave ~30% unsolved. Here, we present pathogenic/likely pathogenic variants in nine families with ARA/ARS or similar phenotypes affecting five different genes/regions. and explained three families each. was recently linked with syndromic cognitive impairment that includes hearing loss, dental defects, ventriculomegaly, Dandy-Walker malformation, skeletal anomalies (hip dysplasia), and other features showing a significant overlap with -ARS. Anterior segment anomalies are not currently associated with , yet our cases demonstrate ARA, congenital glaucoma, corneal neovascularization, and cataracts. The identification of variants, linked with Alagille syndrome, in three separate families with a clinical diagnosis of ARA/ARS highlights the overlapping features and high variability of these two phenotypes. Finally, intragenic variants in , , and an X chromosome deletion encompassing and (linked with ocular and dental anomalies, correspondingly) were identified in three additional cases with ARS. Accurate diagnosis has important implications for clinical management. We suggest that broad testing such as exome sequencing be applied as a second-tier test for individuals with ARS with normal results for sequencing and copy number analysis, with attention to the described genes/regions.
Topics: Humans; Transcription Factors; Homeodomain Proteins; Anterior Eye Segment; Eye Abnormalities; Ubiquitin Thiolesterase
PubMed: 37895297
DOI: 10.3390/genes14101948 -
Clinical Ophthalmology (Auckland, N.Z.) 2023Axenfeld-Rieger syndrome (ARS) is a rare congenital disease that is primarily characterized by ocular anterior segment anomalies but is also associated with... (Review)
Review
Axenfeld-Rieger syndrome (ARS) is a rare congenital disease that is primarily characterized by ocular anterior segment anomalies but is also associated with craniofacial, dental, cardiac, and neurologic abnormalities. Over half of cases are linked with autosomal dominant mutations in either or , which reflects the molecular role of these genes in regulating neural crest cell contributions to the eye, face, and heart. Within the eye, ARS is classically defined as the combination of posterior embryotoxon with iris bridging strands (Axenfeld anomaly) and iris hypoplasia causing corectopia and pseudopolycoria (Rieger anomaly). Glaucoma due to iridogoniodysgenesis is the main source of morbidity and is typically diagnosed during infancy or childhood in over half of affected individuals. Angle bypass surgery, such as glaucoma drainage devices and trabeculectomies, is often needed to obtain intraocular pressure control. A multi-disciplinary approach including glaucoma specialists and pediatric ophthalmologists produces optimal outcomes as vision is dependent on many factors including glaucoma, refractive error, amblyopia and strabismus. Further, since ophthalmologists often make the diagnosis, it is important to refer patients with ARS to other specialists including dentistry, cardiology, and neurology.
PubMed: 36926528
DOI: 10.2147/OPTH.S379853