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name: Axenfeld-Rieger_syndrome
creation_date: '2025-12-04T16:57:31Z'
updated_date: '2026-02-16T20:19:38Z'
category: Genetic
parents:
- Congenital Eye Disorder
- Craniofacial Disorder
has_subtypes:
- name: Axenfeld-Rieger Syndrome Type 1 (RIEG1)
description: Caused by mutations in the PITX2 gene, characterized by ocular abnormalities and extra-ocular symptoms.
evidence:
- reference: PMID:22199394
reference_title: "Axenfeld-Rieger syndrome: new perspectives."
supports: PARTIAL
snippet: Recent advances in molecular genetics have identified two major genes, PITX2 and FOXC1, demonstrating a wide spectrum of mutations, which aids in the molecular diagnosis of the disease.
explanation: The literature confirms that Axenfeld-Rieger syndrome is associated with mutations in the PITX2 gene and is characterized by ocular abnormalities and extra-ocular symptoms.
- reference: PMID:31341655
reference_title: "Novel PITX2 Mutations including a Mutation Causing an Unusual Ophthalmic Phenotype of Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: The PITX2 gene may be responsible for a significant portion of ARS with additional systemic defects in the Chinese population.
explanation: This reference supports the statement by indicating that mutations in the PITX2 gene are linked to Axenfeld-Rieger syndrome, which includes ocular and systemic manifestations.
- reference: PMID:11092457
reference_title: "Rieger syndrome: a clinical, molecular, and biochemical analysis."
supports: SUPPORT
snippet: Rieger syndrome (RIEG 1; MIM 180500) is an autosomal dominant disorder of morphogenesis. It is a phenotypically heterogeneous disorder characterized by malformations of the eyes, teeth, and umbilicus.
explanation: This reference confirms that Rieger syndrome, also known as Axenfeld-Rieger Syndrome Type 1 (RIEG1), involves ocular and extra-ocular abnormalities.
- name: Axenfeld-Rieger Syndrome Type 3 (RIEG3)
description: Caused by mutations in the FOXC1 gene, associated with similar phenotypic features as Type 1.
evidence:
- reference: PMID:32741584
reference_title: "Sensorineural hearing loss and hypoplastic cochlea in Axenfeld-Rieger syndrome with FOXC1 mutation."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome (ARS) type 3 is a rare autosomal dominant disease, characterized by anterior segment dysgenesis of the eye, hearing loss, and cardiac defects. ARS type 3 is highly associated with FOXC1 mutations, which induces developmental disorders of neural crest cells.
explanation: This reference directly supports the statement that Axenfeld-Rieger Syndrome Type 3 (RIEG3) is caused by mutations in the FOXC1 gene and has similar phenotypic features.
prevalence:
- population: General Population
percentage: 0.001-0.002
evidence:
- reference: PMID:34269512
reference_title: "Frequency of carriers for rare recessive Mendelian diseases in a Brazilian cohort of 320 patients."
supports: NO_EVIDENCE
snippet: The combined frequencies of autosomal recessive diseases were estimated to be 26.39/10,000 (or ~0.26%).
explanation: The study provides the combined frequencies of autosomal recessive diseases but does not specifically mention the prevalence of Axenfeld-Rieger syndrome.
- reference: PMID:33762894
reference_title: "The Prevalence of Clinical Features in Patients with Aarskog-Scott Syndrome and Assessment of Genotype-Phenotype Correlation: A Systematic Review."
supports: NO_EVIDENCE
snippet: Aarskog-Scott syndrome is a genetically and clinically heterogeneous rare condition caused by a pathogenic variant in the FGD1 gene.
explanation: The study focuses on Aarskog-Scott syndrome and does not provide information on the prevalence of Axenfeld-Rieger syndrome.
- reference: PMID:37684520
reference_title: "A population-based survey of FBN1 variants in Iceland reveals underdiagnosis of Marfan syndrome."
supports: NO_EVIDENCE
snippet: Marfan syndrome (MFS) is an autosomal dominant condition characterized by aortic aneurysm, skeletal abnormalities, and lens dislocation, and is caused by variants in the FBN1 gene.
explanation: The study is about Marfan syndrome and does not provide information on the prevalence of Axenfeld-Rieger syndrome.
- reference: PMID:34229749
reference_title: "Genetic epidemiology approach to estimating birth incidence and current disease prevalence for rhizomelic chondrodysplasia punctata."
supports: NO_EVIDENCE
snippet: Rhizomelic chondrodysplasia punctata (RCDP) is an inherited ultra-rare disease which results in severely impaired physical and mental development.
explanation: The study focuses on Rhizomelic chondrodysplasia punctata and does not provide information on the prevalence of Axenfeld-Rieger syndrome.
- reference: PMID:29793789
reference_title: "Axenfeld-Rieger syndrome."
supports: NO_EVIDENCE
snippet: Axenfeld-Rieger syndrome.
explanation: The title indicates the study is about Axenfeld-Rieger syndrome, but it does not provide specific prevalence data in the general population.
- reference: PMID:28513611
reference_title: "Glaucoma spectrum and age-related prevalence of individuals with FOXC1 and PITX2 variants."
supports: NO_EVIDENCE
snippet: Variation in FOXC1 and PITX2 is associated with Axenfeld-Rieger syndrome, characterised by structural defects of the anterior chamber of the eye and a range of systemic features.
explanation: The study discusses the genetic associations and clinical features of Axenfeld-Rieger syndrome but does not provide prevalence data in the general population.
- reference: PMID:36255854
reference_title: "Characteristics of Corneal Endothelium in Axenfeld Rieger Spectrum."
supports: NO_EVIDENCE
snippet: The purpose of this study was to compare the corneal endothelial characteristics in Axenfeld anomaly (AXA), Rieger anomaly (RGA), and Axenfeld-Rieger anomaly/syndrome with age-matched healthy controls.
explanation: The study focuses on corneal endothelial characteristics in patients with Axenfeld-Rieger syndrome and does not provide prevalence data in the general population.
- reference: PMID:32357855
reference_title: "Surgical outcomes of Glaucoma associated with Axenfeld-Rieger syndrome."
supports: NO_EVIDENCE
snippet: The surgical management of glaucoma associated with Axenfeld-Rieger Syndrome (ARS) is poorly described in the literature.
explanation: The study discusses the surgical outcomes of glaucoma associated with Axenfeld-Rieger syndrome but does not provide prevalence data in the general population.
- reference: PMID:9618168
reference_title: "Mutation in the RIEG1 gene in patients with iridogoniodysgenesis syndrome."
supports: NO_EVIDENCE
snippet: Axenfeld-Rieger syndrome (ARS) and iridogoniodysgenesis syndrome (IGDS) are clinically related autosomal dominant disorders which affect the anterior segment of the eye as well as non-ocular structures.
explanation: The study discusses the genetic and clinical relationship between Axenfeld-Rieger syndrome and iridogoniodysgenesis syndrome but does not provide prevalence data in the general population.
pathophysiology:
- name: Disrupted Neural Crest-Derived Periocular Mesenchyme Development
description: PITX2 and FOXC1 haploinsufficiency in cranial neural crest-derived periocular mesenchyme disrupts signaling integration (retinoic acid-PITX2-DKK2 pathway, Hippo/YAP-TAZ-FOXC1 axis, TGF-beta/ECM interactions) leading to failure of normal regression of transient mesenchyme at the iridocorneal angle and maldevelopment of trabecular meshwork and Schlemm's canal.
cell_types:
- preferred_term: migratory neural crest cell
term:
id: CL:0000333
label: migratory neural crest cell
biological_processes:
- preferred_term: neural crest cell migration
term:
id: GO:0001755
label: neural crest cell migration
- preferred_term: eye morphogenesis
term:
id: GO:0048592
label: eye morphogenesis
- preferred_term: canonical Wnt signaling pathway
term:
id: GO:0060070
label: canonical Wnt signaling pathway
locations:
- preferred_term: trabecular meshwork
term:
id: UBERON:0005969
label: eye trabecular meshwork
- preferred_term: corneal endothelium
term:
id: UBERON:0001985
label: corneal endothelium
- preferred_term: iris stroma
term:
id: UBERON:0001779
label: iris stroma
evidence:
- reference: PMID:22199394
reference_title: "Axenfeld-Rieger syndrome: new perspectives."
supports: PARTIAL
snippet: Recent advances in molecular genetics have identified two major genes, PITX2 and FOXC1, demonstrating a wide spectrum of mutations, which aids in the molecular diagnosis of the disease.
explanation: Confirms PITX2 and FOXC1 as the primary genes involved in ARS pathogenesis.
- name: Dysregulated Transcription Factor Activity
description: Mutations in the PITX2 gene disrupt its function as a transcription factor, impairing its ability to bind DNA and regulate gene expression critical for eye development. Most mutations cause defects in DNA binding or transcriptional activation, while some increase transactivation activity, leading to unregulated gene expression during embryogenesis.
biological_processes:
- preferred_term: regulation of transcription by RNA polymerase II
term:
id: GO:0006357
label: regulation of transcription by RNA polymerase II
- preferred_term: extracellular matrix organization
term:
id: GO:0030198
label: extracellular matrix organization
evidence:
- reference: PMID:19218601
reference_title: "Analysis of mutations of the PITX2 transcription factor found in patients with Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: Two homeobox mutations, R43W and R90C, resulted in severely reduced DNA-binding and transcriptional activation despite normal nuclear localization.
explanation: The reference indicates that some mutations in PITX2 result in reduced DNA-binding and transcriptional activation, which aligns with the statement that mutations disrupt its function.
- reference: PMID:15509533
reference_title: "PITX2 gain-of-function in Rieger syndrome eye model."
supports: SUPPORT
snippet: It has been reported that some mutations in PITX2 increase transactivation, whereas most mutations cause defects in DNA binding or transactivation.
explanation: This reference supports the statement that mutations in PITX2 can disrupt its function, and mentions that some mutations can increase transactivation activity.
- reference: PMID:12130547
reference_title: "Regulation of prolactin, GH, and Pit-1 gene expression in anterior pituitary by Pitx2: An approach using Pitx2 mutants."
supports: SUPPORT
snippet: The five mutants appeared to be transcriptionally defective despite conserved DNA-binding in CV1 cells.
explanation: This reference supports the idea that PITX2 mutations can impair its ability to regulate gene expression.
- reference: PMID:21837767
reference_title: "Digenic inheritance of mutations in FOXC1 and PITX2 : correlating transcription factor function and Axenfeld-Rieger disease severity."
supports: SUPPORT
snippet: Mutation in either gene caused reduced transcriptional activation to different extents on the FOXO1 and PLOD1 promoters.
explanation: This reference supports the idea that PITX2 mutations can disrupt its function as a transcription factor.
- name: Ocular Anomalies
description: Improper development of the anterior segment of the eye, leading to issues such as iris defects and abnormal angle structures.
evidence:
- reference: PMID:36926528
reference_title: "Ophthalmological Manifestations of Axenfeld-Rieger Syndrome: Current Perspectives."
supports: SUPPORT
snippet: 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.
explanation: The literature states that ARS is characterized by ocular anterior segment anomalies, supporting the statement that it involves improper development of the anterior segment of the eye.
- reference: PMID:12015278
reference_title: "Anterior segment dysgenesis and the developmental glaucomas are complex traits."
supports: SUPPORT
snippet: Individuals with malformations of structures of the anterior segment of the eye frequently develop elevated intraocular pressure and glaucoma.
explanation: The reference confirms that malformations of the anterior segment of the eye are associated with conditions like glaucoma, supporting the statement about improper development and associated issues.
- reference: PMID:35327965
reference_title: "Variable Anterior Segment Dysgenesis and Cardiac Anomalies Caused by a Novel Truncating Variant of FOXC1."
supports: SUPPORT
snippet: Anterior segment dysgenesis (ASD) encompasses a wide spectrum of developmental abnormalities of the anterior ocular segment, including congenital cataract, iris hypoplasia, aniridia, iridocorneal synechiae, as well as Peters, Axenfeld, and Rieger anomalies.
explanation: The literature describes Axenfeld and Rieger anomalies as part of anterior segment dysgenesis, which includes iris defects and abnormal angle structures, supporting the statement.
- reference: PMID:31560925
reference_title: "Aniridia and Axenfeld-Rieger Syndrome: Clinical presentations, molecular genetics and current/emerging therapies."
supports: SUPPORT
snippet: Aniridia and Axenfeld-Rieger Syndrome are related, human ocular disorders that are typically inherited in an autosomal dominant manner. Both result from incorrect development of the eye and have, as their most serious consequences, elevated risk to develop the blinding condition glaucoma.
explanation: The literature confirms that Axenfeld-Rieger Syndrome results from incorrect development of the eye, specifically mentioning the anterior segment, supporting the statement.
- name: Systemic Anomalies
description: Involves multiple systems, often including dental, craniofacial, and umbilical abnormalities.
evidence:
- reference: PMID:16302606
reference_title: "Axenfeld-Rieger syndrome: report on dental and craniofacial findings."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome is a rare autosomal dominant disorder characterized by various ocular and extraocular malformations. Dental abnormalities are considered as definitive features for the diagnosis and differentiation of Rieger syndrome from other anterior chamber of the eye malformations.
explanation: The literature describes Axenfeld-Rieger syndrome as involving multiple systems, including dental and craniofacial abnormalities, which supports the statement.
- reference: PMID:36543336
reference_title: "Cardiac anomalies in Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome is a rare multi-system disorder associated with cardiac anomalies.
explanation: The reference confirms that Axenfeld-Rieger syndrome is a multi-system disorder, which aligns with the statement that it involves multiple systems.
- reference: PMID:18599376
reference_title: "The genetic basis of inherited anomalies of the teeth. Part 2: syndromes with significant dental involvement."
supports: NO_EVIDENCE
snippet: We will consider successively syndromic forms of amelogenesis imperfecta or enamel defects, dentinogenesis imperfecta (i.e. osteogenesis imperfecta) and other dentine anomalies.
explanation: The literature mentions dental anomalies as significant features in various syndromes, including Axenfeld-Rieger syndrome, supporting the statement.
- name: Glaucoma-related Vision Loss
frequency: OCCASIONAL
description: Loss of vision due to uncontrolled intraocular pressure.
evidence:
- reference: PMID:35733478
reference_title: "Progressive Vision Loss in a Patient With Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: Treatment is predominantly the management of glaucoma and is mostly medical but can be surgical in refractory cases.
explanation: The reference discusses the management of glaucoma in Axenfeld-Rieger syndrome, indicating that loss of vision due to uncontrolled intraocular pressure is a concern.
- reference: PMID:33367186
reference_title: "Ocular hypertension in Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: Glaucoma is the main cause of visual morbidity in patients with ARS.
explanation: The reference explicitly states that glaucoma is the main cause of visual morbidity in Axenfeld-Rieger syndrome, supporting the statement.
- reference: PMID:28549150
reference_title: "Primary congenital and developmental glaucomas."
supports: SUPPORT
snippet: Other early-onset glaucomas may arise secondary to developmental abnormalities, such as glaucomas that occur with aniridia or as part of Axenfeld-Rieger syndrome.
explanation: The reference mentions that glaucomas associated with Axenfeld-Rieger syndrome can lead to visual disability, supporting the statement.
- reference: PMID:5467709
reference_title: "Glaucoma and Rieger's syndrome."
supports: PARTIAL
snippet: Glaucoma and Rieger's syndrome.
explanation: The title suggests a direct relationship between glaucoma and Axenfeld-Rieger syndrome, implying that vision loss due to glaucoma is a concern.
phenotypes:
- category: Ophthalmologic
name: Glaucoma
frequency: VERY_FREQUENT
severity: Severe
diagnostic: true
notes: Early onset, often leading to vision loss if untreated. Abnormal development of the anterior segment due to defective PITX2 function leads to poor aqueous humor drainage, resulting in elevated intraocular pressure and glaucoma.
evidence:
- reference: PMID:22199394
reference_title: "Axenfeld-Rieger syndrome: new perspectives."
supports: SUPPORT
snippet: In the eye, this condition manifests with varying degrees of anterior segment dysgenesis and carries a high risk of glaucoma.
explanation: The literature states that Axenfeld-Rieger syndrome carries a high risk of glaucoma, supporting the statement.
- reference: PMID:12015278
reference_title: "Anterior segment dysgenesis and the developmental glaucomas are complex traits."
supports: SUPPORT
snippet: Individuals with malformations of structures of the anterior segment of the eye frequently develop elevated intraocular pressure and glaucoma.
explanation: The literature confirms that malformations of the anterior segment, which are characteristic of Axenfeld-Rieger syndrome, frequently lead to glaucoma.
- reference: PMID:27055677
reference_title: "Early-onset glaucoma in Axenfeld-Rieger anomaly: long-term surgical results and visual outcome."
supports: SUPPORT
snippet: To determine the long-term surgical and visual outcomes in Indian children with early-onset glaucoma associated with Axenfeld-Rieger anomaly (ARA).
explanation: The study specifically investigates early-onset glaucoma associated with Axenfeld-Rieger anomaly, supporting the statement.
- reference: PMID:32905845
reference_title: "FOXC1 variant in a family with anterior segment dysgenesis and normal-tension glaucoma."
supports: SUPPORT
snippet: Our study describes the glaucoma phenotype in a family with Axenfeld-Rieger syndrome (ARS) and a FOXC1 variant.
explanation: The literature describes glaucoma phenotypes in individuals with Axenfeld-Rieger syndrome, supporting the statement.
- reference: PMID:33367186
reference_title: "Ocular hypertension in Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: Glaucoma is the main cause of visual morbidity in patients with ARS, therefore a complete periodic ophthalmological exam is a priority.
explanation: The literature states that glaucoma is a major cause of visual morbidity in Axenfeld-Rieger syndrome, supporting the statement.
- reference: PMID:21666320
reference_title: "Unusual presentation in Axenfeld-Rieger syndrome."
supports: PARTIAL
snippet: The patient had megalocornea with Haab's striae in the right eye and posterior embryotoxon in both the eyes. In the left eye, there was a white cord-like structure traversing the anterior chamber with adhesions to iris tissue along its course.
explanation: The literature describes ocular abnormalities consistent with glaucoma in Axenfeld-Rieger syndrome, supporting the statement.
- reference: PMID:15509533
reference_title: "PITX2 gain-of-function in Rieger syndrome eye model."
supports: SUPPORT
snippet: The eye manifests with iris ruptures, irido-corneal adhesions, cloudy corneas, and glaucoma.
explanation: The literature explicitly states that glaucoma is a manifestation of Axenfeld-Rieger syndrome, supporting the statement.
phenotype_term:
preferred_term: Glaucoma
term:
id: HP:0000501
label: Glaucoma
- category: Ophthalmologic
name: Posterior Embryotoxon
frequency: VERY_FREQUENT
severity: Mild
diagnostic: true
notes: A prominent, anteriorly displaced Schwalbe's line seen on eye examination.
evidence:
- reference: PMID:15492748
reference_title: "Posterior embryotoxon may not be a forme fruste of Axenfeld-Rieger's Syndrome."
supports: PARTIAL
snippet: One of the main ocular features associated with Axenfeld-Rieger is posterior embryotoxon, which is a prominent anteriorly displaced Schwalbe's line. This can be found in up to 15% of normal eyes, without any clinical significance or may represent a forme fruste of an anterior segment dysgenesis.
explanation: The literature supports that posterior embryotoxon is a common feature of Axenfeld-Rieger syndrome but does not confirm it as 'VERY_FREQUENT'. Additionally, it may be present without clinical significance.
- reference: PMID:21666320
reference_title: "Unusual presentation in Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: The patient had megalocornea with Haab's striae in the right eye and posterior embryotoxon in both the eyes.
explanation: The case report supports the presence of posterior embryotoxon in Axenfeld-Rieger syndrome.
- reference: PMID:34937757
reference_title: "Hyperproliferative embryotoxon simulating double cornea."
supports: SUPPORT
snippet: Posterior embryotoxon, an anteriorly displaced Schwalbe's line, is the most common feature of Axenfeld Rieger syndrome.
explanation: This reference confirms that posterior embryotoxon is a common feature of Axenfeld-Rieger syndrome.
- reference: PMID:38006999
reference_title: "Posterior embryotoxon as the initial ophthalmological sign of Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: Posterior embryotoxon as the initial ophthalmological sign of Axenfeld-Rieger syndrome.
explanation: This reference supports the statement that posterior embryotoxon is a diagnostic feature of Axenfeld-Rieger syndrome.
phenotype_term:
preferred_term: Posterior Embryotoxon
term:
id: HP:0000627
label: Posterior embryotoxon
- category: Ophthalmologic
name: Iris Hypoplasia
frequency: VERY_FREQUENT
notes: Underdevelopment of the iris, may include corectopia (displacement of the pupil). Mutations like the V45L variant cause reduced DNA-binding with increased transactivation, disrupting iris development due to unregulated gene expression during embryogenesis.
evidence:
- reference: PMID:30860739
reference_title: "Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: This anomaly encompasses posterior embryotoxon, iris hypoplasia, polycoria, and corectopia.
explanation: The literature clearly states that iris hypoplasia is a component of the Rieger anomaly, which is part of Axenfeld-Rieger syndrome.
- reference: PMID:35327965
reference_title: "Variable Anterior Segment Dysgenesis and Cardiac Anomalies Caused by a Novel Truncating Variant of FOXC1."
supports: SUPPORT
snippet: Anterior segment dysgenesis (ASD) encompasses a wide spectrum of developmental abnormalities of the anterior ocular segment, including congenital cataract, iris hypoplasia, aniridia, iridocorneal synechiae, as well as Peters, Axenfeld, and Rieger anomalies.
explanation: The literature confirms that iris hypoplasia is a frequent feature of anterior segment dysgenesis, which includes Axenfeld-Rieger anomalies.
- reference: PMID:11740218
reference_title: "Screening for mutations of Axenfeld-Rieger syndrome caused by FOXC1 gene in Japanese patients."
supports: SUPPORT
snippet: In pedigrees 1,2, and 4, younger generations had iris hypoplasia with severe early-onset glaucoma, whereas their parents had posterior embryotoxon without glaucoma.
explanation: The literature identifies iris hypoplasia as a clinical feature in multiple pedigrees with Axenfeld-Rieger syndrome.
- category: Ophthalmologic
name: Corectopia
frequency: FREQUENT
notes: Displacement of the pupil from its normal central position, often observed alongside iris hypoplasia and other anterior segment abnormalities.
evidence:
- reference: PMID:30860739
reference_title: "Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: This anomaly encompasses posterior embryotoxon, iris hypoplasia, polycoria, and corectopia.
explanation: The literature explicitly lists corectopia as a component of Rieger anomaly in Axenfeld-Rieger syndrome.
- category: Craniofacial
name: Dental Anomalies
frequency: FREQUENT
notes: Includes missing teeth (hypodontia), small teeth (microdontia), and enamel hypoplasia. Highly penetrant in PITX2-related cases.
phenotype_term:
preferred_term: Abnormal dental morphology
term:
id: HP:0006482
label: Abnormal dental morphology
evidence:
- reference: PMID:16302606
reference_title: "Axenfeld-Rieger syndrome: report on dental and craniofacial findings."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome is a rare autosomal dominant disorder characterized by various ocular and extraocular malformations. Dental abnormalities are considered as definitive features for the diagnosis and differentiation of Rieger syndrome from other anterior chamber of the eye malformations.
explanation: The abstract confirms dental abnormalities are definitive features of Rieger syndrome.
- reference: PMID:35836351
reference_title: "Enamel defects of Axenfeld-Rieger syndrome and the role of PITX2 in its pathogenesis."
supports: PARTIAL
snippet: Enamel formation is disturbed in some patients with ARS. Pitx2 knockdown can influence the proliferation and ameloblast differentiation of inner enamel epithelial cells, and PITX2 may regulate cell proliferation via Wnt/beta-catenin signaling pathway.
explanation: This study provides evidence for enamel hypoplasia in some patients with Axenfeld-Rieger syndrome but does not provide information on the frequency or other dental anomalies such as hypodontia or microdontia.
- category: Craniofacial
name: Craniofacial Dysmorphism
frequency: FREQUENT
notes: Includes features such as an underdeveloped maxilla, broad nasal bridge, and hypertelorism (increased distance between the eyes). Hypertelorism is significantly more prevalent in FOXC1 variants (81.8%) compared to PITX2 variants (25.0%).
phenotype_term:
preferred_term: Hypertelorism
term:
id: HP:0000316
label: Hypertelorism
evidence:
- reference: PMID:16302606
reference_title: "Axenfeld-Rieger syndrome: report on dental and craniofacial findings."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome is a rare autosomal dominant disorder characterized by various ocular and extraocular malformations. ... Significant cranio-dento-facial findings that have been observed are, teeth with short and dilacerated roots, hyperplastic frenums and underdeveloped maxilla.
explanation: The literature confirms that craniofacial dysmorphism, including an underdeveloped maxilla, is a feature of Axenfeld-Rieger syndrome.
- reference: PMID:33231930
reference_title: "Gene-specific facial dysmorphism in Axenfeld-Rieger syndrome caused by FOXC1 and PITX2 variants."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome is a genetic condition characterized by ocular and systemic features. ... A thin upper lip (55.9%) and a prominent forehead (41.2%) were common facial features shared between both genes. Hypertelorism/telecanthus (81.8% vs 25.0%, p = 0.002) and low-set ears (31.8% vs 0.0%, p = 0.036) were significantly more prevalent in individuals with FOXC1 variants compared with PITX2 variants.
explanation: The literature indicates that hypertelorism, a craniofacial feature, is frequently observed in individuals with Axenfeld-Rieger syndrome.
- category: Systemic
name: Redundant Periumbilical Skin
frequency: OCCASIONAL
notes: Extra fold of skin around the belly button. Often considered a diagnostic feature. Highly penetrant in PITX2-related cases.
evidence:
- reference: PMID:27070436
reference_title: "The 6p25 deletion syndrome: An update on a rare neurocristopathy."
supports: SUPPORT
snippet: Key clinical features comprise facial dysmorphism including mid-face and dental hypoplasia, hearing loss, cardiac anomalies, and involuted periumbilical skin.
explanation: The mention of 'involuted periumbilical skin' aligns with the statement's description of 'Redundant Periumbilical Skin.'
- category: Systemic
name: Hearing Loss
frequency: OCCASIONAL
notes: Sensorineural hearing loss observed in some patients, particularly those with FOXC1 variants.
phenotype_term:
preferred_term: Hearing impairment
term:
id: HP:0000365
label: Hearing impairment
evidence:
- reference: PMID:27070436
reference_title: "The 6p25 deletion syndrome: An update on a rare neurocristopathy."
supports: SUPPORT
snippet: Key clinical features comprise facial dysmorphism including mid-face and dental hypoplasia, hearing loss, cardiac anomalies, and involuted periumbilical skin.
explanation: The literature mentions hearing loss as a clinical feature of Axenfeld-Rieger syndrome.
- reference: PMID:32741584
reference_title: "Sensorineural hearing loss and hypoplastic cochlea in Axenfeld-Rieger syndrome with FOXC1 mutation."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome (ARS) type 3 is a rare autosomal dominant disease, characterized by anterior segment dysgenesis of the eye, hearing loss, and cardiac defects.
explanation: This reference confirms hearing loss is associated with ARS type 3 (FOXC1-related).
- category: Systemic
name: Congenital Heart Defects
frequency: OCCASIONAL
notes: Cardiac anomalies including endocardial cushion defects and other structural heart malformations. More prevalent in FOXC1-related cases.
phenotype_term:
preferred_term: Congenital heart defect
term:
id: HP:0001627
label: Abnormal heart morphology
evidence:
- reference: PMID:32741584
reference_title: "Sensorineural hearing loss and hypoplastic cochlea in Axenfeld-Rieger syndrome with FOXC1 mutation."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome (ARS) type 3 is a rare autosomal dominant disease, characterized by anterior segment dysgenesis of the eye, hearing loss, and cardiac defects.
explanation: This reference confirms cardiac defects are associated with ARS type 3 (FOXC1-related).
- reference: PMID:36543336
reference_title: "Cardiac anomalies in Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome is a rare multi-system disorder associated with cardiac anomalies.
explanation: The reference confirms that cardiac anomalies are part of the multi-system presentation of Axenfeld-Rieger syndrome.
diagnosis:
- name: Genetic Testing
notes: Identifies mutations in PITX2, FOXC1 or other associated genes.
evidence:
- reference: PMID:11821690
reference_title: "Genetic analysis of PITX2 and FOXC1 in Rieger Syndrome patients from Brazil."
supports: SUPPORT
snippet: This study examined the two genes known to cause Rieger syndrome, PITX2 and FOXC1, for mutations in five Brazilian families with Axenfeld-Rieger syndrome.
explanation: The study confirms that genetic testing identifies mutations in PITX2 and FOXC1 in patients with Axenfeld-Rieger syndrome.
- reference: PMID:25893250
reference_title: "PITX2 Loss-of-Function Mutation Contributes to Congenital Endocardial Cushion Defect and Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: A novel heterozygous PITX2 mutation... was identified in a family with endocardial cushion defect (ECD) and Axenfeld-Rieger syndrome (ARS).
explanation: The study identifies a PITX2 mutation in a family with Axenfeld-Rieger syndrome, supporting the statement.
- reference: PMID:28730073
reference_title: "A Chinese family with Axenfeld-Rieger syndrome: report of the clinical and genetic findings."
supports: SUPPORT
snippet: Genome-wide linkage and exome sequencing analyses showed PITX2 as the disease candidate gene.
explanation: The study identifies PITX2 as the gene responsible for the disease in a Chinese family with Axenfeld-Rieger syndrome.
- reference: PMID:15654696
reference_title: "Axenfeld-Rieger malformation and distinctive facial features: Clues to a recognizable 6p25 microdeletion syndrome."
supports: SUPPORT
snippet: Detailed analysis confirmed deletion of the FOXC1 forkhead gene cluster at 6p25.
explanation: The study confirms the involvement of FOXC1 in Axenfeld-Rieger syndrome.
- reference: PMID:28611552
reference_title: "A Novel Mutation in PITX2 in a Patient with Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: A variant of uncertain significance in PITX2 was identified.
explanation: The study reports a variant in PITX2 in a patient with Axenfeld-Rieger syndrome, supporting the role of genetic testing in identifying mutations in this gene.
- reference: PMID:10713890
reference_title: "Axenfeld-Rieger syndrome resulting from mutation of the FKHL7 gene on chromosome 6p25."
supports: SUPPORT
snippet: Mutations in the forkhead-like 7 (FKHL7) gene have been recently shown to cause juvenile glaucoma and anterior segment anomalies.
explanation: The study identifies FKHL7 (now known as FOXC1) as a gene associated with Axenfeld-Rieger syndrome.
- name: Slit-lamp Examination
notes: Used to observe anterior segment anomalies such as posterior embryotoxon and iris defects.
evidence:
- reference: PMID:15492748
reference_title: "Posterior embryotoxon may not be a forme fruste of Axenfeld-Rieger's Syndrome."
supports: SUPPORT
snippet: One of the main ocular features associated with Axenfeld-Rieger is posterior embryotoxon, which is a prominent anteriorly displaced Schwalbe's line.
explanation: The abstract mentions that posterior embryotoxon is a key feature observed in Axenfeld-Rieger syndrome, which can be detected using slit-lamp examination.
- reference: PMID:808872
reference_title: "Anterior chamber cleavage syndrome. A stepladder classification."
supports: SUPPORT
snippet: The peripheral anomalies consist of a prominent Schwalbe's ring, iris strands to Schwalbe's ring, and hypoplasia of the anterior iris stroma.
explanation: The study classifies anterior segment anomalies, including posterior embryotoxon and iris defects, which can be observed using slit-lamp examination.
- reference: PMID:36255854
reference_title: "Characteristics of Corneal Endothelium in Axenfeld Rieger Spectrum."
supports: SUPPORT
snippet: Patients with AXA, RGA, and Axenfeld-Rieger anomaly/syndrome have lower ECD and increased MCA compared with normal eyes.
explanation: The study discusses various features of Axenfeld-Rieger syndrome, including anterior segment anomalies that can be observed via slit-lamp examination.
- reference: PMID:33367186
reference_title: "Ocular hypertension in Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: In the biomicroscopy, a posterior embryotoxon, iris atrophy with absence of crypts and irregularity of pigmentation, and discoria in OU were observed.
explanation: The case report describes the use of slit-lamp examination to observe posterior embryotoxon and iris defects in a patient with Axenfeld-Rieger syndrome.
- name: Intraocular Pressure Measurement
notes: Elevated pressure indicating glaucoma, which is common in these patients.
evidence:
- reference: PMID:33367186
reference_title: "Ocular hypertension in Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: Glaucoma is the main cause of visual morbidity in patients with ARS, therefore a complete periodic ophthalmological exam is a priority.
explanation: The literature confirms that glaucoma, which is associated with elevated intraocular pressure, is a common issue in patients with Axenfeld-Rieger Syndrome (ARS).
- reference: PMID:5467709
reference_title: "Glaucoma and Rieger's syndrome."
supports: SUPPORT
snippet: Glaucoma and Rieger's syndrome.
explanation: The title of the reference directly links glaucoma, which involves elevated intraocular pressure, with Rieger's syndrome (a component of Axenfeld-Rieger Syndrome).
genetic:
- name: PITX2
association: Pathogenic Variants
notes: Paired-like homeodomain transcription factor critical for periocular mesenchyme differentiation and anterior segment development. Regulates WNT signaling through DKK2 induction and controls ECM/collagen gene expression. Associated with ARS Type 1 (RIEG1).
evidence:
- reference: PMID:28611552
reference_title: "A Novel Mutation in PITX2 in a Patient with Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: Axenfeld-Rieger syndrome is a rare autosomal dominant condition... A variant of uncertain significance in PITX2 was identified... it is suggested that this variant can be classified as pathogenic.
explanation: The study identifies a pathogenic variant in PITX2 associated with Axenfeld-Rieger syndrome, which is an autosomal dominant condition.
- reference: PMID:37539177
reference_title: "Axenfeld-Rieger syndrome: A systematic review examining genetic, neurological, and neurovascular associations to inform screening."
supports: SUPPORT
snippet: Mutations in the transcription factors FOXC1 or PITX2 are the most well-studied genetic manifestations of this syndrome.
explanation: The review supports the association of PITX2 pathogenic variants with Axenfeld-Rieger syndrome.
- reference: PMID:36442680
reference_title: "Genotype-phenotype association of PITX2 and FOXC1 in Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: PITX2 and FOXC1 are the most common pathogenic genes associated with Axenfeld-Rieger syndrome (ARS).
explanation: The study confirms that PITX2 is a common pathogenic gene in Axenfeld-Rieger syndrome, which is autosomal dominant.
- reference: PMID:9685346
reference_title: "The molecular basis of Rieger syndrome. Analysis of Pitx2 homeodomain protein activities."
supports: SUPPORT
snippet: Mutations in the Pitx2 homeobox gene have been linked to Rieger syndrome.
explanation: The study identifies PITX2 mutations as linked to Rieger syndrome, which is a part of the Axenfeld-Rieger syndrome spectrum.
- name: FOXC1
association: Pathogenic Variants
notes: Forkhead transcription factor with dosage-sensitive regulation of neural crest derivatives, trabecular meshwork development, and ocular/endothelial programs. Controls CD98-mTOR axis in retinal angiogenesis. Associated with ARS Type 3 (RIEG3) and earlier glaucoma onset compared to PITX2 variants.
evidence:
- reference: PMID:34809627
reference_title: "A novel variant in FOXC1 associated with atypical Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: Mutations in the Forkhead Box C1 (FOXC1) are known to cause autosomal dominant hereditary Axenfeld-Rieger syndrome...
explanation: This reference explicitly states that mutations in FOXC1 cause autosomal dominant Axenfeld-Rieger syndrome.
- reference: PMID:37539177
reference_title: "Axenfeld-Rieger syndrome: A systematic review examining genetic, neurological, and neurovascular associations to inform screening."
supports: SUPPORT
snippet: Mutations in the transcription factors FOXC1 or PITX2 are the most well-studied genetic manifestations of this syndrome.
explanation: This reference confirms the association of FOXC1 with Axenfeld-Rieger syndrome and describes the genetic nature of the condition.
- reference: PMID:22009788
reference_title: "Axenfeld-Rieger anomaly and Axenfeld-Rieger syndrome: clinical, molecular-cytogenetic, and DNA array analyses of three patients with chromosomal defects at 6p25."
supports: SUPPORT
snippet: Clinical phenotypes of and genetic aberrations in three unrelated Japanese patients with Axenfeld-Rieger anomalies... FOXC1 was apparently deleted in both patients.
explanation: This reference supports the association of FOXC1 with Axenfeld-Rieger syndrome through genetic analysis.
- reference: PMID:33530637
reference_title: "The Axenfeld-Rieger Syndrome Gene FOXC1 Contributes to Left-Right Patterning."
supports: SUPPORT
snippet: Mutations of one cascade constituent PITX2 and, separately, the Forkhead transcription factor FOXC1 independently cause a multi-system disorder known as Axenfeld-Rieger syndrome (ARS).
explanation: This reference supports the statement by identifying FOXC1 mutations as a cause of Axenfeld-Rieger syndrome.
variants:
- name: p.Val136Leu
gene:
preferred_term: PITX2
clinical_significance: PATHOGENIC
type: single_nucleotide_variant
sequence_length: 1
synonyms:
- V45L
identifiers:
- OMIM:601542.0010
- dbSNP:rs121909249
functional_effects:
- function: DNA binding
description: tenfold reduction
type: loss-of-function
- function: DNA-binding transcription factor activity
description: increases 200%
evidence:
- reference: PMID:19218601
reference_title: "Analysis of mutations of the PITX2 transcription factor found in patients with Axenfeld-Rieger syndrome."
supports: NO_EVIDENCE
snippet: Two homeobox mutations, R43W and R90C, resulted in severely reduced DNA-binding and transcriptional activation despite normal nuclear localization. L105V, located C-terminal to the homeodomain, resulted in normal localization, reporter gene transactivation, and protein half-life, but with an altered mobility shift pattern of protein-DNA complexes. N108T, also located C-terminal to the homeodomain, resulted in an altered mobility shift pattern and with slightly increased reporter transactivation and shortened protein half-life.
explanation: This study does not mention the p.Val136Leu (V45L) variant. It discusses other PITX2 mutations but does not provide evidence for the specific variant mentioned in the statement.
- reference: PMID:28611552
reference_title: "A Novel Mutation in PITX2 in a Patient with Axenfeld-Rieger Syndrome."
supports: NO_EVIDENCE
snippet: The mutation, NM_153427.2:c.272G>A (p.Arg91Gln), is predicted to be damaging by PolyPhen-2 (score of 0.997), identified as a missense mutation with an allele frequency of 1.648e-05 by the Exome Aggregation Consortium, and has been reported in ClinVar once, by the laboratory that analyzed our patient's sample.
explanation: This study discusses a different PITX2 mutation (p.Arg91Gln) and does not provide evidence for the p.Val136Leu (V45L) variant.
- reference: PMID:9685346
reference_title: "The molecular basis of Rieger syndrome. Analysis of Pitx2 homeodomain protein activities."
supports: NO_EVIDENCE
snippet: We next studied two Rieger mutants. A threonine to proline mutation (T68P) in the second helix of the homeodomain retained DNA binding activity with the same apparent KD and only about a 2-fold reduction in the Bmax. However, this mutant did not transactivate reporter genes containing the bicoid site.
explanation: This study investigates different PITX2 mutations (T68P and L54Q) and does not provide evidence for the p.Val136Leu (V45L) variant.
environmental:
- name: Not Applicable
notes: There are no significant environmental factors specifically associated with the onset of Axenfeld-Rieger syndrome.
evidence:
- reference: PMID:29793789
reference_title: "Axenfeld-Rieger syndrome."
supports: NO_EVIDENCE
snippet: Axenfeld-Rieger syndrome.
explanation: The provided literature does not discuss any significant environmental factors associated with the onset of Axenfeld-Rieger syndrome.
- reference: PMID:15492748
reference_title: "Posterior embryotoxon may not be a forme fruste of Axenfeld-Rieger's Syndrome."
supports: NO_EVIDENCE
snippet: Axenfeld-Rieger Syndrome is a disorder of morphogenesis which is autosomal dominantly inherited.
explanation: The literature describes Axenfeld-Rieger syndrome as a genetic disorder, with no mention of environmental factors influencing its onset.
- reference: PMID:12210347
reference_title: "Familial Axenfeld-Rieger anomaly, cardiac malformations, and sensorineural hearing loss: a provisionally unique genetic syndrome?"
supports: NO_EVIDENCE
snippet: Axenfeld-Rieger anomaly (ARA) is an autosomal dominant disorder of the anterior chamber of the eye.
explanation: The literature focuses on genetic factors and does not mention any environmental factors.
- reference: PMID:3104560
reference_title: "Dental and craniofacial anomalies of Axenfeld-Rieger syndrome."
supports: NO_EVIDENCE
snippet: Apart from the three distinguishing findings for the diagnosis of Axenfeld-Rieger syndrome (oligodontia, failure of periumbilical skin to involute, and ocular anterior chamber defects)...
explanation: The literature discusses clinical and genetic aspects of Axenfeld-Rieger syndrome, without mentioning environmental factors.
- reference: PMID:37822332
reference_title: "A patient with concurrent Axenfeld-Rieger and Stickler syndromes verified by molecular genetics."
supports: NO_EVIDENCE
snippet: Genetic analysis confirmed heterozygous pathogenic variants in both the FOXC1 and COL2A1 genes, leading to the concurrent diagnoses of Axenfeld-Rieger and Stickler syndromes.
explanation: The literature emphasizes genetic mutations as the cause of Axenfeld-Rieger syndrome.
- reference: PMID:12381896
reference_title: "Four novel mutations in the PITX2 gene in patients with Axenfeld-Rieger syndrome."
supports: NO_EVIDENCE
snippet: Mutational screening and sequence analysis of the PITX2 gene was performed in four families previously diagnosed with Rieger syndrome.
explanation: The literature focuses on genetic mutations in the PITX2 gene and does not discuss environmental factors.
- reference: PMID:32045938
reference_title: "Axenfeld-Rieger Anomaly and Neuropsychiatric Problems-More than Meets the Eye."
supports: NO_EVIDENCE
snippet: We report on two adolescent individuals with ocular anterior segment dysgenesis (Axenfeld-Rieger anomaly) presenting with neuropsychiatric symptoms.
explanation: The literature discusses genetic mutations and associated neuropsychiatric symptoms, with no mention of environmental factors.
- reference: PMID:11004268
reference_title: "Axenfeld-Rieger syndrome in the age of molecular genetics."
supports: NO_EVIDENCE
snippet: Axenfeld-Rieger syndrome is a term that can be used to describe a variety of overlapping phenotypes. To date, at least three known genetic loci can cause these disorders.
explanation: The literature reviews genetic loci associated with Axenfeld-Rieger syndrome and does not mention environmental factors.
- reference: PMID:26281856
reference_title: "Axenfeld-Rieger syndrome: a case report."
supports: NO_EVIDENCE
snippet: Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant condition manifesting as a heterogeneous group of features.
explanation: The literature describes Axenfeld-Rieger syndrome as a genetic condition, with no mention of environmental factors.
treatments:
- name: Glaucoma Pharmacotherapy
description: Topical medications to reduce intraocular pressure, including prostaglandin analogs, beta-blockers, alpha-agonists, and carbonic anhydrase inhibitors. First-line treatment for glaucoma management.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
evidence:
- reference: PMID:18929112
reference_title: "Laser therapies for glaucoma: new frontiers."
supports: SUPPORT
snippet: Treatment for glaucoma consists of reducing intraocular pressure (IOP) to an acceptable target range to prevent further optic-nerve damage. Currently available treatments include topical drug (single then multidrug combinations) followed, for those patients on maximal tolerated medical therapy who still need additional IOP reduction, by laser treatments.
explanation: This reference supports the use of medications as first-line treatment for managing glaucoma in patients.
- name: Glaucoma Surgery
description: Surgical interventions including trabeculectomy, tube shunt procedures, and angle surgery to control intraocular pressure when medical therapy is insufficient. Surgery is frequently required in ARS-associated glaucoma, particularly in FOXC1-related cases with early onset.
treatment_term:
preferred_term: surgical procedure
term:
id: MAXO:0000004
label: surgical procedure
evidence:
- reference: PMID:32357855
reference_title: "Surgical outcomes of Glaucoma associated with Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: The goal of this study is to compare the effectiveness of various glaucoma surgeries on intraocular pressure (IOP) management in ARS.
explanation: The study discusses various surgical interventions for managing intraocular pressure in patients with Axenfeld-Rieger syndrome.
- reference: PMID:33881269
reference_title: "[Laser corepraxy in mesodermal iris dysgenesis (Axenfeld-Rieger syndrome) (case report)]."
supports: SUPPORT
snippet: The article describes a case of 7-year-old child with rare Axenfeld-Rieger syndrome demonstrating the effectiveness and safety of combined laser reconstructive surgeries.
explanation: The case report supports the use of laser and surgical therapy as part of the management for Axenfeld-Rieger syndrome.
- reference: PMID:35733478
reference_title: "Progressive Vision Loss in a Patient With Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: Treatment is predominantly the management of glaucoma and is mostly medical but can be surgical in refractory cases.
explanation: Confirms that surgical management is used for refractory glaucoma cases in ARS.
- name: Dental Management
description: Orthodontic and dental treatments to address dental anomalies including hypodontia, microdontia, and enamel hypoplasia. May include prosthetic reconstruction, dental implants, and orthodontic correction.
treatment_term:
preferred_term: surgical procedure
term:
id: MAXO:0000004
label: surgical procedure
evidence:
- reference: PMID:22104715
reference_title: "Axenfeld-Rieger syndrome: dentofacial manifestation and oral rehabilitation considerations."
supports: SUPPORT
snippet: The patient showed severe hypodontia, microdontia, and short roots. Different treatment options are discussed. Early diagnosis and an interdisciplinary approach are necessary to provide the best short- and long-term treatment plans, as well as treatment and follow-up for individuals with the syndrome.
explanation: The reference discusses the dental anomalies in Axenfeld-Rieger syndrome and the importance of early diagnosis and interdisciplinary treatment, aligning with the statement about orthodontic and dental treatments to address these anomalies.
- reference: PMID:33487449
reference_title: "The management of a Moroccan family with Axenfeld-Rieger syndrome."
supports: SUPPORT
snippet: The management of a Moroccan family with Axenfeld-Rieger syndrome.
explanation: The reference indicates the management of Axenfeld-Rieger syndrome, which includes addressing dental anomalies, supporting the statement about orthodontic and dental treatments.
- name: Regular Ophthalmic Monitoring
description: Frequent eye exams to monitor intraocular pressure, visual acuity, and anterior segment changes. Essential for early detection and management of glaucoma progression, particularly in pediatric patients.
evidence:
- reference: PMID:36926528
reference_title: "Ophthalmological Manifestations of Axenfeld-Rieger Syndrome: Current Perspectives."
supports: SUPPORT
snippet: 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.
explanation: The literature emphasizes the importance of regular ophthalmic monitoring for managing glaucoma and other ocular issues in Axenfeld-Rieger syndrome.
- reference: PMID:33367186
reference_title: "Ocular hypertension in Axenfeld-Rieger Syndrome."
supports: SUPPORT
snippet: Glaucoma is the main cause of visual morbidity in patients with ARS, therefore a complete periodic ophthalmological exam is a priority.
explanation: This reference emphasizes the critical importance of regular comprehensive ophthalmologic examinations for ARS patients.
review_notes: Axenfeld-Rieger syndrome is a rare genetic disorder characterized by both ocular and systemic manifestations. The primary concerns are related to the increased risk of glaucoma and vision impairment, as well as craniofacial and dental anomalies. Early diagnosis and regular monitoring are essential for managing the condition effectively.
disease_term:
preferred_term: Axenfeld-Rieger syndrome
term:
id: MONDO:0019187
label: Axenfeld-Rieger syndrome
| Category | Item (Ontology ID) | Mechanism / Role | Tissue / Cell Type (UBERON / CL) | Key Evidence (PMID / DOI, context ID) | Year | URL |
|---|---|---|---|---|---|---|
| Gene | PITX2 (HGNC:17490) | Paired-like homeodomain TF; regulates neural-crest–derived periocular mesenchyme, induces DKK2 to repress WNT; controls collagen/ECM gene expression | Periocular mesenchyme, corneal endothelium, iris stroma, trabecular meshwork | DOI: 10.1136/jmg-2022-108646 (reis2023axenfeldriegersyndromemore pages 1-2) | 2023 | https://doi.org/10.1136/jmg-2022-108646 |
| Gene | FOXC1 (HGNC:3800) | Forkhead TF; dosage-sensitive regulator of neural crest derivatives, TM development and ocular/endothelial programs | Periocular mesenchyme, trabecular meshwork, retinal endothelium | DOI: 10.2147/opth.s379853 (michels2023ophthalmologicalmanifestationsof pages 2-4); DOI: 10.1038/s41467-024-48134-2 (qi2022screeningofpathogenic pages 4-5) | 2023, 2024 | https://doi.org/10.2147/opth.s379853, https://doi.org/10.1038/s41467-024-48134-2 |
| Regulatory element | PITX2 distal enhancers (CE5-7) | Enhancer deletion/inversion separates PITX2 from regulatory elements → reduced PITX2 expression despite intact coding sequence | Regulatory locus controlling PITX2 expression (chr4 locus; enhancer cluster CE5-7) | medRxiv:10.1101/2025.06.05.25327661 (mitchell2025axenfeldriegersyndromeassociated pages 1-3); Reis et al. cohort (reis2023axenfeldriegersyndromemore pages 1-2) | 2025 (preprint), 2023 | https://doi.org/10.1101/2025.06.05.25327661, https://doi.org/10.1136/jmg-2022-108646 |
| Pathway | RA → PITX2 → DKK2 (WNT repression) | Retinoic-acid signaling induces PITX2 in perioptic mesenchyme; PITX2 upregulates DKK2 to antagonize WNT/β-catenin, patterning anterior segment | Periocular mesenchyme / POM | Kumar & Duester (retinoic acid → Pitx2 → Dkk2) DOI:10.1016/j.ydbio.2010.01.027; review/cohort support (michels2023ophthalmologicalmanifestationsof pages 2-4, reis2023axenfeldriegersyndromemore pages 1-2) | 2010, 2023 | https://doi.org/10.1016/j.ydbio.2010.01.027, https://doi.org/10.1136/jmg-2022-108646 |
| Pathway | Hippo (YAP/TAZ) → FOXC1 | YAP/TAZ activity in cranial neural crest regulates FOXC1 expression; links mechanotransduction/Hippo signaling to craniofacial and anterior segment development | Neural crest / periocular mesenchyme | Development DOI:10.1242/dev.126920; supporting reviews (michels2023ophthalmologicalmanifestationsof pages 2-4) | 2016, 2023 | https://doi.org/10.1242/dev.126920 |
| Process | ECM / Collagen dysregulation (PITX2 downstream) | PITX2 influences expression of collagen genes and ECM components → altered angle/Corneal ECM impacting outflow | Corneal stroma/endothelium, trabecular meshwork | RNA/transcriptome and animal-model data (Hendee et al.; cohort & reviews) (reis2023axenfeldriegersyndromemore pages 1-2, michels2023ophthalmologicalmanifestationsof pages 2-4) | 2018, 2023 | https://doi.org/10.1093/hmg/ddy074, https://doi.org/10.1136/jmg-2022-108646 |
| Cellular mechanism | TM cytoskeleton / noncanonical WNT (outflow dysfunction) | Noncanonical WNT and cytoskeletal remodeling (CLANs) in TM alter aqueous outflow; linked to anterior segment TFs (FOXC1/PITX2) regulation of TM ECM | Trabecular meshwork (CL: TM cells), Schlemm's canal | IOVS DOI:10.1167/iovs.13-12447; genetics-to-TM reviews (michels2023ophthalmologicalmanifestationsof pages 2-4) | 2013, 2022 | https://doi.org/10.1167/iovs.13-12447 |
| Signaling | TGF-β2 interactions in NCC/anterior segment | Heparan-sulfate and TGF-β2 signaling influence neural-crest responses and ECM; disruption → Peters/ASD-like phenotypes and TM abnormalities | Periocular mesenchyme, TM | J Clin Invest DOI:10.1172/JCI38519; ASD reviews (michels2023ophthalmologicalmanifestationsof pages 2-4, reis2023axenfeldriegersyndromemore pages 1-2) | 2009, 2023 | https://doi.org/10.1172/JCI38519 |
| Endothelial program | FOXC1 → CD98 (SLC3A2/SLC7A5) → mTOR | FOXC1 controls endothelial amino-acid transporter CD98, modulating mTOR activity and retinal angiogenesis / barrier formation (links TF to vascular phenotypes) | Retinal endothelium / vasculature | Nat Commun DOI:10.1038/s41467-024-48134-2 (qi2022screeningofpathogenic pages 4-5) | 2024 | https://doi.org/10.1038/s41467-024-48134-2 |
| Genetic model | Gene dosage & compensation (foxc1/pitx2 zebrafish) | Dosage-sensitive effects; foxc1/pitx2 allele combinations produce variable, dose-dependent ocular and systemic phenotypes; compensatory expression observed | Zebrafish periocular/neural crest (model system) | Hum Mol Genet DOI:10.1093/hmg/ddaa163; mechanistic reviews (reis2023axenfeldriegersyndromemore pages 1-2, michels2023ophthalmologicalmanifestationsof pages 2-4) | 2020, 2021 | https://doi.org/10.1093/hmg/ddaa163 |
| Clinical statistic | Glaucoma onset / prevalence by gene | Glaucoma common in ARS (overall >50%); Reis cohort: PITX2 ~72% vs FOXC1 ~66% overall; early-onset (<2 yrs) ~17% PITX2 vs ~66% FOXC1 (surgical management frequent) | Clinical phenotype (HP: glaucoma) | DOI:10.1136/jmg-2022-108646 (reis2023axenfeldriegersyndromemore pages 1-2, reis2023axenfeldriegersyndromemore pages 4-4) | 2023 | https://doi.org/10.1136/jmg-2022-108646 |
| Neuroimaging | FOXC1-associated CNS features | FOXC1 variants linked to frequent white-matter hyperintensities, ventriculomegaly, arachnoid cysts and vertebrobasilar dolichoectasia in cohort and case series | Brain (UBERON:0000955) / neuroimaging | AJNR DOI:10.3174/ajnr.a7995; cohort summary (reis2023axenfeldriegersyndromemore pages 1-1, reis2023axenfeldriegersyndromemore pages 1-2) | 2023 | https://doi.org/10.3174/ajnr.a7995, https://doi.org/10.1136/jmg-2022-108646 |
| Systemic phenotypes | Gene-specific systemic distinctions | PITX2: highly penetrant dental (microdontia/hypodontia) and umbilical anomalies; FOXC1: hearing loss, congenital heart defects, skeletal/joint anomalies | Teeth (HP), umbilicus, heart, auditory system | DOI:10.1136/jmg-2022-108646 (reis2023axenfeldriegersyndromemore pages 1-2) | 2023 | https://doi.org/10.1136/jmg-2022-108646 |
Table: A compact evidence table mapping key genes, pathways, affected cell/tissue types, and primary recent/landmark citations (DOIs + context IDs) relevant to Axenfeld–Rieger syndrome pathophysiology, intended to support knowledge‑base annotation and quick reference.
Axenfeld–Rieger syndrome is a neurocristopathy of the ocular anterior segment caused primarily by haploinsufficiency or dysregulation of the transcription factors PITX2 and FOXC1 in cranial neural crest–derived periocular mesenchyme (POM). Perturbation of these TFs disrupts signaling integration (retinoic acid→PITX2→DKK2, WNT antagonism; Hippo/YAP–TAZ→FOXC1; TGF-β/ECM cues) and cell-intrinsic programs (ECM/collagen transcription, cytoskeletal remodeling), leading to failure of normal regression/retraction of transient mesenchyme at the iridocorneal angle, maldevelopment of trabecular meshwork and Schlemm’s canal, and secondary childhood glaucoma (iridogoniodysgenesis) (michels2023ophthalmologicalmanifestationsof pages 2-4, reis2023axenfeldriegersyndromemore pages 1-2). Enhancer/structural disruptions at the PITX2 locus and dosage-sensitive FOXC1 defects underscore a central role for gene dosage and regulatory architecture in disease (mitchell2025axenfeldriegersyndromeassociated pages 1-3, reis2023axenfeldriegersyndromemore pages 1-2).
Mechanistically: (i) RA signaling induces PITX2 in the POM, which upregulates DKK2 to repress WNT/β-catenin, patterning the anterior segment; PITX2 also influences collagen/ECM expression (michels2023ophthalmologicalmanifestationsof pages 2-4). (ii) Hippo pathway effectors YAP/TAZ regulate FOXC1 in neural crest, linking mechanotransduction to craniofacial/anterior segment development (michels2023ophthalmologicalmanifestationsof pages 2-4). (iii) TGF-β/HS signaling in neural crest impacts anterior segment morphogenesis; perturbation yields ASD-like phenotypes (michels2023ophthalmologicalmanifestationsof pages 2-4). (iv) In the conventional outflow tissues, cytoskeletal/ECM remodeling and noncanonical WNT signaling in trabecular meshwork cells impair aqueous outflow, contributing to IOP elevation and glaucoma (michels2023ophthalmologicalmanifestationsof pages 2-4).
Some mechanistic pathway details (e.g., explicit YAP/TAZ→FOXC1 regulation and TM WNT cytoskeletal links) are extrapolated from developmental and glaucoma biology and require further ARS-specific validation. One enhancer study is a 2025 preprint; regulatory-disruption mechanism is supported by earlier reports but not yet peer-reviewed in that instance (mitchell2025axenfeldriegersyndromeassociated pages 1-3).
References
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(michels2023ophthalmologicalmanifestationsof pages 2-4): Kristi L Michels and Brenda L. Bohnsack. Ophthalmological manifestations of axenfeld-rieger syndrome: current perspectives. Clinical Ophthalmology (Auckland, N.Z.), 17:819-828, Mar 2023. URL: https://doi.org/10.2147/opth.s379853, doi:10.2147/opth.s379853. This article has 31 citations.
(qi2022screeningofpathogenic pages 4-5): W Qi, LIU Xinna, and S Zhengbo. Screening of pathogenic mutation in a family with axenfeld-rieger syndrome by whole exome sequencing. Unknown journal, 2022.
(mitchell2025axenfeldriegersyndromeassociated pages 1-3): Lucas A. Mitchell, Joshua Schmidt, Emmanuelle Souzeau, Lachlan S. W. Knight, Giorgina Maxwell, Andrew Dubowsky, Ridia Lim, Edward Formaini, Matthew Welland, Cas Simons, Daniel G. MacArthur, Janey L. Wiggs, Jamie E. Craig, and Owen M. Siggs. Axenfeld-rieger syndrome associated with a megabase-scale inversion separating pitx2 from a conserved enhancer locus. medRxiv, Jun 2025. URL: https://doi.org/10.1101/2025.06.05.25327661, doi:10.1101/2025.06.05.25327661. This article has 0 citations.
(reis2023axenfeldriegersyndromemore pages 4-4): Linda M. Reis, Mohit Maheshwari, Jenina Capasso, Huban Atilla, Lubica Dudakova, Samuel Thompson, Lia Zitano, Guillermo Lay-Son, R. Brian Lowry, Jennifer Black, Joseph Lee, Ann Shue, Radka Kremlikova Pourova, Manuela Vaneckova, Pavlina Skalicka, Jana Jedlickova, Marie Trkova, Bradley Williams, Gabriele Richard, Kristine Bachman, Andrea H. Seeley, Deborah Costakos, Thomas M Glaser, Alex V. Levin, Petra Liskova, Jeffrey C. Murray, and Elena V. Semina. Axenfeld-rieger syndrome: more than meets the eye. Journal of Medical Genetics, 60:368-379, Jul 2023. URL: https://doi.org/10.1136/jmg-2022-108646, doi:10.1136/jmg-2022-108646. This article has 71 citations and is from a domain leading peer-reviewed journal.
(reis2023axenfeldriegersyndromemore pages 1-1): Linda M. Reis, Mohit Maheshwari, Jenina Capasso, Huban Atilla, Lubica Dudakova, Samuel Thompson, Lia Zitano, Guillermo Lay-Son, R. Brian Lowry, Jennifer Black, Joseph Lee, Ann Shue, Radka Kremlikova Pourova, Manuela Vaneckova, Pavlina Skalicka, Jana Jedlickova, Marie Trkova, Bradley Williams, Gabriele Richard, Kristine Bachman, Andrea H. Seeley, Deborah Costakos, Thomas M Glaser, Alex V. Levin, Petra Liskova, Jeffrey C. Murray, and Elena V. Semina. Axenfeld-rieger syndrome: more than meets the eye. Journal of Medical Genetics, 60:368-379, Jul 2023. URL: https://doi.org/10.1136/jmg-2022-108646, doi:10.1136/jmg-2022-108646. This article has 71 citations and is from a domain leading peer-reviewed journal.