Head and Neck Muscles
Eve K. Boyle, Vondel S. E. Mahon, Rui Diogo in Handbook of Muscle Variations and Anomalies in Humans, 2022
Inferior rectus muscles were thinner than normal in fetuses with anencephaly (Plock et al. 2007) and in a fetus with trisomy 18 and cyclopia (Smith et al. 2015). In a fetus with prosencephaly, there was a tripartite inferior rectus (von Lüdinghausen et al. 1999). Its lateral belly blended with the posterior tendon of inferior oblique and its medial belly attached medial to the main belly of inferior rectus (von Lüdinghausen et al. 1999). In two fetuses with triploidy, the attachments of the recti onto the sclera were shifted posteriorly (Moen et al. 1984). Diamond et al. (1980) noted the absence of the right inferior rectus in a child with craniofacial dysostosis. In a child with Axenfeld-Rieger syndrome, there was hypoplasia of inferior rectus on the right side (Bhate and Martin 2012).
Ophthalmology
Stephan Strobel, Lewis Spitz, Stephen D. Marks in Great Ormond Street Handbook of Paediatrics, 2019
Ocular associations include glaucoma, cataract, Axenfeld–Rieger syndrome, aniridia, microphthalmia, persistent hyperplastic primary vitreous (PHPV) and retinal dysplasia. Systemic abnormalities include craniofacial anomalies, central nervous system abnormalities, fetal alcohol syndrome, chromosomal abnormalities andPeters plus syndrome (a rare autosomal recessive disorder comprising short-limbed dwarfism, cleft lip and/or palate, brachydactyly and learning difficulties).
A de novo mutation in PITX2 underlies a unique form of Axenfeld-Rieger syndrome with corneal neovascularization and extensive proliferative vitreoretinopathy
Published in Ophthalmic Genetics, 2020
Stephanie N. Kletke, Ajoy Vincent, Jason T. Maynes, Uri Elbaz, Kamiar Mireskandari, Wai-Ching Lam, Asim Ali
Axenfeld-Rieger syndrome (ARS; OMIM #180500) is an autosomal dominant disorder characterized by a spectrum of anterior segment dysgenesis including posterior embryotoxon, iris hypoplasia, corectopia, polycoria, iridocorneal adhesions, and an associated 50% risk of glaucoma (1,2). Systemic features include facial anomalies such as maxillary hypoplasia, hypertelorism and telecanthus, dental, pituitary and cardiac abnormalities, as well as redundant periumbilical skin (1,2). ARS occurs secondary to developmental disruption of neural crest-derived tissues. Mutations in several genetic loci have been implicated, most notably in the transcription factor genes PITX2 and FOXC1 (3–12). PITX2, located at 4q25, encodes a paired-bicoid homeodomain transcriptional regulator that is expressed during ocular development (3,4,13,14).
Congenital cavitary optic disc anomaly and Axenfeld’s anomaly in Wolf-Hirschhorn syndrome: A case report and review of the literature
Published in Ophthalmic Genetics, 2018
Mohsin H. Ali, Nathalie F. Azar, Vinay Aakalu, Felix Y. Chau, Javaneh Abbasian, Pete Setabutr, Irene H. Maumenee
Microarray analysis using a comparative genomic hybridization and single nucleotide polymorphism (SNP) array revealed an unbalanced translocation between 4p16.3–15.3 (involving the deletion of 20.55 Mb and 387 genes) and Xp22.33-p22.2 (involving the duplication of 16.07 Mb and 186 genes). Several important deleted genes that are hypothesized to be integral to the pathogenesis of Wolf-Hirschhorn syndrome were involved, including WHSC1, NELFA (WHSC2), and LETM1(2). Chromosomal loci that have reported associations with Axenfeld-Rieger syndrome or related anterior segment dysgenesis phenotypes were not affected. The constellation of clinical findings and the genetic analysis confirmed the diagnosis of Wolf-Hirschhorn syndrome.
Mutation Survey of Candidate Genes and Genotype–Phenotype Analysis in 20 Southeastern Chinese Patients with Axenfeld–Rieger Syndrome
Published in Current Eye Research, 2018
Xun Wang, Xing Liu, Liqin Huang, Shaohua Fang, Xiaoyun Jia, Xueshan Xiao, Shiqiang Li, Xiangming Guo
Axenfeld–Rieger syndrome (ARS; OMIM 180500, 601499, 602482) is an autosomal dominant disease with anterior segment dysgenesis. Major ocular abnormalities associated with this disease include iris stromal hypoplasia, iridocorneal adhesion, corectopia, polycoria, and posterior embryotoxon. Systemic anomalies associated with ARS include facial malformation (telecanthus, maxillary hypoplasia, and flattening of the midface), dental abnormalities (microdontia, oligodontia, hypodontia, and adontia), and redundant periumbilical skin.1,2 Other uncommon systemic features include congenital heart disease, hearing loss, and growth retardation.1,3 Its most severe threat to vision is glaucoma secondary to the maldevelopment of aqueous humor drainage structures.2 It is estimated that the incidence of glaucoma in patients with ARS is as high as 50%.1,4 In ARS, glaucoma onset mainly occurs before the patient becomes a teenager. In one study, the median age at glaucoma diagnosis in 53 patients with ARS was 13.5 years old, and its penetrance in 10-year-olds was 29.4%.3 When glaucoma occurs, affected children are unable to describe their illness accurately or in a timely manner. Early onset glaucoma is associated with a high incidence of blindness and greatly affects the quality of life of patients and their families. Early genetic diagnosis can help identify patients with an elevated risk of developing glaucoma and encourage more regular ophthalmic examinations and treatment. Studies that assess the genotype–phenotype relationship in ARS and those that perform earlier mutation surveys of candidate genes can improve the accuracy of prognoses and provide a higher quality of life for these patients.
Related Knowledge Centers
- Autosome
- Dominance
- Iris Hypoplasia With Glaucoma
- Corectopia
- Polycoria
- Molecular Genetics
- Glaucoma
- Pitx2
- Schwalbe'S Line
- Forkhead Box C1