1
|
Sun J, Zhu X, Zhao Y, Zhou Q, Qi R, Liu H. CHN1 is a Novel Prognostic Marker for Diffuse Large B-Cell Lymphoma. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2021; 14:397-408. [PMID: 33833551 PMCID: PMC8021264 DOI: 10.2147/pgpm.s301718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/15/2021] [Indexed: 12/14/2022]
Abstract
Purpose Diffuse large B-cell lymphoma (DLBCL) is the most common B-cell malignancy. Thirty to forty percent of DLBCL patients still experience relapse or develop refractory disease even with standard immunochemotherapy, leading to a poor prognosis. Currently, although several gene-based classification methods can be used to predict the prognosis of DLBCL, some patients are still unable to be classified. This study was performed to identify a novel prognostic biomarker for DLBCL. Patients and Methods A total of 1850 B-cell non-Hodgkin lymphoma (B-NHL) patients in 8 independent datasets with microarray gene expression profiles were retrieved from the Gene Expression Omnibus (GEO) database and Lymphoma/Leukemia Molecular Profiling Project (LLMPP). The candidate genes were selected through three filters in a strict pipeline. Survival analysis was performed in two independent datasets of patients with both gene expression data and clinical information. Gene set enrichment analysis (GSEA) and the CIBERSORT algorithm were used to explore the biological functions of the genes. Results We identified 6 candidate genes associated with the clinical outcome of DLBCL patients: CHN1, CD3D, CLU, ICOS, KLRB1 and LAT. Unlike the other five genes, CHN1 has not been previously reported to be implicated in lymphoma. We also observed that CHN1 had prognostic significance in important clinical subgroups; in particular, high CHN1 expression was significantly related to good outcomes in DLBCL patients with the germinal center B-cell-like (GCB) subtype, stage III–IV, or an International Prognostic Index (IPI) score > 2. Multivariate Cox regression analysis of the two datasets showed that CHN1 was an independent prognostic factor for DLBCL. Additionally, GSEA and CIBERSORT indicated that CHN1 was correlated with cell adhesion and T cell immune infiltration. Conclusion Our data indicate for the first time that high CHN1 expression is associated with favorable outcomes in DLBCL patients, suggesting its potential utility as a prognostic marker in DLBCL.
Collapse
Affiliation(s)
- Jie Sun
- Department of Hematology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Xiaoquan Zhu
- The Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Yanyang Zhao
- The Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Qi Zhou
- The Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Ruomei Qi
- The Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Hui Liu
- Department of Hematology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| |
Collapse
|
2
|
Pavone P, Cho SY, Praticò A, Falsaperla R, Ruggieri M, Jin DK. Ptosis in childhood: A clinical sign of several disorders: Case series reports and literature review. Medicine (Baltimore) 2018; 97:e12124. [PMID: 30200099 PMCID: PMC6133583 DOI: 10.1097/md.0000000000012124] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Blepharoptosis (ptosis) is a common but often overlooked sign that may serve as a sign/manifestation of other conditions, ranging from a mild and purely cosmetic presentation to a severe and occasionally progressive disorder. Ptosis may show an acute onset or may manifest as a chronic disorder. Its presentation may vary: unilateral versus bilateral, progressive versus non-progressive, isolated versus complex which occurs in association with other symptoms, and congenital versus acquired (often concomitant with neuromuscular disorders).Congenital ptosis includes the isolated type-the congenital cranial dysinnervation disorders, which are further, distinguished into different subtypes such as Horner syndrome (HS), and ptosis as a sign/manifestation of various congenital malformation syndromes.In this article, we review the primary causes of ptosis occurring in childhood, and its various clinical presentations, including a short report on selected cases observed in our institution: a classical isolated familial ptosis comprising 14 members over 5 generations, 3 sibling with isolated congenital ptosis who in addition suffered by episodes of febrile seizures, a patient with Duane retraction syndrome who presented congenital skin and hair anomalies, and a girl with HS who showed a history of congenital imperforate hymen. A flowchart outlining the congenital and acquired type of ptosis and the clinical approach to the management and treatment of children with this anomaly is reported.
Collapse
Affiliation(s)
- P. Pavone
- University-Hospital Policlinico-Vittorio Emanuele
| | - Sung Yoon Cho
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - A.D. Praticò
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Italy
| | | | - M. Ruggieri
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Italy
| | - Dong-Kyu Jin
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| |
Collapse
|
3
|
Biler ED, Ilim O, Onay H, Uretmen O. CHN1 gene mutation analysis in patients with Duane retraction syndrome. J AAPOS 2017; 21:472-475.e2. [PMID: 29031989 DOI: 10.1016/j.jaapos.2017.07.208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 07/10/2017] [Accepted: 07/20/2017] [Indexed: 01/17/2023]
Abstract
PURPOSE To investigate CHN1 (chimerin 1) gene mutations in patients with isolated nonsyndromic Duane syndrome and accompanying positive familial history, bilaterality, or various systemic disorders. METHODS Patients with Duane retraction syndrome (DRS) and a positive family history of congenital ocular motility disturbance or bilateral involvement or accompanying any congenital disorder(s) seen consecutively at a single center from 2013 to 2016 were enrolled. All subjects underwent full ophthalmologic examination, including refraction, best-corrected visual acuity, ocular alignment and motility, globe retraction, and biomicroscopic or fundus evaluation. DNA samples were investigated by direct sequencing of the coding regions of the CHN1 gene. RESULTS A total of 30 patients (15 males) were included (mean age, 11.8 ± 10.4 years; range, 2-45 years): 8 cases presented with bilateral DRS; 22, with unilateral DRS. Family history of ocular motility abnormality was positive in 16 patients. Eleven cases had an additional congenital disorder. In 2 patients, 2 different mutations were detected in the CHN1 gene: p.E313K (c.937G>A) and p.N224S (c.671A>G). CONCLUSIONS CHN1 mutations were identified in 2 bilateral cases and in 1 parent of 1 affected case. One mutation is novel and occurred with additional vertical gaze abnormalities. Additional genetic studies evaluating chimerin 1 (CHN1) and its role in the development of the ocular motor axis are needed to provide new data about these mutations and phenotypic variations.
Collapse
Affiliation(s)
| | - Orhan Ilim
- Department of Ophthalmology, Ege University Faculty of Medicine, Izmir, Turkey
| | - Huseyin Onay
- Department of Molecular Genetics, Ege University Faculty of Medicine, Izmir, Turkey
| | - Onder Uretmen
- Department of Ophthalmology, Ege University Faculty of Medicine, Izmir, Turkey
| |
Collapse
|
4
|
Mari L, Blacklock BT, Stavinohova R, De Risio L. Extraocular muscle dysinnervation disorder resembling Duane retraction syndrome in a 9-month-old French Bulldog. Vet Ophthalmol 2017; 20:472-476. [DOI: 10.1111/vop.12396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Lorenzo Mari
- Neurology/Neurosurgery Service; Centre for Small Animal Studies; Animal Health Trust; Newmarket UK
| | - Benjamin T. Blacklock
- Ophthalmology Service; Centre for Small Animal Studies; Animal Health Trust; Newmarket UK
| | - Renata Stavinohova
- Ophthalmology Service; Centre for Small Animal Studies; Animal Health Trust; Newmarket UK
| | - Luisa De Risio
- Neurology/Neurosurgery Service; Centre for Small Animal Studies; Animal Health Trust; Newmarket UK
| |
Collapse
|
5
|
Marenco M, Macchi I, Macchi I, Galassi E, Massaro-Giordano M, Lambiase A. Clinical presentation and management of congenital ptosis. Clin Ophthalmol 2017; 11:453-463. [PMID: 28280295 PMCID: PMC5338973 DOI: 10.2147/opth.s111118] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Congenital ptosis is a rare condition characterized by lower positioning of the upper eyelid that is present at birth and is a clinical condition that is persistent if not treated. It may be unilateral or bilateral and may be associated with other ocular disorders or systemic conditions, including Marcus Gunn, Horner, and Duane syndromes. It is a benign condition but causes functional, cosmetic, and psychological problems in children. However, not all patients need to undergo surgery, and usually only patients at risk of amblyopia need a prompt surgical correction, while in other cases, surgery can be postponed. The grade of ptosis, the eyelid function, and the amblyopic risk are the parameters that affect the ophthalmologist’s decision on timing of surgery and the surgical technique to be used. In fact, there are several types of surgical techniques to correct a congenital ptosis, although very often more than one is needed to obtain an acceptable result. This paper reviews the causes of congenital ptosis and associated diseases. Particular emphasis is given to surgical management and different procedures available to correct the upper eyelid anomaly and avoid permanent damage to visual function.
Collapse
Affiliation(s)
- Marco Marenco
- Department of Sense Organs, University of Rome "Sapienza"
| | - Ilaria Macchi
- Department of Ophthalmology, Campus Bio-Medico University of Rome, Rome
| | - Iacopo Macchi
- Department of Ophthalmology, University of Catania, Catania
| | - Emilio Galassi
- Ophthalmic Clinic, Department of Ophthalmology, University of L'Aquila, L'Aquila, Italy
| | - Mina Massaro-Giordano
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | | |
Collapse
|
6
|
Congenital cranial dysinnervation disorders. Int Ophthalmol 2016; 37:1369-1381. [PMID: 27837354 DOI: 10.1007/s10792-016-0388-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/31/2016] [Indexed: 12/13/2022]
Abstract
The European Neuromuscular Centre (ENMC) derived the term Congenital Cranial Dysinnervation Disorders in 2002 at an international workshop for a group of congenital neuromuscular diseases. CCDDs are congenital, non-progressive ophthalmoplegia with restriction of globe movement in one or more fields of gaze. This group of sporadic and familial strabismus syndromes was initially referred to as the 'congenital fibrosis syndromes' because it was assumed that the primary pathologic process starts in the muscles of eye motility. Over the last few decades, evidence has accumulated to support that the primary pathologic process of these disorders is neuropathic rather than myopathic. This is believed that for normal development of extra ocular muscles and for preservation of muscle fiber anatomy, normal intra-uterine development of the innervation to these muscles is essential. Congenital dysinnervation to these EOMs can lead to abnormal muscle structure depending upon the stage and the extent of such innervational defects. Over last few years new genes responsible for CCDD have been identified, permitting a better understanding of associated phenotypes, which can further lead to better classification of these disorders. Introduction of high-resolution MRI has led to detailed study of cranial nerves courses and muscles supplied by them. Thus, due to better understanding of pathophysiology and genetics of CCDDs, various treatment modalities can be developed to ensure good ocular alignment and better quality of life for patients suffering from the same.
Collapse
|
7
|
|
8
|
Graeber CP, Hunter DG, Engle EC. The genetic basis of incomitant strabismus: consolidation of the current knowledge of the genetic foundations of disease. Semin Ophthalmol 2014; 28:427-37. [PMID: 24138051 DOI: 10.3109/08820538.2013.825288] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In recent years, our understanding of the genetic foundations of incomitant strabismus has grown significantly. Much new understanding has been gleaned since the concept of congenital cranial dysinnervation disorders (CCDDs) was introduced in 2002, and the genetic basis of CCDDs continues to be elucidated. In this review, we aim to provide an update of the genetic and clinical presentation of these disorders. Disorders reviewed include Duane syndrome (DS), HOXA1 and HOXB1 syndromes, Moebius syndrome, congenital fibrosis of the extraocular muscles (CFEOM), and horizontal gaze palsy with progressive scoliosis (HGPPS).
Collapse
|
9
|
Duane syndrome in the setting of chromosomal duplications. Am J Ophthalmol 2010; 150:932-8. [PMID: 20933218 DOI: 10.1016/j.ajo.2010.06.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 06/19/2010] [Accepted: 06/22/2010] [Indexed: 01/24/2023]
Abstract
PURPOSE To describe the clinical findings in 3 patients with Duane syndrome and 3 different chromosomal duplications that may indicate the location of genes involved in the pathogenesis of this ocular motility disorder. DESIGN Observational case series. METHODS setting: Clinical practice. patient or study population: Three patients with Duane syndrome and chromosomal duplications from the clinical practice of 1 of the authors. observation procedures: Chart review and retrieval of clinical data and results of pertinent clinical tests, in this case chromosomal studies. main outcome measure: Reporting of details of clinical findings and duplicated chromosomal regions. RESULTS Two patients had unilateral type I Duane syndrome and 1 had bilateral type I Duane syndrome. Two had cognitive delay, and all 3 had other systemic abnormalities, including a variety of congenital malformations. The chromosomal abnormalities that were detected using microarray analysis were 2q13(RP11-20G1,RP11-461N11) × 3, 10q24.2q26.3(101,532,585-135,284, 169) × 3, 20q13.12(44,796,613-44,945, 818) × 3, and 22q11.1q11.22(RP11-701M12, RP11-71G19) × 3. CONCLUSIONS Patients with Duane syndrome and associated congenital malformations or developmental delay should be evaluated for the presence of underlying chromosomal duplications. The regions of chromosomes 2, 10, and 22 that we report may harbor genes involved in the pathogenesis of Duane syndrome.
Collapse
|
10
|
Review of the major findings about Duane retraction syndrome (DRS) leading to an updated form of classification. Vision Res 2010; 50:2334-47. [PMID: 20801148 DOI: 10.1016/j.visres.2010.08.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 08/13/2010] [Indexed: 11/20/2022]
Abstract
In view of all the reported evidence by electromyography in the 1970s, by histology in the 1980s, and by cerebral imagery since the 2000s, Duane retraction syndrome (DRS) has been described as the consequence of a congenital anomaly of the 6th cranial nerve nuclei with aberrant innervations by supply from the 3rd cranial nerve. Both genetic and environmental factors are likely to play a role when the cranial nerves and ocular muscles are developing between the 4th and the 8th week of gestation. New data from eye movement recordings contributed to better understanding the binocular control of saccades. Modeling of saccades in DRS seems promising for the quantification of the innervational deficit and the mechanical properties of the eye plant. The usual clinical classification of DRS needs to be updated in order to match more accurately the underlying dysinnervation of the extra ocular muscles and to illustrate the continuum that exists between the various forms. This review aims to summarize the major findings about DRS and to guide the clinician in the surgical management of this particular form of strabismus.
Collapse
|
11
|
Miyake N, Andrews C, Fan W, He W, Chan WM, Engle EC. CHN1 mutations are not a common cause of sporadic Duane's retraction syndrome. Am J Med Genet A 2010; 152A:215-7. [PMID: 20034095 DOI: 10.1002/ajmg.a.33168] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Noriko Miyake
- Department of Neurology, Children's Hospital Boston, Boston, Massachusetts, USA
| | | | | | | | | | | |
Collapse
|
12
|
Garnica-Hayashi RE, Vargas-Ortega J, Zenteno JC. Left-sided Duane's Syndrome and Retinal Coloboma associated with Contralateral Microphthalmia. Strabismus 2009; 15:113-7. [PMID: 17564942 DOI: 10.1080/09273970701431418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Case report of a 15-year-old girl presenting with a left-sided Duane's retraction syndrome (DURS) in combination with ipsilateral retinal coloboma and contralateral microphthalmia. Abduction limitation as well as narrowing of the palpebral fissure and globe retraction during attempted adduction (type I DURS) was demonstrated in the left eye. Additionally, a retinal coloboma was observed in the nasal inferior quadrant of the left eye. No other somatic or developmental abnormalities were observed and karyotypic analysis was normal. This is the first case of non-syndromic unilateral DURS associated with a contralateral major ocular malformation. This unusual clinical combination probably arose from the embryonic action of an eye-specific disruptor.
Collapse
Affiliation(s)
- Rosa E Garnica-Hayashi
- Department of Strabismus, Instituto de Oftalmología, Fundación Conde de Valenciana, Mexico City, Mexico
| | | | | |
Collapse
|
13
|
Murillo-Correa CE, Kon-Jara V, Engle EC, Zenteno JC. Clinical features associated with an I126M alpha2-chimaerin mutation in a family with autosomal-dominant Duane retraction syndrome. J AAPOS 2009; 13:245-8. [PMID: 19541263 PMCID: PMC2702258 DOI: 10.1016/j.jaapos.2009.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Revised: 03/10/2009] [Accepted: 03/19/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE We describe the clinical phenotype of a Mexican family segregating Duane syndrome as an autosomal-dominant trait linked to chromosome 2q31 (DURS2) and previously reported to harbor a heterozygous alpha2-chimaerin missense mutation. METHODS A 5-generation Mexican family was analyzed. Ten affected subjects were available for clinical examination. Participating subjects were tested for visual acuity, ocular alignment by prism cover testing, ocular ductions and versions, and globe retraction. In children, alignment was measured with the Krimsky test in cardinal positions of gaze. RESULTS Ten cases were included, 6 female and 4 male subjects. Five cases presented with bilateral and 5 with unilateral Duane syndrome. The right side was the most commonly affected side on unilateral cases. Five cases exhibited exotropia, 4 esotropia, and 1 hypotropia. Seven patients had severe limitation of abduction and two had moderate limitation. Four patients had mild adduction limitation and 4 had moderate limitation. No additional anomalies such as fourth (trochlear) nerve palsy, blepharoptosis, or dense amblyopia, which have been reported in previous families with Duane syndrome, were observed. All 3 cases that exhibited vertical dysfunction had upgaze limitation. One instance of nonpenetrance was recorded. CONCLUSIONS Considerable intrafamilial clinical variability was observed in this Duane syndrome pedigree that carried a alpha2-chimaerin mutation. The presence of bilateral involvement and associated vertical movements, which commonly are observed in this and other DURS2 families, could suggest the occurrence of CHN1 mutations as the source of the disease in isolated or familial DURS cases.
Collapse
|
14
|
Tischfield MA, Chan WM, Grunert JF, Andrews C, Engle EC. HOXA1 mutations are not a common cause of Duane anomaly. Am J Med Genet A 2009; 140:900-2. [PMID: 16528738 PMCID: PMC2553396 DOI: 10.1002/ajmg.a.31167] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
15
|
Miyake N, Chilton J, Psatha M, Cheng L, Andrews C, Chan WM, Law K, Crosier M, Lindsay S, Cheung M, Allen J, Gutowski NJ, Ellard S, Young E, Iannaccone A, Appukuttan B, Stout JT, Christiansen S, Ciccarelli ML, Baldi A, Campioni M, Zenteno JC, Davenport D, Mariani LE, Sahin M, Guthrie S, Engle EC. Human CHN1 mutations hyperactivate alpha2-chimaerin and cause Duane's retraction syndrome. Science 2008; 321:839-43. [PMID: 18653847 PMCID: PMC2593867 DOI: 10.1126/science.1156121] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Duane's retraction syndrome (DRS) is a complex congenital eye movement disorder caused by aberrant innervation of the extraocular muscles by axons of brainstem motor neurons. Studying families with a variant form of the disorder (DURS2-DRS), we have identified causative heterozygous missense mutations in CHN1, a gene on chromosome 2q31 that encodes alpha2-chimaerin, a Rac guanosine triphosphatase-activating protein (RacGAP) signaling protein previously implicated in the pathfinding of corticospinal axons in mice. We found that these are gain-of-function mutations that increase alpha2-chimaerin RacGAP activity in vitro. Several of the mutations appeared to enhance alpha2-chimaerin translocation to the cell membrane or enhance its ability to self-associate. Expression of mutant alpha2-chimaerin constructs in chick embryos resulted in failure of oculomotor axons to innervate their target extraocular muscles. We conclude that alpha2-chimaerin has a critical developmental function in ocular motor axon pathfinding.
Collapse
Affiliation(s)
- Noriko Miyake
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - John Chilton
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Research Way, Plymouth PL6 8BU, UK
| | - Maria Psatha
- MRC Centre for Developmental Neurobiology, King's College, Guy's Campus, London SE1 1UL, UK
| | - Long Cheng
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Caroline Andrews
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115, USA
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Wai-Man Chan
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115, USA
| | - Krystal Law
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115, USA
| | - Moira Crosier
- MRC-Wellcome Trust Human Developmental Biology Resource (Newcastle), Institute of Human Genetics, Newcastle University, International Centre for Life, Newcastle upon Tyne, NE1 3BZ, UK
| | - Susan Lindsay
- MRC-Wellcome Trust Human Developmental Biology Resource (Newcastle), Institute of Human Genetics, Newcastle University, International Centre for Life, Newcastle upon Tyne, NE1 3BZ, UK
| | - Michelle Cheung
- MRC Centre for Developmental Neurobiology, King's College, Guy's Campus, London SE1 1UL, UK
| | - James Allen
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Research Way, Plymouth PL6 8BU, UK
| | - Nick J Gutowski
- Department of Neurology, Royal Devon and Exeter Hospital, Barrack Road, Exeter, Devon, EX2 5DW, UK
- Peninsula Medical School, Barrack Road, Exeter EX2 5DW, UK
| | - Sian Ellard
- Department of Molecular Genetics, Royal Devon and Exeter Hospital, Barrack Road, Exeter, Devon, EX2 5DW, UK
- Peninsula Medical School, Barrack Road, Exeter EX2 5DW, UK
| | | | - Alessandro Iannaccone
- University of Tennessee Health Science Center, Hamilton Eye Institute, 930 Madison Avenue, Suite 731, Memphis, TN 38163, USA
| | - Binoy Appukuttan
- Casey Eye Institute, Oregon Health and Science University, 3375 SW Terwilliger Blvd, Portland, OR 97239, USA
| | - J. Timothy Stout
- Casey Eye Institute, Oregon Health and Science University, 3375 SW Terwilliger Blvd, Portland, OR 97239, USA
| | - Stephen Christiansen
- Department of Ophthalmology, University of Minnesota, MMC 493, 420 Delaware St, SE, Minneapolis, MN 55455-0501, USA
| | | | - Alfonso Baldi
- Department of Biochemistry 'F. Cedrangolo', Section of Pathologic Anatomy, Second University of Naples, Naples, Italy
| | - Mara Campioni
- Department of Biochemistry 'F. Cedrangolo', Section of Pathologic Anatomy, Second University of Naples, Naples, Italy
| | - Juan C. Zenteno
- Department of Genetics and Research Unit, Institute of Ophthalmology “Conde de Valenciana”, Mexico City, Mexico
| | - Dominic Davenport
- MRC Centre for Developmental Neurobiology, King's College, Guy's Campus, London SE1 1UL, UK
| | - Laura E. Mariani
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115, USA
| | - Mustafa Sahin
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Sarah Guthrie
- MRC Centre for Developmental Neurobiology, King's College, Guy's Campus, London SE1 1UL, UK
| | - Elizabeth C. Engle
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115, USA
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115, USA
- Department of Ophthalmology, Children’s Hospital Boston, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| |
Collapse
|
16
|
Abstract
Congenital cranial dysinnervation disorders (CCDDs) are responsible for 1-2% of infant strabismus cases. Insufficient innervation and misinnervation of aberrant nerve fibres lead to motility restrictions and synkinesis. We present the most common CCDDs and explain their pathogenesis and the resulting clinical features. Furthermore, we emphasize essential diagnostic steps and treatment aspects.
Collapse
Affiliation(s)
- C Pieh
- Universitätsaugenklinik Freiburg, Killianstrasse 5, 79106 Freiburg.
| | | |
Collapse
|
17
|
Demer JL, Clark RA, Lim KH, Engle EC. Magnetic resonance imaging of innervational and extraocular muscle abnormalities in Duane-radial ray syndrome. Invest Ophthalmol Vis Sci 2008; 48:5505-11. [PMID: 18055799 DOI: 10.1167/iovs.07-0772] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
PURPOSE The authors used magnetic resonance imaging (MRI) to study extraocular muscles (EOMs) and nerves in Duane-radial ray (Okihiro) syndrome (DRRS) caused by mutations in the transcription factor SALL4. METHODS The authors examined four male and two female affected members of a pedigree previously reported to cosegregate DRRS and a heterozygous SALL4 mutation. Coronal T1-weighted magnetic resonance images of the orbits and heavily T2-weighted images in the plane of the cranial nerves were obtained in four subjects. MRI findings were correlated with motility examinations and published norms obtained using identical technique. RESULTS Five of the six subjects with DRRS had radial ray abnormalities including thumb, radial artery, radial bone, and pectoral muscle hypoplasia. Three had bilateral and three had unilateral ocular involvement. Seven eyes had limitation of both abduction and adduction, whereas two had limitations only of abduction. Most affected eyes had lid fissure narrowing and retraction in adduction. Intraorbital and intracranial abducens nerves (CN6) were small to absent, particularly ipsilateral to abduction deficiency. All subjects undergoing MRI had normal intracranial oculomotor nerves (CN3). Optic nerve (ON) cross-section findings were similar to normal. EOMs and pulleys were structurally normal in most subjects. In some affected orbits, a branch of CN3 closely approximated and presumably innervated the LR. CONCLUSIONS DRRS encompasses a Duane syndrome phenotype, with a variable and asymmetric endophenotype including marked CN6 hypoplasia and probable innervation or coinnervation of the LR by CN3. This endophenotype is more limited than reported in DURS2-linked Duane syndrome (On-line Mendelian Inheritance in Man, OMIM 604356) and CFEOM1 (OMIM 135700), which are clinically similar congenital cranial dysinnervation disorders that also feature CN3 hypoplasia and more widespread EOM abnormalities.
Collapse
Affiliation(s)
- Joseph L Demer
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, CA 90095-7002, USA.
| | | | | | | |
Collapse
|
18
|
Bosley TM, Salih MA, Alorainy IA, Oystreck DT, Nester M, Abu-Amero KK, Tischfield MA, Engle EC. Clinical characterization of the HOXA1 syndrome BSAS variant. Neurology 2007; 69:1245-53. [PMID: 17875913 PMCID: PMC2826214 DOI: 10.1212/01.wnl.0000276947.59704.cf] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND The Bosley-Salih-Alorainy syndrome (BSAS) variant of the congenital human HOXA1 syndrome results from autosomal recessive truncating HOXA1 mutations. We describe the currently recognized spectrum of ocular motility, inner ear malformations, cerebrovascular anomalies, and cognitive function. METHODS We examined nine affected individuals from five consanguineous Saudi Arabian families, all of whom harbored the same I75-I76insG homozygous mutation in the HOXA1 gene. Patients underwent complete neurologic, neuro-ophthalmologic, orthoptic, and neuropsychological examinations. Six individuals had CT, and six had MRI of the head. RESULTS All nine individuals had bilateral Duane retraction syndrome (DRS) type 3, but extent of abduction and adduction varied between eyes and individuals. Eight patients were deaf with the common cavity deformity of the inner ear, while one patient had normal hearing and skull base development. Six had delayed motor milestones, and two had cognitive and behavioral abnormalities meeting Diagnostic and Statistical Manual of Mental Disorders-IV criteria for autism spectrum disorder. MRI of the orbits, extraocular muscles, brainstem, and supratentorial brain appeared normal. All six appropriately studied patients had cerebrovascular malformations ranging from unilateral internal carotid artery hypoplasia to bilateral agenesis. CONCLUSIONS This report extends the Bosley-Salih-Alorainy syndrome phenotype and documents the clinical variability resulting from identical HOXA1 mutations within an isolated ethnic population. Similarities between this syndrome and thalidomide embryopathy suggest that the teratogenic effects of early thalidomide exposure in humans may be due to interaction with the HOX cascade.
Collapse
Affiliation(s)
- T M Bosley
- Neuro-ophthalmology Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Engle EC, Andrews C, Law K, Demer JL. Two pedigrees segregating Duane's retraction syndrome as a dominant trait map to the DURS2 genetic locus. Invest Ophthalmol Vis Sci 2007; 48:189-93. [PMID: 17197532 PMCID: PMC2829295 DOI: 10.1167/iovs.06-0631] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PURPOSE The genetic bases of Duane's retraction syndrome (DRS) were investigated to determine its molecular etiologies. In prior studies, the transcription factors SALL4 and HOXA1 were identified as the genes mutated in DRS with radial anomalies, and in DRS with deafness, vascular anomalies, and cognitive deficits, respectively. Less is known, however, about the genetic etiology of DRS when it occurs in isolation, and only one genetic locus for isolated DRS, the DURS2 locus on chromosome 2, has been mapped to date. Toward the goal of identifying the DURS2 gene, two pedigrees have been ascertained that segregate DRS as a dominant trait. METHODS Members of two large dominant DRS pedigrees were enrolled in an ongoing study of the genetic basis of the congenital cranial dysinnervation disorders, and linkage analysis was conducted to determine whether their DRS phenotype maps to the DURS2 locus. RESULTS By haplotype analysis, the DRS phenotype in each family cosegregates with markers spanning the DURS2 region. Linkage analysis reveals maximum lod scores >2, establishing that the DRS phenotype in these two pedigrees maps to the DURS2 locus. CONCLUSIONS These two pedigrees double the published pedigrees known to map to the DURS2 locus and can thus contribute toward the search for the DURS2 gene. The affected members represent a genetically defined population of DURS2-linked DRS individuals, and hence studies of their clinical and structural features can enhance understanding of the DURS2 phenotype, as described in the companion paper.
Collapse
Affiliation(s)
- Elizabeth C Engle
- Program in Genomics, Children's Hospital, Boston, Massachusetts 02115, USA.
| | | | | | | |
Collapse
|
20
|
Demer JL, Clark RA, Lim KH, Engle EC. Magnetic resonance imaging evidence for widespread orbital dysinnervation in dominant Duane's retraction syndrome linked to the DURS2 locus. Invest Ophthalmol Vis Sci 2007; 48:194-202. [PMID: 17197533 PMCID: PMC1850629 DOI: 10.1167/iovs.06-0632] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE High-resolution, multipositional magnetic resonance imaging (MRI) was used to demonstrate extraocular muscles (EOMs) and associated motor nerves in Duane retraction syndrome (DRS) linked to the DURS2 locus on chromosome 2. METHODS Five male and three female affected members of two autosomal dominant DURS2 pedigrees were enrolled in the study. Coronal T(1)-weighted MRI of the orbits was obtained in multiple gaze positions, as well as with heavy T(2) weighting in the plane of the cranial nerves. MRI findings were correlated with motility. RESULTS All subjects had unilateral or bilateral limitation of abduction, or of both abduction and adduction, with palpebral fissure narrowing and globe retraction in adduction. Orbital motor nerves were typically small, with the abducens nerve (cranial nerve [CN]6) often nondetectable. Lateral rectus (LR) muscles were structurally abnormal in seven subjects, with structural and motility evidence of oculomotor nerve (CN3) innervation from vertical rectus EOMs leading to A or V patterns of strabismus in three cases. Four cases had superior oblique, two cases superior rectus, and one case levator EOM hypoplasia. Only the medial and inferior rectus and inferior oblique EOMs were spared. Two cases had small CN3s. CONCLUSIONS DRS linked to the DURS2 locus is associated with bilateral abnormalities of many orbital motor nerves, and structural abnormalities of all EOMs except those innervated by the inferior division of CN3. The LR may be coinnervated by CN3 branches normally destined for any other rectus EOMs. Therefore, DURS2-linked DRS is a diffuse congenital cranial dysinnervation disorder involving but not limited to CN6.
Collapse
Affiliation(s)
- Joseph L Demer
- Department of Ophthalmology, UCLA, Los Angeles, CA 90095-7002, USA.
| | | | | | | |
Collapse
|
21
|
Kato Z, Yamagishi A, Kondo N. Interstitial deletion of 1q42.13-q43 with Duane retraction syndrome. J AAPOS 2007; 11:62-4. [PMID: 17126050 DOI: 10.1016/j.jaapos.2006.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 09/04/2006] [Accepted: 09/05/2006] [Indexed: 11/26/2022]
Abstract
Duane retraction syndrome is a congenital eye movement disorder characterized by failure of the sixth cranial nerve or nucleus to develop properly, resulting in restriction of abduction, narrowing of the palpebral fissure, and retraction of the globe on attempted adduction and/or restricted adduction. The gene loci of Duane syndrome have been mapped on 8q and 2q, indicating a heterogeneity. We report here a patient with interstitial deletion of 1q with Duane syndrome. The karyotype of our patient suggests another possible locus of the Duane syndrome, and the mapped genes around the deleted region, 1q42.13-43, contain possible candidate genes such as a homeobox gene. However, further clinical descriptions of patients with Duane syndrome and genetic investigations of the deleted regions are needed for a more accurate delineation.
Collapse
Affiliation(s)
- Zenichiro Kato
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Yanagido 1-1, 501-1193 Gifu, Japan.
| | | | | |
Collapse
|
22
|
Abstract
This paper examines the developmental substrate for congenital ptosis with particular emphasis on the transcription factors that are thought to be involved. We summarize my research findings and present a review of the relevant literature.
Collapse
Affiliation(s)
- Tristan F W McMullan
- Adnexal Unit, Department of Ophthalmology, Norfolk and Norwich University Hospital, Colney Lane, Norwich, NR4 7UY, UK.
| | | | | |
Collapse
|
23
|
Rowe FJ, Noonan CP. Familial Occurrence of Brown's Syndrome and Duane's Retraction Syndrome. Neuroophthalmology 2006. [DOI: 10.1080/01658100600981071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
|
24
|
Abstract
Strabismus (misalignment of the eyes; also known as "squint") comprises a common heterogeneous group of disorders characterised by a constant or intermittent ocular deviation often associated with amblyopia (uniocular failure of normal visual development) and reduced or absent binocular vision. The associated poor cosmetic appearance may also interfere with social and psychological development. Extensive twin and family studies suggest a significant genetic component to the aetiology of strabismus. The complexity of the molecular basis of strabismus is now beginning to be elucidated with the identification of genetic loci and disease causing genes. Currently greater insights have been gained into the incomitant subtype (differing magnitude of ocular misalignment according to direction of gaze), whereas less is known about the pathogenesis of the more common childhood concomitant strabismus. It is hoped that a greater understanding of the molecular genetics of these disorders will lead to improved knowledge of disease mechanisms and ultimately to more effective treatment. The aim of this paper is to review current knowledge of the molecular genetics of both incomitant and concomitant strabismus.
Collapse
Affiliation(s)
- M Michaelides
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
| | | |
Collapse
|
25
|
Hanisch F, Bau V, Zierz S. Die kongenitale Fibrose der äußeren Augenmuskeln (CFEOM) und andere Phänotypen der kongenitalen kranialen Dysinnervationssyndrome (CCDD). DER NERVENARZT 2005; 76:395-402. [PMID: 15221064 DOI: 10.1007/s00115-004-1742-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Currently, different syndromes with congenital, nonprogressive, sporadic, or familial developmental abnormalities of the cranial nerves and its nuclei are classified as congenital cranial dysinnervation syndromes (CCDD). One of these syndromes, congenital fibrosis of extraocular muscles (CFEOM), is characterized mainly by bilateral ophthalmoplegia of the oculomotor and trochlear nerves. Within the scope of an overview, the case of a 60-year-old patient with congenital fibrosis of extraocular muscles type 1 (CFEOM1) with autosomal dominant inheritance and typical phenotype, but additional progression of the ocular symptoms, is presented. Symptoms were caused by the common C2860-->T mutation in exon 21 of the KIF21A gene on chromosome 12. Further CCDD syndromes include the following phenotypes: congenital ptosis, Duane syndrome, horizontal gaze palsy, Möbius' syndrome, and congenital facial palsy. There are 13 different known gene loci for one of these phenotypes. Five gene products have been identified: the kinesin motor protein Kif21a, the transcription factors ARIX and SALL4, and the carboxypeptidase CPAH.
Collapse
Affiliation(s)
- Frank Hanisch
- Klinik und Poliklinik für Neurologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale.
| | | | | |
Collapse
|
26
|
McCann E, Fryer AE, Newman W, Appleton RE, Kohlhase J. A family with Duane anomaly and distal limb abnormalities: A further family with the arthrogryposis-ophthalmoplegia syndrome. Am J Med Genet A 2005; 139A:123-6. [PMID: 16278891 DOI: 10.1002/ajmg.a.30962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A two-generation family is reported in which three members have Duane anomaly and distal limb abnormalities. All three affected have photopic electroretinogram responses that are abnormal or at the lower limit of the normal range with normal scotopic responses. Two affected family members also have hearing loss. The likeliest diagnosis is the syndrome listed as "arthrogryposis-ophthalmoplegia syndrome" on the London Dysmorphology Database or as "arthrogryposis with oculomotor limitation and electroretinal abnormalities" or "oculomelic aplasia" in OMIM [MIM 108145]. In view of the similarities with Okihiro syndrome, a search for mutations within the SALL4 gene was undertaken, but none were identified.
Collapse
Affiliation(s)
- Emma McCann
- Department of Clinical Genetics, Royal Liverpool Children's Hospital, Liverpool, United Kingdom
| | | | | | | | | |
Collapse
|
27
|
Wabbels BK, Lorenz B, Kohlhase J. No evidence of SALL4-mutations in isolated sporadic duane retraction ?syndrome? (DURS). ACTA ACUST UNITED AC 2004; 131:216-8. [PMID: 15386473 DOI: 10.1002/ajmg.a.30321] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
28
|
Verloes A, Misson JP, Gillet P, Baumann C, Spiritus M, Deprez M. Duane anomaly, congenital myopathy and severe scoliosis in sibs: new AR syndrome? ACTA ACUST UNITED AC 2003; 46:449-52. [PMID: 14659780 DOI: 10.1016/s0003-3995(03)00018-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We report on two sisters who show a similar pattern of anomalies consisting of bilateral Stilling-Türk-Duane retraction syndrome (type 3), non-progressive hypotonia with delayed motor milestones but normal intelligence, severe, early onset scoliosis, and short stature. Muscular biopsy revealed numerous regenerating fibers, but no specific abnormalities among the non-regenerating fibers. This combination of anomalies has not been previously reported, and could represent a new autosomal recessive syndrome. The only differential diagnosis is Crisfield-Dretakis-Sharpe syndrome, a combination of lateral gaze palsy, ptosis, and scoliosis without hypotonia, recessively inherited.
Collapse
Affiliation(s)
- Alain Verloes
- Clinical Genetic Unit, Genetic Federation, Hôpital Robert Debré, 75019 Paris, France.
| | | | | | | | | | | |
Collapse
|
29
|
Engle EC. Applications of molecular genetics to the understanding of congenital ocular motility disorders. Ann N Y Acad Sci 2002; 956:55-63. [PMID: 11960793 DOI: 10.1111/j.1749-6632.2002.tb02808.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The congenital fibrosis syndromes (CFS), including congenital fibrosis of the extraocular muscles (CFEOM) and Duane syndrome (DS), are rare congenital strabismus syndromes that present with nonprogressive restrictive ophthalmoplegia with or without ptosis. Although historically believed to result from primary extraocular muscle (EOM) fibrosis, our laboratory's work is based on the hypothesis that these disorders result from distinct, but analogous, developmental defects of the oculomotor (nIII), trochlear (nIV), and abducens (nVI) nuclei. We have defined three inherited CFEOM phenotypes (CFEOM1-3) and have mapped each phenotype to a distinct genetic locus (FEOM1-3). Individuals with CFEOM1 are born with bilateral ptosis and both eyes fixed in a downward position with absent upgaze and aberrant horizontal gaze. This disorder maps to the FEOM1 locus on chromosome 12cen.(1,2) Neuropathology studies of CFEOM1 reveal the absence of the superior division of oculomotor nerve and its corresponding alpha motor neurons in the midbrain, with abnormalities of target EOMs.(3) These neuropathology findings parallel those previously identified in Duane syndrome, in which there is an absence of nVI and the abducens nerve.(4,5) Individuals with CFEOM2 are born with bilateral ptosis and exotropia. This atypical form of CFEOM maps to the FEOM2 locus on chromosome 11q13 and results from mutations in ARIX (PHOX2A).(6,7) ARIX encodes a homeodomain transcription factor protein previously shown to be required for nIII/nIV development in mouse and zebrafish.(8,9) Together, these findings support the hypothesis that the congenital fibrosis syndromes result from parallel defects in nIII, nIV, and nVI nuclear development. Functional studies of the CFEOM genes should provide additional insight into the unique features of the extraocular lower motor neuron axis in health and disease. (For full (refs. 1-9), see reference list of the main paper.)
Collapse
Affiliation(s)
- Elizabeth C Engle
- Neurology and Pediatrics (Genetics) Children's Hospital, Boston, Massachusetts, USA.
| |
Collapse
|