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Abu-Amero KK, Kondkar AA, Salih MAM, Alorainy IA, Khan AO, Oystreck DT, Bosley TM. Partial chromosome 7 duplication with a phenotype mimicking the HOXA1 spectrum disorder. Ophthalmic Genet 2012; 34:90-6. [DOI: 10.3109/13816810.2012.718850] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Abstract
Congenital heart disease is a major cause of morbidity and mortality throughout life. Mutations in numerous transcription factors have been identified in patients and families with some of the most common forms of cardiac malformations and arrhythmias. This review discusses transcription factor pathways known to be important for normal heart development and how abnormalities in these pathways have been linked to morphological and functional forms of congenital heart defects. A comprehensive, current list of known transcription factor mutations associated with congenital heart disease is provided, but the review focuses primarily on three key transcription factors, Nkx2-5, GATA4, and Tbx5, and their known biochemical and genetic partners. By understanding the interaction partners, transcriptional targets, and upstream activators of these core cardiac transcription factors, additional information about normal heart formation and further insight into genes and pathways affected in congenital heart disease should result.
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Affiliation(s)
- David J McCulley
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
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Abstract
BACKGROUND In 2002, the new term congenital cranial dysinnervation disorder (CCDD) was proposed as a substitute for the traditional concept of congenital fibrosis of the extraocular muscles (CFEOM) based on mounting genetic, neuropathologic, and imaging evidence, suggesting that many, if not all, of these disorders result from a primary neurologic maldevelopment rather than from a muscle abnormality. This report provides an update 8 years after that original report. EVIDENCE ACQUISITION Review of pertinent articles published from January 2003 until June 2010 describing CCDD variants identified under PubMed MeSH terms congenital fibrosis of the extraocular muscles, congenital cranial dysinnervation disorders, individual phenotypes included under the term CCDD, and congenital ocular motility disorders. RESULTS At present, a total of 7 disease genes and 10 phenotypes fall under the CCDD umbrella. A number of additional loci and phenotypes still await gene elucidation, with the anticipation that more syndromes and genes will be identified in the future. Identification of genes and their function, along with advances in neuroimaging, have expanded our understanding of the mechanisms underlying several anomalous eye movement patterns. CONCLUSIONS Current evidence still supports the concept that the CCDDs are primarily due to neurogenic disturbances of brainstem or cranial nerve development. Several CCDDs are now known to have nonophthalmologic associations involving neurologic, neuroanatomic, cerebrovascular, cardiovascular, and skeletal abnormalities.
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When straight eyes won't move: phenotypic overlap of genetically distinct ocular motility disturbances. Can J Ophthalmol 2011; 46:477-80. [PMID: 22153632 DOI: 10.1016/j.jcjo.2011.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/23/2011] [Accepted: 07/28/2011] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To describe the phenotypic similarity in a series of patients with genetically distinct ocular motility disturbances involving straight eyes and different ocular motor pathology. DESIGN Retrospective case series. PARTICIPANTS Clinical and genetic evaluation of 5 patients with straight eyes in the primary position and abnormalities of ocular motility. RESULTS Patients with oculopharyngeal muscular dystrophy, congenital myasthenic syndrome, congenital fibrosis of the extraocular muscles type 3, Bosley-Salih-Alorainy syndrome, and horizontal gaze palsy and progressive scoliosis all had straight eyes in primary position and restricted ocular motility. History, ocular motility patterns, systemic features of individual syndromes, and genetic screening were important diagnostically. CONCLUSIONS A number of congenital and genetic ocular motility syndromes may result in substantial phenotypic overlap, particularly when eyes are straight in primary position and nonophthalmologic features are not apparent or not observed. The range of disorders that may fall into this category is discussed.
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Ferreira RM, Amaral LLF, Gonçalves MVM, Lin K. Imaging findings in congenital cranial dysinnervation disorders. Top Magn Reson Imaging 2011; 22:283-294. [PMID: 24132067 DOI: 10.1097/rmr.0000000000000009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In 2002, the term congenital cranial dysinnervation disorders (CCDDs) was proposed to group heterogeneous syndromes with congenital abnormalities of ocular muscle and facial innervations. The concept of neurogenic etiology has been supported by discovery of genes that are essential to the normal development of brainstem, cranial nerves, and their axonal connections. The CCDDs include Duane retraction syndrome, congenital fibrosis of the extraocular muscles, Möbius syndrome, horizontal gaze palsy with progressive scoliosis, the human homeobox-related disorders, pontine cap tegmental dysplasia, and an expanding list. The purpose of this review was to update the imaging features, as well as clinical and genetic information, regarding cases of CCDDs.
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Affiliation(s)
- Rafael Martins Ferreira
- From the *Clínica Imagem, Florianópolis; †Clinica Medimagem, São Paulo; ‡Joinvile; and §Hospital Universitário-Universidade Federal de Santa Catarina, Florianópolis, Brazil
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Okamoto N, Tamura D, Nishimura G, Shimojima K, Yamamoto T. Submicroscopic deletion of 12q13 including HOXC gene cluster with skeletal anomalies and global developmental delay. Am J Med Genet A 2011; 155A:2997-3001. [PMID: 22069146 DOI: 10.1002/ajmg.a.34324] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 09/04/2011] [Indexed: 11/11/2022]
Abstract
We report on a patient with a submicroscopic deletion of 12q13 detected by array-CGH and confirmed by FISH. He was haploinsufficient for the HOXC gene cluster and some other neighboring genes. HOX genes have an important role in the initial formation of the body. The patient showed characteristic features including severe kyphoscoliosis, digital abnormalities, cardiac anomaly, expressive language, and global developmental delay. Radiologic features of the fingers had some similarities with those for multiple synostosis syndrome. No human genetic disorders due to HOXC abnormalities are yet known. We tentatively assume that his skeletal anomalies are associated with haploinsufficiency of the HOXC gene cluster. Further studies are necessary to determine the clinical importance of haploinsufficiency of the HOXC gene cluster.
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Affiliation(s)
- Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan.
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Makki N, Capecchi MR. Cardiovascular defects in a mouse model of HOXA1 syndrome. Hum Mol Genet 2011; 21:26-31. [PMID: 21940751 DOI: 10.1093/hmg/ddr434] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Congenital heart disease is one of the most common human birth defects, yet many genes and pathways regulating heart development remain unknown. A recent study in humans revealed that mutations in a single Hox gene, HOXA1 (Athabascan Brainstem Dysgenesis Syndrome, Bosley-Salih-Alorainy Syndrome), can cause severe cardiovascular malformations, some of which are lethal without surgical intervention. Since the discovery of the human syndromes, there have been no reports of any Hox mouse mutants with cardiac defects, hampering studies to explore the developmental causes of the human disease. In this study, we identify severe cardiovascular malformations in a Hox mouse model, which mimic the congenital heart defects in HOXA1 syndrome patients. Hoxa1 null mice show defects such as interrupted aortic arch, aberrant subclavian artery and Tetralogy of Fallot, demonstrating that Hoxa1 is required for patterning of the great arteries and outflow tract of the heart. We show that during early embryogenesis, Hoxa1 is expressed in precursors of cardiac neural crest cells (NCCs), which populate the heart. We further demonstrate that Hoxa1 acts upstream of several genes, important for neural crest specification. Thus, our data allow us to suggest a model in which Hoxa1 regulates heart development through its influence on cardiac NCCs, providing insight into the mechanisms underlying the human disease.
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Affiliation(s)
- Nadja Makki
- Howard Hughes Medical Institute and Department of Human Genetics, University of Utah, Salt Lake City, UT 84112-5331, USA
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58
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Samuels ME. Saturation of the human phenome. Curr Genomics 2011; 11:482-99. [PMID: 21532833 PMCID: PMC3048311 DOI: 10.2174/138920210793175886] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 06/22/2010] [Accepted: 06/22/2010] [Indexed: 12/26/2022] Open
Abstract
The phenome is the complete set of phenotypes resulting from genetic variation in populations of an organism. Saturation of a phenome implies the identification and phenotypic description of mutations in all genes in an organism, potentially constrained to those encoding proteins. The human genome is believed to contain 20-25,000 protein coding genes, but only a small fraction of these have documented mutant phenotypes, thus the human phenome is far from complete. In model organisms, genetic saturation entails the identification of multiple mutant alleles of a gene or locus, allowing a consistent description of mutational phenotypes for that gene. Saturation of several model organisms has been attempted, usually by targeting annotated coding genes with insertional transposons (Drosophila melanogaster, Mus musculus) or by sequence directed deletion (Saccharomyces cerevisiae) or using libraries of antisense oligonucleotide probes injected directly into animals (Caenorhabditis elegans, Danio rerio). This paper reviews the general state of the human phenome, and discusses theoretical and practical considerations toward a saturation analysis in humans. Throughout, emphasis is placed on high penetrance genetic variation, of the kind typically asociated with monogenic versus complex traits.
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Affiliation(s)
- Mark E Samuels
- Centre de Recherche de Ste-Justine, 3175, Côte Ste-Catherine, Montréal QC H3T 1C5, Canada
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59
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Abu-Amero KK, Faletra F, Gasparini P, Parentin F, Pensiero S, Alorainy IA, Hellani AM, Catalano D, Bosley TM. Horizontal gaze palsy and progressive scoliosis without ROBO3 mutations. Ophthalmic Genet 2011; 32:212-6. [PMID: 21510772 DOI: 10.3109/13816810.2011.574186] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND To describe clinical and genetic observations in a patient with horizontal gaze palsy and progressive scoliosis (HGPPS) without identified mutations in the ROBO3 gene. MATERIALS AND METHODS Neurologic and orthopedic evaluation of the proband; sequencing all exons, exon-intron boundaries, and promoter region of ROBO3 in the proband and his mother. Array CGH was also carried out in the proband and his mother to evaluate possible chromosomal deletion(s) and/or duplication(s). RESULTS The proband had complete horizontal gaze restriction with full vertical gaze and small amplitude horizontal pendular nystagmus. He also had severe scoliosis and brainstem hypoplasia pathognomonic of HGPPS. However, complete sequencing of ROBO3 twice in both forward and reverse directions did not reveal any mutations. Array CGH investigation revealed no chromosomal abnormalities. CONCLUSIONS This patient had clinical and neuroimaging characteristics considered pathognomonic of HGPPS and yet did not have ROBO3 mutations. A clinical misdiagnosis is unlikely in the absence of facial weakness (typical of Moebius syndrome), deafness (typical of the HOXA1 spectrum), or mental retardation (typical of other central decussation abnormalities). It is perhaps more likely that a phenotype identical to HGPPS can be caused by abnormalities in ROBO3 splice variant expression, by mutations of a gene other than ROBO3, or by some environmental or epigenetic factor(s) inhibiting the action of ROBO3 or its protein product in the developing brainstem.
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Affiliation(s)
- Khaled K Abu-Amero
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
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60
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Hox genes define distinct progenitor sub-domains within the second heart field. Dev Biol 2011; 353:266-74. [PMID: 21385575 DOI: 10.1016/j.ydbio.2011.02.029] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 02/22/2011] [Accepted: 02/28/2011] [Indexed: 12/21/2022]
Abstract
Much of the heart, including the atria, right ventricle and outflow tract (OFT) is derived from a progenitor cell population termed the second heart field (SHF) that contributes progressively to the embryonic heart during cardiac looping. Several studies have revealed anterior-posterior patterning of the SHF, since the anterior region (anterior heart field) contributes to right ventricular and OFT myocardium whereas the posterior region gives rise to the atria. We have previously shown that Retinoic Acid (RA) signal participates to this patterning. We now show that Hoxb1, Hoxa1, and Hoxa3, as downstream RA targets, are expressed in distinct sub-domains within the SHF. Our genetic lineage tracing analysis revealed that Hoxb1, Hoxa1 and Hoxa3-expressing cardiac progenitor cells contribute to both atria and the inferior wall of the OFT, which subsequently gives rise to myocardium at the base of pulmonary trunk. By contrast to Hoxb1(Cre), the contribution of Hoxa1-enhIII-Cre and Hoxa3(Cre)-labeled cells is restricted to the distal regions of the OFT suggesting that proximo-distal patterning of the OFT is related to SHF sub-domains characterized by combinatorial Hox genes expression. Manipulation of RA signaling pathways showed that RA is required for the correct deployment of Hox-expressing SHF cells. This report provides new insights into the regulatory gene network in SHF cells contributing to the atria and sub-pulmonary myocardium.
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Higley MJ, Walkiewicz TW, Miller JH, Curran JG, Towbin RB. Bilateral complete labyrinthine aplasia with bilateral internal carotid artery aplasia, developmental delay, and gaze abnormalities: a presumptive case of a rare HOXA1 mutation syndrome. AJNR Am J Neuroradiol 2011; 32:E23-5. [PMID: 20075099 DOI: 10.3174/ajnr.a1969] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The human HOXA1 mutation syndromes commonly present with abnormalities of the inner ear and ICAs. Previous cases describe varying degrees of hypoplasia or aplasia of the affected structures, often with asymmetric involvement. We present imaging findings documenting complete absence of the ICAs bilaterally with bilateral CLA, which, to our knowledge, has not been previously reported.
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Affiliation(s)
- M J Higley
- Department of Radiology, Phoenix Children's Hospital, Arizona 85016, USA
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62
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Volk AE, Fricke J, Strobl J, Kolling G, Kubisch C, Neugebauer A. Analysis of the CHN1 gene in patients with various types of congenital ocular motility disorders. Graefes Arch Clin Exp Ophthalmol 2010; 248:1351-7. [DOI: 10.1007/s00417-010-1417-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/06/2010] [Accepted: 05/06/2010] [Indexed: 10/19/2022] Open
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63
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Lomberk GA, Imoto I, Gebelein B, Urrutia R, Cook TA. Conservation of the TGFbeta/Labial homeobox signaling loop in endoderm-derived cells between Drosophila and mammals. Pancreatology 2010; 10:74-84. [PMID: 20339309 PMCID: PMC2865486 DOI: 10.1159/000276895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 01/12/2010] [Indexed: 12/11/2022]
Abstract
BACKGROUND/AIMS Midgut formation in Drosophila melanogaster is dependent upon the integrity of a signaling loop in the endoderm which requires the TGFbeta-related peptide, Decapentaplegic, and the Hox transcription factor, Labial. Interestingly, although Labial-like homeobox genes are present in mammals, their participation in endoderm morphogenesis is not clearly understood. METHODS We report the cloning, expression, localization, TGFbeta inducibility, and biochemical properties of the mammalian Labial-like homeobox, HoxA1, in exocrine pancreatic cells that are embryologically derived from the gut endoderm. RESULTS HoxA1 is expressed in pancreatic cell populations as two alternatively spliced messages, encoding proteins that share their N-terminal domain, but either lack or include the homeobox at the C-terminus. Transcriptional regulatory assays demonstrate that the shared N-terminal domain behaves as a strong transcriptional activator in exocrine pancreatic cells. HoxA1 is an early response gene for TGFbeta(1) in pancreatic epithelial cell populations and HoxA1 protein co-localizes with TGFbeta(1) receptors in the embryonic pancreatic epithelium at a time when exocrine pancreatic morphogenesis occurs (days E16 and E17). CONCLUSIONS These results report a role for HoxA1 in linking TGFbeta-mediated signaling to gene expression in pancreatic epithelial cell populations, thus suggesting a high degree of conservation for a TGFbeta/labial signaling loop in endoderm-derived cells between Drosophila and mammals. and IAP.
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Affiliation(s)
- Gwen A. Lomberk
- Laboratory of Epigenetics and Chromatin Dynamics, Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine and Mayo Clinic Cancer Center, Mayo Clinic, Rochester, Minn., USA
| | - Issei Imoto
- Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan,Department of Genome Medicine, Hard Tissue Genome Research Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Brian Gebelein
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Raul Urrutia
- Laboratory of Epigenetics and Chromatin Dynamics, Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine and Mayo Clinic Cancer Center, Mayo Clinic, Rochester, Minn., USA
| | - Tiffany A. Cook
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA,Department of Ophthalmology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA,*Tiffany A. Cook, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, MLC 7003, Cincinnati, OH 45229 (USA), Tel. +1 513 636 6991, Fax +1 513 803 0740, E-Mail
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64
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Makki N, Capecchi MR. Hoxa1 lineage tracing indicates a direct role for Hoxa1 in the development of the inner ear, the heart, and the third rhombomere. Dev Biol 2010; 341:499-509. [PMID: 20171203 DOI: 10.1016/j.ydbio.2010.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/22/2010] [Accepted: 02/10/2010] [Indexed: 11/16/2022]
Abstract
Loss of Hoxa1 function results in severe defects of the brainstem, inner ear, and cranial ganglia in humans and mice as well as cardiovascular abnormalities in humans. Because Hoxa1 is expressed very transiently during an early embryonic stage, it has been difficult to determine whether Hoxa1 plays a direct role in the precursors of the affected organs or if all defects result from indirect effects due to mispatterning of the hindbrain. In this study we use a Hoxa1-IRES-Cre mouse to genetically label the early Hoxa1-expressing cells and determine their contribution to each of the affected organs, allowing us to conclude in which precursor tissue Hoxa1 is expressed. We found Hoxa1 lineage-labeled cells in all tissues expected to be derived from the Hoxa1 domain, such as the facial and abducens nuclei and nerves as well as r4 neural crest cells. In addition, we detected the lineage in derivatives that were not thought to have expressed Hoxa1 during development. In the brainstem, the anterior border of the lineage was found to be in r3, which is more anterior than previously reported. We also observed an interesting pattern of the lineage in the inner ear, namely a strong contribution to the otic epithelium with the exception of sensory patches. Moreover, lineage-labeled cells were detected in the atria and outflow tract of the developing heart. In conclusion, Hoxa1 lineage tracing uncovered new domains of Hoxa1 expression in rhombomere 3, the otic epithelium, and cardiac precursors, suggesting a more direct role for Hoxa1 in development of these tissues than previously believed.
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Affiliation(s)
- Nadja Makki
- Department of Human Genetics, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA
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65
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Rankin JK, Andrews C, Chan WM, Engle EC. HOXA1 mutations are not a common cause of Möbius syndrome. J AAPOS 2010; 14:78-80. [PMID: 20227628 PMCID: PMC2862693 DOI: 10.1016/j.jaapos.2009.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 11/06/2009] [Accepted: 11/10/2009] [Indexed: 11/29/2022]
Abstract
The HOXA1-related syndromes result from autosomal-recessive truncating mutations in the homeobox transcription factor, HOXA1. Limited horizontal gaze and sensorineural deafness are the most common features; affected individuals can also have facial weakness, mental retardation, autism, motor disabilities, central hypoventilation, carotid artery, and/or conotruncal heart defects. Möbius syndrome is also phenotypically heterogeneous, with minimal diagnostic criteria of nonprogressive facial weakness and impaired ocular abduction; mental retardation, autism, motor disabilities, additional eye movements restrictions, hearing loss, hypoventilation, and craniofacial, lingual, and limb abnormalities also occur. We asked, given the phenotypic overlap between these syndromes and the variable expressivity of both disorders, whether individuals with Möbius syndrome might harbor mutations in HOXA1. Our results suggest that HOXA1 mutations are not a common cause of sporadic Möbius syndrome in the general population.
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Affiliation(s)
- Jessica K Rankin
- Department of Neurology, Children's Hospital Boston, Boston, Massachusetts, USA
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66
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Erickson RP. Autosomal recessive diseases among the Athabaskans of the southwestern United States: recent advances and implications for the future. Am J Med Genet A 2010; 149A:2602-11. [PMID: 19842189 DOI: 10.1002/ajmg.a.33052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Genetic and linguistic data suggest that the Na-Dene, of which the Athabaskans are the largest group, are part of a later immigration into the Americas than the first Amerind immigration. Whether a second and third immigration can be separated seems unlikely but continued cross-Bering Strait exchanges may have masked what was a greater separation in the past. The movement of tribes into Siberia appears to have involved a genetic bottleneck leading to at least one disease allele shared by Eskimo/Aleuts and Navajos and a second possibly shared by the Navajo and a Siberian population, but not the same Siberian population that share deep linguistic affinities with the Navajo. A second bottleneck appears to have occurred with the migration of Athabaskans from Northwest North America to the Southwestern United States along the Rocky Mountains. This bottleneck is reflected in several rare recessive diseases shared by the Navajo and Apache. Finally, the Navajo were captured and imprisoned under conditions which led to severe population loss. This, and the "hiding away" of a small number of Navajos in what is now the Western portion of the reservation, led to a Navajo-specific bottleneck(s) resulting in an increased frequency of several rare recessive diseases among the Navajo. Prejudice against human genetic research is high among the Southwestern Athabaskans but attempts to bridge the gap are now occurring. The involvement of Navajo scientists in this process is especially encouraging.
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Affiliation(s)
- Robert P Erickson
- Department of Pediatrics, University of Arizona, Tucson, Arizona 85701, USA.
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Congenital Cranial Dysinnervation Disorders: Facts and Perspectives to Understand Ocular Motility Disorders. ESSENTIALS IN OPHTHALMOLOGY 2010. [DOI: 10.1007/978-3-540-85851-5_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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68
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Barkovich AJ, Millen KJ, Dobyns WB. A developmental and genetic classification for midbrain-hindbrain malformations. Brain 2009; 132:3199-230. [PMID: 19933510 PMCID: PMC2792369 DOI: 10.1093/brain/awp247] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 08/04/2009] [Accepted: 08/21/2009] [Indexed: 01/30/2023] Open
Abstract
Advances in neuroimaging, developmental biology and molecular genetics have increased the understanding of developmental disorders affecting the midbrain and hindbrain, both as isolated anomalies and as part of larger malformation syndromes. However, the understanding of these malformations and their relationships with other malformations, within the central nervous system and in the rest of the body, remains limited. A new classification system is proposed, based wherever possible, upon embryology and genetics. Proposed categories include: (i) malformations secondary to early anteroposterior and dorsoventral patterning defects, or to misspecification of mid-hindbrain germinal zones; (ii) malformations associated with later generalized developmental disorders that significantly affect the brainstem and cerebellum (and have a pathogenesis that is at least partly understood); (iii) localized brain malformations that significantly affect the brain stem and cerebellum (pathogenesis partly or largely understood, includes local proliferation, cell specification, migration and axonal guidance); and (iv) combined hypoplasia and atrophy of putative prenatal onset degenerative disorders. Pertinent embryology is discussed and the classification is justified. This classification will prove useful for both physicians who diagnose and treat patients with these disorders and for clinical scientists who wish to understand better the perturbations of developmental processes that produce them. Importantly, both the classification and its framework remain flexible enough to be easily modified when new embryologic processes are described or new malformations discovered.
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Affiliation(s)
- A James Barkovich
- Neuroradiology Room L371, University of California at San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143-0628, USA.
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69
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Oystreck DT, Khan AO, Vila-Coro AA, Oworu O, Al-Tassan N, Chan WM, Engle EC, Bosley TM. Synergistic divergence: a distinct ocular motility dysinnervation pattern. Invest Ophthalmol Vis Sci 2009; 50:5213-6. [PMID: 19578026 PMCID: PMC2787189 DOI: 10.1167/iovs.08-2928] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To summarize the clinical, neuroradiologic, and genetic observations in a group of patients with unilateral synergistic divergence (SD). METHODS Five unrelated patients with unilateral SD underwent ophthalmic and orthoptic examinations; three of them also had magnetic resonance imaging of the brain and orbits. Three patients underwent genetic evaluation of genes known to affect ocular motility: KIF21A, PHOX2A, HOXA1, and ROBO3. RESULTS The patients did not meet the clinical criteria for CFEOM types 1, 2, or 3. Each patient had severe adduction weakness on the affected side and large-angle exotropia in primary gaze that increased on attempted contralateral gaze because of anomalous abduction. Magnetic resonance imaging revealed a much smaller medial rectus muscle in the involved SD orbit. Oculomotor cranial nerves were present in the one patient imaged appropriately. Genetic sequencing in three patients revealed no mutations in KIF21A, PHOX2A, HOXA1, or ROBO3. CONCLUSIONS SD should be classified as a distinct congenital ocular motility pattern within congenital cranial dysinnervation disorders. It may be caused by denervation of the medial rectus with dysinnervation of the ipsilateral lateral rectus by the oculomotor nerve precipitated by genetic abnormalities (some currently identified) or by local environmental, teratogenic, or epigenetic disturbances.
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Affiliation(s)
- Darren T Oystreck
- Pediatric Ophthalmology Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
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70
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Williams D. Cardiac biology and disease in invertebrates. Vet Clin North Am Exot Anim Pract 2009; 12:1-9, v. [PMID: 19131027 DOI: 10.1016/j.cvex.2008.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It may seem ridiculous to consider cardiac diseases in sub-vertebrate animals; when on earth is a tarantula, a butterfly or a snail going to be presented as a clinical case with heart failure or a congenital cardiac abnormality? This article examines the work of research groups investigating invertebrates as valuable models of heart disease in man. Examining invertebrates with gene defects similar to those in human patients with heart disease, congenital or acquired, allows us to probe deeply into the aetiopathogenesis of many cardiac conditions.
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Affiliation(s)
- David Williams
- Department of Veterinary Medicine, University of Cambridge, St John's College, Cambridge CB3 0ES, UK.
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