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Roshandel D, Semnani F, Rayati Damavandi A, Masoudi A, Baradaran-Rafii A, Watson SL, Morgan WH, McLenachan S. Genetic predisposition to ocular surface disorders and opportunities for gene-based therapies. Ocul Surf 2023; 29:150-165. [PMID: 37192706 DOI: 10.1016/j.jtos.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/24/2023] [Accepted: 05/09/2023] [Indexed: 05/18/2023]
Abstract
The ocular surface, comprised of the corneal and conjunctival epithelium, innervation system, immune components, and tear-film apparatus, plays a key role in ocular integrity as well as comfort and vision. Gene defects may result in congenital ocular or systemic disorders with prominent ocular surface involvement. Examples include epithelial corneal dystrophies, aniridia, ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome, xeroderma pigmentosum (XP), and hereditary sensory and autonomic neuropathy. In addition, genetic factors may interact with environmental risk factors in the development of several multifactorial ocular surface disorders (OSDs) such as autoimmune disorders, allergies, neoplasms, and dry eye disease. Advanced gene-based technologies have already been introduced in disease modelling and proof-of-concept gene therapies for monogenic OSDs. For instance, patient-derived induced pluripotent stem cells have been used for modelling aniridia-associated keratopathy (AAK), XP, and EEC syndrome. Moreover, CRISPR/Cas9 genome editing has been used for disease modelling and/or gene therapy for AAK and Meesmann's epithelial corneal dystrophy. A better understanding of the role of genetic factors in OSDs may be helpful in designing personalized disease models and treatment approaches. Gene-based approaches in monogenic OSDs and genetic predisposition to multifactorial OSDs such as immune-mediated disorders and neoplasms with known or possible genetic risk factors has been seldom reviewed. In this narrative review, we discuss the role of genetic factors in monogenic and multifactorial OSDs and potential opportunities for gene therapy.
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Affiliation(s)
- Danial Roshandel
- Lions Eye Institute, Perth, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA, Australia
| | - Farbod Semnani
- School of Public Health, Tehran University of Medical Sciences (TUMS), Tehran, Iran; School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Amirmasoud Rayati Damavandi
- School of Public Health, Tehran University of Medical Sciences (TUMS), Tehran, Iran; School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Ali Masoudi
- Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Alireza Baradaran-Rafii
- Department of Ophthalmology, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Stephanie L Watson
- The University of Sydney, Save Sight Institute, Discipline of Ophthalmology, Sydney Medical School, Sydney, New South Wales, Australia
| | - William H Morgan
- Lions Eye Institute, Perth, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA, Australia
| | - Samuel McLenachan
- Lions Eye Institute, Perth, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA, Australia.
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González-Duarte A, Cotrina-Vidal M, Kaufmann H, Norcliffe-Kaufmann L. Familial dysautonomia. Clin Auton Res 2023; 33:269-280. [PMID: 37204536 DOI: 10.1007/s10286-023-00941-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/30/2023] [Indexed: 05/20/2023]
Abstract
Familial dysautonomia (FD) is an autosomal recessive hereditary sensory and autonomic neuropathy (HSAN, type 3) expressed at birth with profound sensory loss and early death. The FD founder mutation in the ELP1 gene arose within the Ashkenazi Jews in the sixteenth century and is present in 1:30 Jews of European ancestry. The mutation yield a tissue-specific skipping of exon 20 and a loss of function of the elongator-1 protein (ELP1), which is essential for the development and survival of neurons. Patients with FD produce variable amounts of ELP1 in different tissues, with the brain producing mostly mutant transcripts. Patients have excessive blood pressure variability due to the failure of the IXth and Xth cranial nerves to carry baroreceptor signals. Neurogenic dysphagia causes frequent aspiration leading to chronic pulmonary disease. Characteristic hyperadrenergic "autonomic crises" consisting of brisk episodes of severe hypertension, tachycardia, skin blotching, retching, and vomiting occur in all patients. Progressive features of the disease include retinal nerve fiber loss and blindness, and proprioceptive ataxia with severe gait impairment. Chemoreflex failure may explain the high frequency of sudden death in sleep. Although 99.5% of patients are homozygous for the founder mutation, phenotypic severity varies, suggesting that modifier genes impact expression. Medical management is currently symptomatic and preventive. Disease-modifying therapies are close to clinical testing. Endpoints to measure efficacy have been developed, and the ELP1 levels are a good surrogate endpoint for target engagement. Early intervention may be critical for treatment to be successful.
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Affiliation(s)
- Alejandra González-Duarte
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA.
- Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, CdMx, México.
| | - Maria Cotrina-Vidal
- Department of Neurology, Stroke Division. New York University School of Medicine, New York, NY, USA
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, NY, USA
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3
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Saito-Diaz K, Dietrich P, Wu HF, Sun X, Patel AJ, Wzientek CG, Prudden AR, Boons GJ, Chen S, Studer L, Xu B, Dragatsis I, Zeltner N. Genipin Crosslinks the Extracellular Matrix to Rescue Developmental and Degenerative Defects, and Accelerates Regeneration of Peripheral Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.22.533831. [PMID: 36993570 PMCID: PMC10055431 DOI: 10.1101/2023.03.22.533831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The peripheral nervous system (PNS) is essential for proper body function. A high percentage of the population suffer nerve degeneration or peripheral damage. For example, over 40% of patients with diabetes or undergoing chemotherapy develop peripheral neuropathies. Despite this, there are major gaps in the knowledge of human PNS development and therefore, there are no available treatments. Familial Dysautonomia (FD) is a devastating disorder that specifically affects the PNS making it an ideal model to study PNS dysfunction. FD is caused by a homozygous point mutation in ELP1 leading to developmental and degenerative defects in the sensory and autonomic lineages. We previously employed human pluripotent stem cells (hPSCs) to show that peripheral sensory neurons (SNs) are not generated efficiently and degenerate over time in FD. Here, we conducted a chemical screen to identify compounds able to rescue this SN differentiation inefficiency. We identified that genipin, a compound prescribed in Traditional Chinese Medicine for neurodegenerative disorders, restores neural crest and SN development in FD, both in the hPSC model and in a FD mouse model. Additionally, genipin prevented FD neuronal degeneration, suggesting that it could be offered to patients suffering from PNS neurodegenerative disorders. We found that genipin crosslinks the extracellular matrix, increases the stiffness of the ECM, reorganizes the actin cytoskeleton, and promotes transcription of YAP-dependent genes. Finally, we show that genipin enhances axon regeneration in an in vitro axotomy model in healthy sensory and sympathetic neurons (part of the PNS) and in prefrontal cortical neurons (part of the central nervous system, CNS). Our results suggest genipin can be used as a promising drug candidate for treatment of neurodevelopmental and neurodegenerative diseases, and as a enhancer of neuronal regeneration.
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Affiliation(s)
- Kenyi Saito-Diaz
- Center for Molecular Medicine, University of Georgia, Athens GA, USA
| | - Paula Dietrich
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Hsueh-Fu Wu
- Center for Molecular Medicine, University of Georgia, Athens GA, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
| | - Xin Sun
- College of Engineering, University of Georgia, Athens GA, USA
| | | | | | | | - Geert-Jan Boons
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Department of Chemistry, University of Georgia, Athens, GA, USA
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Shuibing Chen
- Department of Surgery and Department of Biochemistry at Weill Cornell Medical College, New York, NY, USA
- Center for Stem Cell Biology, Sloan Kettering Institute, New York, NY, USA
| | - Lorenz Studer
- Center for Stem Cell Biology, Sloan Kettering Institute, New York, NY, USA
- Department of Developmental Biology, Sloan Kettering Institute, New York, NY, USA
| | - Bingqian Xu
- College of Engineering, University of Georgia, Athens GA, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, TN, USA
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens GA, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens GA, USA
- Department of Cellular Biology, University of Georgia, Athens GA, USA
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4
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Cheney AM, Costello SM, Pinkham NV, Waldum A, Broadaway SC, Cotrina-Vidal M, Mergy M, Tripet B, Kominsky DJ, Grifka-Walk HM, Kaufmann H, Norcliffe-Kaufmann L, Peach JT, Bothner B, Lefcort F, Copié V, Walk ST. Gut microbiome dysbiosis drives metabolic dysfunction in Familial dysautonomia. Nat Commun 2023; 14:218. [PMID: 36639365 PMCID: PMC9839693 DOI: 10.1038/s41467-023-35787-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 12/18/2022] [Indexed: 01/15/2023] Open
Abstract
Familial dysautonomia (FD) is a rare genetic neurologic disorder caused by impaired neuronal development and progressive degeneration of both the peripheral and central nervous systems. FD is monogenic, with >99.4% of patients sharing an identical point mutation in the elongator acetyltransferase complex subunit 1 (ELP1) gene, providing a relatively simple genetic background in which to identify modifiable factors that influence pathology. Gastrointestinal symptoms and metabolic deficits are common among FD patients, which supports the hypothesis that the gut microbiome and metabolome are altered and dysfunctional compared to healthy individuals. Here we show significant differences in gut microbiome composition (16 S rRNA gene sequencing of stool samples) and NMR-based stool and serum metabolomes between a cohort of FD patients (~14% of patients worldwide) and their cohabitating, healthy relatives. We show that key observations in human subjects are recapitulated in a neuron-specific Elp1-deficient mouse model, and that cohousing mutant and littermate control mice ameliorates gut microbiome dysbiosis, improves deficits in gut transit, and reduces disease severity. Our results provide evidence that neurologic deficits in FD alter the structure and function of the gut microbiome, which shifts overall host metabolism to perpetuate further neurodegeneration.
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Affiliation(s)
- Alexandra M Cheney
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Stephanann M Costello
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Nicholas V Pinkham
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Annie Waldum
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Susan C Broadaway
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Maria Cotrina-Vidal
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Marc Mergy
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Brian Tripet
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Douglas J Kominsky
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Heather M Grifka-Walk
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | | | - Jesse T Peach
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
| | - Valérie Copié
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
| | - Seth T Walk
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
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Vahidi G, Flook H, Sherk V, Mergy M, Lefcort F, Heveran CM. Bone biomechanical properties and tissue-scale bone quality in a genetic mouse model of familial dysautonomia. Osteoporos Int 2021; 32:2335-2346. [PMID: 34036438 PMCID: PMC8563419 DOI: 10.1007/s00198-021-06006-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/11/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Familial dysautonomia (FD) is associated with a high prevalence of bone fractures, but the impacts of the disease on bone mass and quality are unclear. The purpose of this study was to evaluate tissue through whole-bone scale bone quality in a mouse model of FD. METHODS Femurs from mature adult Tuba1a-Cre; Elp1LoxP/LoxP conditional knockouts (CKO) (F = 7, M = 4) and controls (F = 5, M = 6) were evaluated for whole-bone flexural material properties, trabecular microarchitecture and cortical geometry, and areal bone mineral density (BMD). Adjacent maps spanning the thickness of femur midshaft cortical bone assessed tissue-scale modulus (nanoindentation), bone mineralization, mineral maturity, and collagen secondary structure (Raman spectroscopy). RESULTS Consistent with prior studies on this mouse model, the Elp1 CKO mouse model recapitulated several key hallmarks of human FD, with one difference being the male mice tended to have a more severe phenotype than females. Deletion of Elp1 in neurons (using the neuronal-specific Tuba1a-cre) led to a significantly reduced whole-bone toughness but not strength or modulus. Elp1 CKO female mice had reduced trabecular microarchitecture (BV/TV, Tb.Th, Conn.D.) but not cortical geometry. The mutant mice also had a small but significant reduction in cortical bone nanoindentation modulus. While bone tissue mineralization and mineral maturity were not impaired, FD mice may have altered collagen secondary structure. Changes in collagen secondary structure were inversely correlated with bone toughness. BMD from dual-energy x-ray absorptiometry (DXA) was unchanged with FD. CONCLUSION The deletion of Elp1 in neurons is sufficient to generate a mouse line which demonstrates loss of whole-bone toughness, consistent with the poor bone quality suspected in the clinical setting. The Elp1 CKO model, as with human FD, impacts the nervous system, gut, kidney function, mobility, gait, and posture. The bone quality phenotype of Elp1 CKO mice, which includes altered microarchitecture and tissue-scale material properties, is complex and likely influenced by these multisystemic changes. This mouse model may provide a useful platform to not only investigate the mechanisms responsible for bone fragility in FD, but also a powerful model system with which to evaluate potential therapeutic interventions for bone fragility in FD patients.
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Affiliation(s)
- G Vahidi
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA
| | - H Flook
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA
| | - V Sherk
- Department of Orthopaedics, University of Colorado School of Medicine, Aurora, CO, USA
| | - M Mergy
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT, USA
| | - F Lefcort
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT, USA
| | - C M Heveran
- Department of Mechanical & Industrial Engineerings, Montana State University, Bozeman, MT, USA.
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6
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Jacot-Descombes S, Keshav N, Brosch CMS, Wicinski B, Warda T, Norcliffe-Kaufmann L, Kaufmann H, Varghese M, Hof PR. Von Economo Neuron Pathology in Familial Dysautonomia: Quantitative Assessment and Possible Implications. J Neuropathol Exp Neurol 2021; 79:1072-1083. [PMID: 32954436 DOI: 10.1093/jnen/nlaa095] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Von Economo neurons (VENs) and fork cells are principally located in the anterior cingulate cortex (ACC) and the frontoinsular cortex (FI). Both of these regions integrate inputs from the autonomic nervous system (ANS) and are involved in decision-making and perception of the emotional states of self and others. Familial dysautonomia (FD) is an orphan disorder characterized by autonomic dysfunction and behavioral abnormalities including repetitive behavior and emotional rigidity, which are also seen in autism spectrum disorder. To understand a possible link between the ANS and the cortical regions implicated in emotion regulation we studied VENs and fork cells in an autonomic disorder. We determined the densities of VENs, fork cells, and pyramidal neurons and the ratio of VENs and fork cells to pyramidal neurons in ACC and FI in 4 FD patient and 6 matched control brains using a stereologic approach. We identified alterations in densities of VENs and pyramidal neurons and their distributions in the ACC and FI in FD brains. These data suggest that alterations in migration and numbers of VENs may be involved in FD pathophysiology thereby supporting the notion of a functional link between VENs, the ANS and the peripheral nervous system in general.
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Affiliation(s)
- Sarah Jacot-Descombes
- Nash Family Department of Neuroscience.,Friedman Brain Institute.,Icahn School of Medicine at Mount Sinai, New York, New York; University Center of Legal Medicine, Lausanne - Geneva, Geneva University Hospitals
| | - Neha Keshav
- Nash Family Department of Neuroscience.,Friedman Brain Institute.,Seaver Autism Center for Research and Treatment
| | - Carla Micaela Santos Brosch
- Nash Family Department of Neuroscience.,Department of Mental Health and Psychiatry, University Hospitals and School of Medicine Geneva, Switzerland
| | - Bridget Wicinski
- Nash Family Department of Neuroscience.,Friedman Brain Institute
| | - Tahia Warda
- Nash Family Department of Neuroscience.,Friedman Brain Institute
| | - Lucy Norcliffe-Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, New York
| | - Horacio Kaufmann
- Department of Neurology, Dysautonomia Center, New York University School of Medicine, New York, New York
| | - Merina Varghese
- Nash Family Department of Neuroscience.,Friedman Brain Institute
| | - Patrick R Hof
- Nash Family Department of Neuroscience.,Friedman Brain Institute.,Seaver Autism Center for Research and Treatment
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Abstract
PURPOSE OF REVIEW Genetic polyneuropathies are rare and clinically heterogeneous. This article provides an overview of the clinical features, neurologic and electrodiagnostic findings, and management strategies for Charcot-Marie-Tooth disease and other genetic polyneuropathies as well as an algorithm for genetic testing. RECENT FINDINGS In the past 10 years, many of the mutations causing genetic polyneuropathies have been identified. International collaborations have led to the development of consortiums that are undertaking careful genotype-phenotype correlations to facilitate the development of targeted therapies and validation of outcome measures for future clinical trials. Clinical trials are currently under way for some genetic polyneuropathies. SUMMARY Readers are provided a framework to recognize common presentations of various genetic polyneuropathies and a rationale for current diagnostic testing and management strategies in genetic polyneuropathies.
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8
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Ramírez-Estudillo A, González-Saldivar G, Espinosa-Soto I, González-Cortez J, Salcido-Montenegro A. Riley-Day Syndrome in a Hispanic Infant of Non-Jewish Ashkenazi Descent. J Clin Diagn Res 2017; 11:ND01-ND02. [PMID: 28892950 DOI: 10.7860/jcdr/2017/25584.10152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/31/2017] [Indexed: 11/24/2022]
Abstract
Riley-Day syndrome is an autosomal recessive sensory and autonomic neuropathy. Patients present a lack of fungiform papilla, alacrima and usually feeding difficulties. It is present almost exclusively in Ashkenazi Jewish individuals and has a poor prognosis. We describe an unusual case of Riley-Day syndrome with pseudostrabismus in a non-Ashkenazi Jewish patient. A one-year-old female infant was referred for evaluation of strabismus, absence of fungiform papillae, feeding difficulty, gastroesophageal reflux and episodes of self-mutilation. Deep tendon reflexes were depressed, the blinking rate and corneal reflex were diminished as well and corneas were opaque due to corneal erosions. Reduced lacrimal production was confirmed by the Schirmer test. Eye drops were recommended every 2-3 hours for corneal erosion and the patient was referred to the genetics department for further diagnostic confirmation.
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Affiliation(s)
- Abel Ramírez-Estudillo
- Consultant, Ophtalmology Unit, Fundación Hospital Nuestra Señora de la Luz, IAP, Ciudad de México, Mexico
| | - Gerardo González-Saldivar
- Consultant, Ophtalmology Unit, Fundación Hospital Nuestra Señora de la Luz, IAP, Ciudad de México, Mexico
| | - Itzel Espinosa-Soto
- Consultant, Ophtalmology Unit, Fundación Hospital Nuestra Señora de la Luz, IAP, Ciudad de México, Mexico
| | - Jesús González-Cortez
- Consultant, Ophtalmology Unit, Fundación Hospital Nuestra Señora de la Luz, IAP, Ciudad de México, Mexico
| | - Alejandro Salcido-Montenegro
- Consultant, Endocrine Service, Hospital Universitario "Dr. José E. González", Universidad Autónoma de Nuevo, Monterrey, Nuevo León, Mexico
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9
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Ohlen SB, Russell ML, Brownstein MJ, Lefcort F. BGP-15 prevents the death of neurons in a mouse model of familial dysautonomia. Proc Natl Acad Sci U S A 2017; 114:5035-5040. [PMID: 28439028 PMCID: PMC5441694 DOI: 10.1073/pnas.1620212114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Hereditary sensory and autonomic neuropathy type III, or familial dysautonomia [FD; Online Mendelian Inheritance in Man (OMIM) 223900], affects the development and long-term viability of neurons in the peripheral nervous system (PNS) and retina. FD is caused by a point mutation in the gene IKBKAP/ELP1 that results in a tissue-specific reduction of the IKAP/ELP1 protein, a subunit of the Elongator complex. Hallmarks of the disease include vasomotor and cardiovascular instability and diminished pain and temperature sensation caused by reductions in sensory and autonomic neurons. It has been suggested but not demonstrated that mitochondrial function may be abnormal in FD. We previously generated an Ikbkap/Elp1 conditional-knockout mouse model that recapitulates the selective death of sensory (dorsal root ganglia) and autonomic neurons observed in FD. We now show that in these mice neuronal mitochondria have abnormal membrane potentials, produce elevated levels of reactive oxygen species, are fragmented, and do not aggregate normally at axonal branch points. The small hydroxylamine compound BGP-15 improved mitochondrial function, protecting neurons from dying in vitro and in vivo, and promoted cardiac innervation in vivo. Given that impairment of mitochondrial function is a common pathological component of neurodegenerative diseases such as amyotrophic lateral sclerosis and Alzheimer's, Parkinson's, and Huntington's diseases, our findings identify a therapeutic approach that may have efficacy in multiple degenerative conditions.
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Affiliation(s)
- Sarah B Ohlen
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717
| | - Magdalena L Russell
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717
| | | | - Frances Lefcort
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT 59717;
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Dietrich P, Dragatsis I. Familial Dysautonomia: Mechanisms and Models. Genet Mol Biol 2016; 39:497-514. [PMID: 27561110 PMCID: PMC5127153 DOI: 10.1590/1678-4685-gmb-2015-0335] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/16/2016] [Indexed: 11/22/2022] Open
Abstract
Hereditary Sensory and Autonomic Neuropathies (HSANs) compose a heterogeneous group of genetic disorders characterized by sensory and autonomic dysfunctions. Familial Dysautonomia (FD), also known as HSAN III, is an autosomal recessive disorder that affects 1/3,600 live births in the Ashkenazi Jewish population. The major features of the disease are already present at birth and are attributed to abnormal development and progressive degeneration of the sensory and autonomic nervous systems. Despite clinical interventions, the disease is inevitably fatal. FD is caused by a point mutation in intron 20 of the IKBKAP gene that results in severe reduction in expression of IKAP, its encoded protein. In vitro and in vivo studies have shown that IKAP is involved in multiple intracellular processes, and suggest that failed target innervation and/or impaired neurotrophic retrograde transport are the primary causes of neuronal cell death in FD. However, FD is far more complex, and appears to affect several other organs and systems in addition to the peripheral nervous system. With the recent generation of mouse models that recapitulate the molecular and pathological features of the disease, it is now possible to further investigate the mechanisms underlying different aspects of the disorder, and to test novel therapeutic strategies.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
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11
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Norcliffe-Kaufmann L, Slaugenhaupt SA, Kaufmann H. Familial dysautonomia: History, genotype, phenotype and translational research. Prog Neurobiol 2016; 152:131-148. [PMID: 27317387 DOI: 10.1016/j.pneurobio.2016.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 01/30/2023]
Abstract
Familial dysautonomia (FD) is a rare neurological disorder caused by a splice mutation in the IKBKAP gene. The mutation arose in the 1500s within the small Jewish founder population in Eastern Europe and became prevalent during the period of rapid population expansion within the Pale of Settlement. The carrier rate is 1:32 in Jews descending from this region. The mutation results in a tissue-specific deficiency in IKAP, a protein involved in the development and survival of neurons. Patients homozygous for the mutations are born with multiple lesions affecting mostly sensory (afferent) fibers, which leads to widespread organ dysfunction and increased mortality. Neurodegenerative features of the disease include progressive optic atrophy and worsening gait ataxia. Here we review the progress made in the last decade to better understand the genotype and phenotype. We also discuss the challenges of conducting controlled clinical trials in this rare medically fragile population. Meanwhile, the search for better treatments as well as a neuroprotective agent is ongoing.
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Affiliation(s)
| | - Susan A Slaugenhaupt
- Center for Human Genetic Research, Massachusetts General Hospital Research Institute and Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA.
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12
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Lefler S, Cohen MA, Kantor G, Cheishvili D, Even A, Birger A, Turetsky T, Gil Y, Even-Ram S, Aizenman E, Bashir N, Maayan C, Razin A, Reubinoff BE, Weil M. Familial Dysautonomia (FD) Human Embryonic Stem Cell Derived PNS Neurons Reveal that Synaptic Vesicular and Neuronal Transport Genes Are Directly or Indirectly Affected by IKBKAP Downregulation. PLoS One 2015; 10:e0138807. [PMID: 26437462 PMCID: PMC4593545 DOI: 10.1371/journal.pone.0138807] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 09/03/2015] [Indexed: 12/21/2022] Open
Abstract
A splicing mutation in the IKBKAP gene causes Familial Dysautonomia (FD), affecting the IKAP protein expression levels and proper development and function of the peripheral nervous system (PNS). Here we found new molecular insights for the IKAP role and the impact of the FD mutation in the human PNS lineage by using a novel and unique human embryonic stem cell (hESC) line homozygous to the FD mutation originated by pre implantation genetic diagnosis (PGD) analysis. We found that IKBKAP downregulation during PNS differentiation affects normal migration in FD-hESC derived neural crest cells (NCC) while at later stages the PNS neurons show reduced intracellular colocalization between vesicular proteins and IKAP. Comparative wide transcriptome analysis of FD and WT hESC-derived neurons together with the analysis of human brains from FD and WT 12 weeks old embryos and experimental validation of the results confirmed that synaptic vesicular and neuronal transport genes are directly or indirectly affected by IKBKAP downregulation in FD neurons. Moreover we show that kinetin (a drug that corrects IKBKAP alternative splicing) promotes the recovery of IKAP expression and these IKAP functional associated genes identified in the study. Altogether, these results support the view that IKAP might be a vesicular like protein that might be involved in neuronal transport in hESC derived PNS neurons. This function seems to be mostly affected in FD-hESC derived PNS neurons probably reflecting some PNS neuronal dysfunction observed in FD.
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Affiliation(s)
- Sharon Lefler
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Malkiel A Cohen
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Gal Kantor
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - David Cheishvili
- Department of Developmental Biology and Cancer Research, Institute of Medical Research Israel-Canada, Hebrew University Medical School, Jerusalem, Israel
| | - Aviel Even
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Anastasya Birger
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Tikva Turetsky
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Yaniv Gil
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Sharona Even-Ram
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Einat Aizenman
- Department of Obstetrics and Gynecology, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Nibal Bashir
- Department of Obstetric and Gynecology, Hadassah Hospital Mount Scopus, Hebrew University Medical School, Jerusalem, Israel
| | - Channa Maayan
- Department of Pediatrics, Hadassah Hospital Mount Scopus, Hebrew University Medical School, Jerusalem, Israel
| | - Aharon Razin
- Department of Developmental Biology and Cancer Research, Institute of Medical Research Israel-Canada, Hebrew University Medical School, Jerusalem, Israel
| | - Benjamim E Reubinoff
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel; Department of Obstetrics and Gynecology, Hadassah Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Miguel Weil
- Laboratory for Neurodegenerative Diseases and Personalized Medicine, Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, The Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
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Palma JA, Norcliffe-Kaufmann L, Fuente-Mora C, Percival L, Mendoza-Santiesteban C, Kaufmann H. Current treatments in familial dysautonomia. Expert Opin Pharmacother 2014; 15:2653-71. [PMID: 25323828 PMCID: PMC4236240 DOI: 10.1517/14656566.2014.970530] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy (type III). The disease is caused by a point mutation in the IKBKAP gene that affects the splicing of the elongator-1 protein (ELP-1) (also known as IKAP). Patients have dramatic blood pressure instability due to baroreflex failure, chronic kidney disease, and impaired swallowing leading to recurrent aspiration pneumonia, which results in chronic lung disease. Diminished pain and temperature perception result in neuropathic joints and thermal injuries. Impaired proprioception leads to gait ataxia. Optic neuropathy and corneal opacities lead to progressive visual loss. AREAS COVERED This article reviews current therapeutic strategies for the symptomatic treatment of FD, as well as the potential of new gene-modifying agents. EXPERT OPINION Therapeutic focus on FD is centered on reducing the catecholamine surges caused by baroreflex failure. Managing neurogenic dysphagia with effective protection of the airway passages and prompt treatment of aspiration pneumonias is necessary to prevent respiratory failure. Sedative medications should be used cautiously due to the risk of respiratory depression. Non-invasive ventilation during sleep effectively manages apneas and prevents hypercapnia. Clinical trials of compounds that increase levels of IKAP (ELP-1) are underway and will determine whether they can reverse or slow disease progression.
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Affiliation(s)
- Jose-Alberto Palma
- New York University School of Medicine, Dysautonomia Center, Department of Neurology , 530 First Avenue, Suite 9Q New York, NY 10016 , USA +1 212 263 7225 ;
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14
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Abstract
Familial dysautonomia (FD) is a rare hereditary disorder caused by mutations within the gene that encodes for I-κ-B kinase complex associated protein (IKAP). A deficiency of IKAP affects the development of primary sensory neurons including those carrying baroreflex afferent volleys, a feature that explains their characteristic sensory loss and labile blood pressure. This review describes the history, the genotype of FD and the unusual cardiovascular autonomic phenotype of these patients. We outline the main consequences of a failure to receive information from arterial baroreceptors, including the characteristic "autonomic storms" and severe end-organ target damage.
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Norcliffe-Kaufmann L, Axelrod F, Kaufmann H. Afferent baroreflex failure in familial dysautonomia. Neurology 2011; 75:1904-11. [PMID: 21098405 DOI: 10.1212/wnl.0b013e3181feb283] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Familial dysautonomia (FD) is due to a genetic deficiency of the protein IKAP, which affects development of peripheral neurons. Patients with FD display complex abnormalities of the baroreflex of unknown cause. METHODS To test the hypothesis that the autonomic phenotype of FD is due to selective impairment of afferent baroreceptor input, we examined the autonomic and neuroendocrine responses triggered by stimuli that either engage (postural changes) or bypass (cognitive/emotional) afferent baroreflex pathways in 50 patients with FD and compared them to those of normal subjects and to those of patients with pure autonomic failure (PAF), a disorder with selective impairment of efferent autonomic neurons. RESULTS During upright tilt, in patients with FD and in patients with PAF blood pressure fell markedly but the heart rate increased in PAF and decreased in FD. Plasma norepinephrine levels failed to increase in both groups. Vasopressin levels increased appropriately in patients with PAF but failed to increase in patients with FD. Head-down tilt increased blood pressure in both groups but increased heart rate only in patients with FD. Mental stress evoked a marked increase in blood pressure and heart rate in patients with FD but little change in those with PAF. CONCLUSION The failure to modulate sympathetic activity and to release vasopressin by baroreflex-mediated stimuli together with marked sympathetic activation during cognitive tasks indicate selective failure of baroreceptor afference. These findings indicate that IKAP is critical for the development of afferent baroreflex pathways and has therapeutic implications in the management of these patients.
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Abstract
Ashkenazi Jewish genetic screening has expanded significantly in the past 4 decades. Individuals of Eastern European (Ashkenazi) Jewish (AJ) descent are at increased risk of having offspring with particular genetic diseases that have significant morbidity and mortality. In addition, there are some disorders, such as cystic fibrosis, for which northern European Caucasians are at comparable risk with those of an AJ background. Carrier screening for many of these Jewish genetic disorders has become standard of care. As technology advances, so does the number of disorders for which screening is available. Thus, we need to continue to be cognizant of informed consent, test sensitivity, confidentiality, prenatal diagnosis, preimplantation genetic screening, and public health concerns regarding testing.
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Loss of mouse Ikbkap, a subunit of elongator, leads to transcriptional deficits and embryonic lethality that can be rescued by human IKBKAP. Mol Cell Biol 2008; 29:736-44. [PMID: 19015235 DOI: 10.1128/mcb.01313-08] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Familial dysautonomia (FD), a devastating hereditary sensory and autonomic neuropathy, results from an intronic mutation in the IKBKAP gene that disrupts normal mRNA splicing and leads to tissue-specific reduction of IKBKAP protein (IKAP) in the nervous system. To better understand the roles of IKAP in vivo, an Ikbkap knockout mouse model was created. Results from our study show that ablating Ikbkap leads to embryonic lethality, with no homozygous Ikbkap knockout (Ikbkap(-)(/)(-)) embryos surviving beyond 12.5 days postcoitum. Morphological analyses of the Ikbkap(-)(/)(-) conceptus at different stages revealed abnormalities in both the visceral yolk sac and the embryo, including stunted extraembryonic blood vessel formation, delayed entry into midgastrulation, disoriented dorsal primitive neural alignment, and failure to establish the embryonic vascular system. Further, we demonstrate downregulation of several genes that are important for neurulation and vascular development in the Ikbkap(-)(/)(-) embryos and show that this correlates with a defect in transcriptional elongation-coupled histone acetylation. Finally, we show that the embryonic lethality resulting from Ikbkap ablation can be rescued by a human IKBKAP transgene. For the first time, we demonstrate that IKAP is crucial for both vascular and neural development during embryogenesis and that protein function is conserved between mouse and human.
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Abstract
The aim of carrier testing is to identify carrier couples at risk of having offspring with a serious genetic (autosomal recessive) disorder. Carrier couples are offered genetic consultation where their reproductive options, including prenatal diagnosis, are explained. The Ashkenazi Jewish population is at increased risk for several recessively inherited disorders (Tay-Sachs disease, Cystic fibrosis, Canavan disease, Gaucher disease, Familial Dysautonomia, Niemann-Pick disease, Fanconi anemia, and Bloom syndrome). Unlike Tay-Sachs disease, there is no simple biochemical or enzymatic test to detect carriers for these other disorders. However, with the rapid identification of disease-causing genes in recent years, DNA-based assays are increasingly available for carrier detection. Approximately 5% of the world's population carries a mutation affecting the globin chains of the hemoglobin molecule. Among the most common of these disorders are the thalassemias. The global birth rate of affected infants is at least 2 per 1000 (in unscreened populations), with the greatest incidence in Southeast Asian, Indian, Mediterranean, and Middle Eastern ethnic groups. Carriers are detected by evaluation of red cell indices and morphology, followed by more sophisticated hematological testing and molecular analyses. The following issues need to be considered in the development of a carrier screening program: (1) test selection based on disease severity and test accuracy; (2) funding for testing and genetic counselling; (3) definition of the target population to be screened; (4) development of a public and professional education program; (5) informed consent for screening; and (6) awareness of community needs.
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Affiliation(s)
- Hilary Vallance
- Biochemical Genetics Laboratory, Department of Pathology and Laboratory Medicine, Children's and Women's Health Centre of British Columbia, Vancouver, Canada.
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19
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Technical standards and guidelines for reproductive screening in the Ashkenazi Jewish population. Genet Med 2008; 10:57-72. [PMID: 18197058 DOI: 10.1097/gim.0b013e31815f6eac] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
DISCLAIMER These Technical Standards and Guidelines were developed primarily as an educational resource for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to these standards and guidelines is voluntary and does not necessarily assure a successful medical outcome. These Standards and Guidelines should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the clinical laboratory geneticist should apply his or her own professional judgment to the specific circumstances presented by the individual patient or specimen. Clinical laboratory geneticists are encouraged to document in the patient's record the rationale for the use of a particular procedure or test, whether or not it is in conformance with these Standards and Guidelines. They also are advised to take notice of the date any particular standard or guidelines was adopted, and to consider other relevant medical and scientific information that becomes available after that date.
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Fares F, Badarneh K, Abosaleh M, Harari-Shaham A, Diukman R, David M. Carrier frequency of autosomal-recessive disorders in the Ashkenazi Jewish population: should the rationale for mutation choice for screening be reevaluated? Prenat Diagn 2008; 28:236-41. [DOI: 10.1002/pd.1943] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Rubin BY, Anderson SL. The molecular basis of familial dysautonomia: overview, new discoveries and implications for directed therapies. Neuromolecular Med 2007; 10:148-56. [PMID: 17985250 DOI: 10.1007/s12017-007-8019-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 10/17/2007] [Indexed: 01/05/2023]
Abstract
Familial dysautonomia (FD) is a sensory and autonomic neuropathy that affects the development and survival of sensory, sympathetic, and some parasympathetic neurons. It is autosomally inherited and occurs almost exclusively among individuals of Ashkenazi Jewish descent. The pathological and clinical manifestations of FD have been extensively studied and therapeutic modalities have, until recently, focused primarily on addressing the symptoms experienced by those with this fatal disorder. The primary FD-causing mutation is an intronic nucleotide substitution that alters the splicing of the IKBKAP-derived transcript. Recent efforts have resulted in the development of new therapeutic modalities that facilitate the increased production of the correctly spliced transcript and mitigate the symptoms of those with FD. Furthermore, the recent demonstration of the reduced presence of monoamine oxidase A in cells and tissues of individuals with FD has provided new insight into the cause of hypertensive crises experienced by these patients.
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Affiliation(s)
- Berish Y Rubin
- Department of Biological Sciences, Laboratory for Familial Dysautonomia Research, Fordham University, 441 East Fordham Road, Bronx, NY 10458, USA.
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22
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Abstract
Small-fiber neuropathy is a peripheral nerve disease that most commonly presents in middle-aged and older people, who develop burning pain in their feet. Although it can be caused by disorders of metabolism such as diabetes, chronic infections (such as with human immunodeficiency virus), genetic abnormalities, toxicity from various drugs, and autoimmune diseases, the cause often remains a mystery because standard electrophysiologic tests for nerve injury do not detect small-fiber function. Inadequate ability to test for and diagnose small-fiber neuropathies has impeded patient care and research, but new tools offer promise. Infrequently, the underlying cause of small-fiber dysfunction is identified and disease-modifying therapy can be instituted. More commonly, the treatments for small-fiber neuropathy involve symptomatic treatment of neuropathic pain.
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Affiliation(s)
- Ezekiel Fink
- Department of Anesthesiology, Neurology, and Neuropathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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23
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Butler J, Fleming P, Webb D. Congenital insensitivity to pain—review and report of a case with dental implications. ACTA ACUST UNITED AC 2006; 101:58-62. [PMID: 16360608 DOI: 10.1016/j.tripleo.2005.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Revised: 07/26/2005] [Accepted: 08/05/2005] [Indexed: 11/22/2022]
Abstract
Pain is a protective mechanism for the body. Absence of pain is a symptom in several disorders, both congenital and acquired. The congenital types are present at birth and affect the number and distribution of types of nerve fibers. At present, 5 types of hereditary sensory and autonomic neuropathies have been identified. The various disorders within this group are classified according to the different patterns of sensory and autonomic dysfunction and peripheral neuropathy and the presence of additional clinical features such as learning disability. However, the field is currently moving away from classification based on clinical presentation toward classification based on underlying genetic abnormality. In the absence of pain, patients are at risk of late presentation with illnesses or injuries, and have an increased incidence of traumatic injury. Self-mutilation is an almost invariable feature of these disorders. We report the case of a patient with congenital insensitivity to pain that presented with self-mutilation injuries to his hands and oral tissues caused by biting. The severe nature of these injuries necessitated serial extraction of his primary teeth soon after eruption, which led to a cessation of the problem. The mutilation has not returned following the eruption of the first of his permanent teeth, suggesting that he has learned not to bite himself, even though to do so causes him no discomfort.
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Casella EB, Bousso A, Corvello CM, Fruchtengarten LVG, Diament AJ. Episodic somnolence in an infant with Riley-Day syndrome. Pediatr Neurol 2005; 32:273-4. [PMID: 15797185 DOI: 10.1016/j.pediatrneurol.2004.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Accepted: 09/27/2004] [Indexed: 11/20/2022]
Abstract
Familial dysautonomia is an autosomal recessive congenital neuropathy that occurs almost exclusively in the Ashkenazi Jewish population and has rarely been diagnosed in the neonatal period in unaffected families. This report describes a patient who, during the neonatal period, had episodes of marked decrease in the level of consciousness with durations of 4-15 hours. Other signs and symptoms included the absence of fungiform papillae of the tongue, areflexia, and failure to thrive. The diagnosis was confirmed by the demonstration of mutations in the IkappaB kinase complex-associated protein gene with the identification of IVS20 (+6T --> C) which is responsible for more than 99.5% of known Ashkenazi Jewish patients with familial dysautonomia. The prognosis of this disease and the possibility of genetic counseling are clearly related with an early definitive diagnosis, and this patient illustrates the importance of episodes of somnolence as a possible sign of familial dysautonomia.
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Affiliation(s)
- Erasmo B Casella
- Pediatric Neurology Unit, University of São Paulo, São Paulo, Brazil
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25
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Mitra N, Ye TZ, Smith A, Chuai S, Kirchhoff T, Peterlongo P, Nafa K, Phillips MS, Offit K, Ellis NA. Localization of Cancer Susceptibility Genes by Genome-wide Single-Nucleotide Polymorphism Linkage-Disequilibrium Mapping. Cancer Res 2004; 64:8116-25. [PMID: 15520224 DOI: 10.1158/0008-5472.can-04-1411] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
With the large numbers of single nucleotide polymorphisms (SNPs) available and new technologies that permit high throughput genotyping, we have investigated the possibility of the localization of disease genes with genome-wide panels of SNP markers and taking advantage of the linkage-disequilibrium (LD) between the disease gene and closely linked markers. For this purpose, we selected cases from the Ashkenazi Jewish population, in which the mutant alleles are expected to be identical by descent from a common founder and the regions of LD encompassing these mutant alleles are large. As a validation of this approach for localization, we performed two trials: one in autosomal recessive Bloom syndrome, in which a unique mutation of the BLM gene is present at elevated frequencies in cases, and the other in autosomal dominant hereditary nonpolyposis colorectal cancer (HNPCC), in which a unique mutation of MSH2 is present at elevated frequencies. In the Bloom syndrome trial, we genotyped 3,258 SNPs in 10 Jewish Bloom syndrome cases and 31 non-Bloom syndrome Jewish persons as a comparison group. In the HNPCC trial, we genotyped 8,549 SNPS in 13 Jewish HNPCC cases whose colon cancers exhibited microsatellite instability and in 63 healthy Jews as a comparison group. To identify significant associations, we performed (a) Fisher's exact test comparing genotypes at each locus in cases versus controls and (b) a haplotype analysis by estimating the frequency of haplotypes with the expectation-maximization algorithm and comparing haplotype frequencies in cases versus controls by logistic regression and a maximum likelihood ratio method. In the Bloom syndrome trial, by Fisher's exact test, statistically significant association was detected at a single locus, TSC0754862, which is a locus 1.7 million bp from BLM. Two-locus, three-locus, and four-locus haplotypes that included TSC0754862 and flanked BLM were also statistically more frequent in cases versus controls. In the HNPCC trial, although a significant P value was not obtained by the single SNP genotype analysis, significant associations were detected for several multilocus haplotypes in an 11-million-bp region that contained the MSH2 gene. This work demonstrates the power of the LD mapping approach in an isolated population and its general applicability to the identification of novel cancer-causing genes.
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Affiliation(s)
- Nandita Mitra
- Department of Epidemiology and Biostatistics, and Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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26
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Abstract
PURPOSE OF REVIEW The hereditary sensory neuropathies, also known as the hereditary sensory and autonomic neuropathies, are a clinically and genetically heterogeneous group of disorders. As they are not as common as Charcot-Marie-Tooth disease, they do not receive the same level of attention, but there have been major advances in the identification of the causative genes in the past decade. Certain forms of hereditary sensory and autonomic neuropathy, especially hereditary sensory and autonomic neuropathy type I, which has minimal autonomic involvement and is more accurately termed hereditary sensory neuropathy type I, can present in a very similar fashion to certain forms of Charcot-Marie-Tooth disease (Charcot-Marie-Tooth type 2B, see below), and therefore it is important that clinicians who regularly manage patients with neuropathy are familiar with the latest developments in the hereditary sensory and autonomic neuropathies. This review will concentrate on the recent genetic advances in hereditary sensory and autonomic neuropathy, and especially on those forms that overlap clinically with Charcot-Marie-Tooth disease, hence the title of the review 'Hereditary sensory neuropathies' rather than hereditary sensory and autonomic neuropathies.
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27
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Slatkin M. A population-genetic test of founder effects and implications for Ashkenazi Jewish diseases. Am J Hum Genet 2004; 75:282-93. [PMID: 15208782 PMCID: PMC1216062 DOI: 10.1086/423146] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 06/07/2004] [Indexed: 01/13/2023] Open
Abstract
A founder effect can account for the presence of an allele at an unusually high frequency in an isolated population if the allele is selectively neutral and if all copies are identical by descent with a copy that either was carried by a founder individual or arose by mutation later. Here, a statistical test of both aspects of the founder-effect hypothesis is developed. The test is performed by a modified version of a program that implements the Slatkin-Bertorelle test of neutrality. The test is applied to several disease-associated alleles found predominantly in Ashkenazi Jews. Despite considerable uncertainty about the demographic history of Ashkenazi Jews and their ancestors, available genetic data are consistent with a founder effect resulting from a severe bottleneck in population size between a.d. 1100 and a.d. 1400 and an earlier bottleneck in a.d. 75, at the beginning of the Jewish Diaspora. The relatively high frequency of alleles causing four different lysosomal storage disorders, including Tay-Sachs disease and Gaucher disease, can be accounted for if the disease-associated alleles are recessive in their effects on reproductive fitness.
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Affiliation(s)
- Montgomery Slatkin
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA.
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28
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Lehavi O, Aizenstein O, Bercovich D, Pavzner D, Shomrat R, Orr-Urtreger A, Yaron Y. Screening for familial dysautonomia in Israel: evidence for higher carrier rate among Polish Ashkenazi Jews. GENETIC TESTING 2004; 7:139-42. [PMID: 12885336 DOI: 10.1089/109065703322146830] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Familial dysautonomia (FD) is an autosomal recessive disorder characterized by hereditary sensory and autonomic neuropathies. Although extremely rare in most populations, FD is common among Ashkenazi Jews (AJ), with a calculated carrier frequency of 1 in 30, based on disease prevalence. The gene for FD was recently identified as IKBKAP. One major mutation (IVS2 + 6T --> C) is responsible in >99.5% of cases among AJ. The purpose of this study was to determine the actual frequency of FD carriers in the AJ population in Israel and to determine whether carriers are more frequent among a subpopulation of AJ from Poland. The study group included 1267 Jews of Ashkenazi origin who were referred for routine DNA screening tests. These included 1100 individuals who were full AJ and 167 who were part AJ. None had a family history of FD. Mutation analysis for (IVS2 + 6T --> C) was performed by PCR amplification followed by restriction enzyme analysis. All positive cases were confirmed by DHPLC WAVE( trade mark ). Among the 1100 full AJ tested, 34 were found to be FD carriers (1:32). The incidence of mutation carriers was significantly higher in AJ of Polish descent (1:18) compared to AJ of non-Polish descent (1:99). Among the 167 individuals who were part AJ, there were 3 carriers (1:56). The incidence of FD among AJ, particularly those of Polish background, warrants population screening. Population screening may be performed by denaturing high-performance liquid chromatography.
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Affiliation(s)
- Ofer Lehavi
- Prenatal Diagnosis Division, Genetic Institute and Department of Obstetrics and Gynecology, Lis Maternity Hospital, Tel Aviv, Israel
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29
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Austerlitz F, Kalaydjieva L, Heyer E. Detecting Population Growth, Selection and Inherited Fertility From Haplotypic Data in Humans. Genetics 2003; 165:1579-86. [PMID: 14668404 PMCID: PMC1462861 DOI: 10.1093/genetics/165.3.1579] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
The frequency of a rare mutant allele and the level of allelic association between this allele and one or several closely linked markers are frequently measured in genetic epidemiology. Both quantities are related to the time elapsed since the appearance of the mutation in the population and the intrinsic growth rate of the mutation (which may be different from the average population growth rate). Here, we develop a method that uses these two kinds of genetic data to perform a joint estimation of the age of the mutation and the minimum growth rate that is compatible with its present frequency. In absence of demographic data, it provides a useful estimate of population growth rate. When such data are available, contrasts among estimates from several loci allow demographic processes, affecting all loci similarly, to be distinguished from selection, affecting loci differently. Testing these estimates on populations for which data are available for several disorders shows good congruence with demographic data in some cases whereas in others higher growth rates are obtained, which may be the result of selection or hidden demographic processes.
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Affiliation(s)
- Frédéric Austerlitz
- Laboratoire Ecologie, Systématique et Evolution, Université Paris-Sud, F-91405 Orsay, France.
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30
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Rechitsky S, Verlinsky O, Kuliev A, Ozen RS, Masciangelo C, Lifchez A, Verlinsky Y. Preimplantation genetic diagnosis for familial dysautonomia. Reprod Biomed Online 2003; 6:488-93. [PMID: 12831599 DOI: 10.1016/s1472-6483(10)62172-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Familial dysautonomia (FD) is the most common congenital sensory neuropathy in Ashkenazi Jews, caused by a single major mutation in the IKBKAP gene. Effective management for this severe debilitating disease is still not available, making preimplantation genetic diagnosis (PGD) a useful option for at-risk couples to establish an FD free pregnancy from the outset. PGD was performed for a couple with a previous affected child with FD, using first and second polar body testing to preselect mutation-free oocytes, based on mutation analysis with simultaneous testing of two closely linked markers, D9S58 and D9S1677. Of 15 tested oocytes, 11 carried information about both polar bodies' genotype, of which seven were predicted to be free of the FD gene. Three embryos resulting from these oocytes were transferred back to the patient, resulting in a triplet pregnancy and the birth of three unaffected children confirmed to be free of FD. This is the first PGD for FD, providing an alternative for those at-risk couples who cannot accept prenatal diagnosis and termination of pregnancy as an option for avoiding FD.
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Affiliation(s)
- S Rechitsky
- Reproductive Genetics Institute, Chicago, IL 60657, USA
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31
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Josaitis CA, Matisoff M. Familial dysautonomia in review: diagnosis and treatment of ocular manifestations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 506:71-80. [PMID: 12613891 DOI: 10.1007/978-1-4615-0717-8_9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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32
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Fini ME, Slaugenhaupt SA. Enzymatic mechanisms in corneal ulceration with specific reference to familial dysautonomia: potential for genetic approaches. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 506:629-39. [PMID: 12613971 DOI: 10.1007/978-1-4615-0717-8_89] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Affiliation(s)
- M Elizabeth Fini
- Vision Research Laboratories, New England Eye Center, Tufts University School of Medicine and Tufts Center for Vision Research, Boston, Massachusetts, USA
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33
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Dong J, Edelmann L, Bajwa AM, Kornreich R, Desnick RJ. Familial dysautonomia: detection of the IKBKAP IVS20(+6T --> C) and R696P mutations and frequencies among Ashkenazi Jews. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 110:253-7. [PMID: 12116234 DOI: 10.1002/ajmg.10450] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that occurs almost exclusively in the Ashkenazi Jewish (AJ) population. Mutations in the IkappaB kinase complex-associated protein (IKBKAP) gene cause FD. Two IKBKAP mutations, IVS20(+6T --> C) and R696P, have been identified in FD patients of AJ descent. The splice site mutation IVS20(+6T --> C) is responsible for > 99.5% of known AJ patients with FD, and haplotype analyses were consistent with a common founder. In contrast, the R696P mutation has been identified in only a few AJ patients. To facilitate carrier detection, a single PCR and allele-specific oligonucleotide (ASO) hybridization assay was developed to facilitate the detection of both the IVS20(+6T --> C) and R696P mutations. Screening of 2,518 anonymous AJ individuals from the New York metropolitan area revealed a carrier frequency for IVS20(+6T --> C) of 1 in 32 (3.2%; 95% CI, 2.5-3.9%), similar to the previously estimated carrier frequency (3.3%) based on disease incidence. No carrier was identified for the R696P lesion, indicating that the mutation was rare in this population (< 1 in 2,500). This sensitive and specific assay should facilitate carrier screening for FD mutations in the AJ community, as well as postnatal diagnostic testing.
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Affiliation(s)
- Jianli Dong
- Department of Human Genetics, Mount Sinai School of Medicine of New York University, New York, New York 10029, USA
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34
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Abstract
Familial dysautonomia is a developmental disorder of the sensory and autonomic nervous system. Recent studies have shown that two mutations in the gene IKBKAP are responsible for the disease. IKAP, the IKBKAP-encoded protein, is a member of the recently identified human Elongator complex. The major FD mutation is a splice mutation that results in aberrant tissue-specific mRNA splicing.
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Affiliation(s)
- Susan A Slaugenhaupt
- Harvard Institute of Human Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
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35
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Abstract
Familial dysautonomia is a severe autosomal-recessive neurodegenerative disease that primarily affects the Ashkenazi Jewish population. We present the mapping of alpha-catulin and show that it maps precisely to the familial dysautonomia candidate region on 9q31. Patient sequence analysis identified two new sequence variants, which show linkage disequilibrium with this disease. A G to A transition at nucleotide 423 in exon 3 is a silent base change that does not alter the Val residue at position 141. A G to C transversion at nucleotide 1579 changes the Glu at postion 527 to Gln. These base changes were analyzed in several patients, unaffected Ashkenazi Jewish controls, and non-Jewish controls. Because of the presence of these sequence variants in several unaffected individuals, alpha-catulin is unlikely to be the causative gene in this disease.
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Affiliation(s)
- P C Demacio
- Department of Genetics, Hospital for Sick Children, University of Toronto, ON, Canada
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36
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Sakae N, Yamada T, Arakawa K, Taniwaki T, Ohyagi Y, Furuya H, Ohnishi A, Kira J. Adult-onset hereditary sensory and autonomic neuropathy accompanied by anosmia but without skin ulceration. Acta Neurol Scand 2001; 104:316-9. [PMID: 11696028 DOI: 10.1034/j.1600-0404.2001.00051.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We report a novel type of hereditary sensory and autonomic neuropathy (HSAN) with adult onset in a Japanese family. One male and 2 females of 6 siblings were affected. They developed anosmia initially at the ages of 20-50 years, followed by anhidrosis and sensory loss. Skin ulceration was absent. Both superficial and deep sensation were impaired in the most distal parts of all 4 limbs. Orthostatic hypotension was present in all patients. This is a unique subtype of HSAN distinct from the HSAN I-V described by Dyck.
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Affiliation(s)
- N Sakae
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
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37
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Abstract
The Jews are an ancient people with a history spanning several millennia. Genetic studies over the past 50 years have shed light on Jewish origins, the relatedness of Jewish communities and the genetic basis of Mendelian disorders among Jewish peoples. In turn, these observations have been used to develop genetic testing programmes and, more recently, to attempt to discover new genes for susceptibility to common diseases.
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Affiliation(s)
- H Ostrer
- Human Genetics Program, New York University School of Medicine, MSB 136, New York, New York 10016, USA.
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38
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Jaffé A, Bush A. Genetic contributions to rare childhood lung diseases. Paediatr Respir Rev 2001; 2:268-75. [PMID: 12052329 DOI: 10.1053/prrv.2001.0150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Epidemiological studies have suggested that many rare diseases with respiratory involvement have a genetic component. Molecular advances have increased the understanding of the pathophysiology of these diseases which has led to better diagnostic and prognostic methods. There may be many genes responsible for diseases such as primary ciliary dyskinesia and systemic lupus erythematosus in addition to the effect of modifier genes. The genotype:phenotype correlation in these diseases remains to be elucidated. In some diseases, such as familial dysautonomia and sickle cell, the gene has been identified which allows for accurate pre-natal testing. Further, in diseases where the genetic abnormality is known, such as chronic granulomatous disease, gene therapy remains a realistic prospect and phase I studies are about to commence or currently underway. This article reviews those rare diseases in which there is or is likely to be a significant genetic contribution.
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Affiliation(s)
- A Jaffé
- Department of Respiratory Paediatrics, Level 4, Chelsea Wing, Royal Brompton and Harefield NHS Trust, Sydney Street, London, SW3 6NP, England, UK.
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Weese-Mayer DE, Silvestri JM, Huffman AD, Smok-Pearsall SM, Kowal MH, Maher BS, Cooper ME, Marazita ML. Case/control family study of autonomic nervous system dysfunction in idiopathic congenital central hypoventilation syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 100:237-45. [PMID: 11343310 DOI: 10.1002/ajmg.1249] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Children with idiopathic congenital central hypoventilation syndrome (CCHS) have a complex phenotype consistent with an imbalance of the autonomic nervous system (ANS). Since CCHS may be genetic in origin, we hypothesized that relatives of individuals with CCHS may exhibit symptoms of ANS dysfunction (ANSD), albeit in a milder form. We tested this hypothesis by assessing aspects of ANS function in relatives of CCHS cases vs. relatives of matched controls with a scripted questionnaire. Only those 35 symptoms of ANSD exhibited by > or =5% of the CCHS cases were included in the analysis as the basis for determining ANSD affection status. Two different arbitrary ANSD affection status definitions are presented in detail: any case, control, or relative with positive findings (1) in two or more symptoms, or (2) in two or more systems. The subjects included in the analysis totaled 2,353, including 56 CCHS cases, 56 age-, gender-, and race-matched controls, and their families. Under each of the two arbitrary ANSD affection statuses, CCHS cases and parents of cases were more likely to be affected than controls and parents of controls (P < 0.001 for both comparisons), 16% of the CCHS siblings had the ANSD phenotype with two or more symptoms, compared to 4% of control siblings (P = 0.03). Aunts and uncles of the CCHS cases were also significantly more likely to have two or more ANSD symptoms than were aunts and uncles of the controls (P= 0.009). These results support our hypothesis and also indicate that relatives of the CCHS cases tended to manifest a milder spectrum of ANSD, with fewer systems and/or fewer symptoms than the cases.
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Affiliation(s)
- D E Weese-Mayer
- Department of Pediatrics, Rush Children's Hospital at Rush-Presbyterian-St. Luke's Medical Center, Rush University, Chicago, Illinois 60612, USA.
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40
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Marazita ML, Maher BS, Cooper ME, Silvestri JM, Huffman AD, Smok-Pearsall SM, Kowal MH, Weese-Mayer DE. Genetic segregation analysis of autonomic nervous system dysfunction in families of probands with idiopathic congenital central hypoventilation syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 100:229-36. [PMID: 11343309 DOI: 10.1002/ajmg.1284] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Idiopathic congenital central hypoventilation syndrome (CCHS) is a very rare syndrome with major respiratory complications. Hypothesizing that CCHS is the most severe manifestation of general autonomic nervous system dysfunction (ANSD), we applied a case-control family study design to investigate the genetics of ANSD. Fifty-two probands with CCHS were identified, as well as 52 age-, race-, and gender-matched controls. ANSD phenotypic features were characterized in the cases, controls, and their family members. Our earlier studies found that most ANSD symptoms were more likely in CCHS cases and their relatives than in controls and their relatives (P < 0.05). The goal of the current study was to determine if the familiality of ANSD was consistent with a genetic pattern. We performed major locus segregation analysis of ANSD utilizing regressive models. CCHS probands were assumed to be affected; controls and relatives were designated as affected if they had two or more relevant symptoms. The hypothesis of "no transmission and no familial effects" was rejected in both case and control families. Case families were consistent with transmission of a major effect; control families were not (the difference in the pattern of results was significant, P < 0.0001). In the total data set, the best-fitting model was codominant Mendelian inheritance of a major gene for ANSD. These case-control family studies support our hypothesis that CCHS is the most severe manifestation of a general ANSD, with a family pattern consistent with Mendelian transmission, and demonstrate the potential utility of the approach to studies of other, similarly intractable disorders.
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Affiliation(s)
- M L Marazita
- Department of Oral and Maxillofacial Surgery and Division of Oral Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
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41
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Anderson SL, Coli R, Daly IW, Kichula EA, Rork MJ, Volpi SA, Ekstein J, Rubin BY. Familial dysautonomia is caused by mutations of the IKAP gene. Am J Hum Genet 2001; 68:753-8. [PMID: 11179021 PMCID: PMC1274486 DOI: 10.1086/318808] [Citation(s) in RCA: 313] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2000] [Accepted: 01/10/2001] [Indexed: 11/03/2022] Open
Abstract
The defective gene DYS, which is responsible for familial dysautonomia (FD) and has been mapped to a 0.5-cM region on chromosome 9q31, has eluded identification. We identified and characterized the RNAs encoded by this region of chromosome 9 in cell lines derived from individuals homozygous for the major FD haplotype, and we observed that the RNA encoding the IkappaB kinase complex-associated protein (IKAP) lacks exon 20 and, as a result of a frameshift, encodes a truncated protein. Sequence analysis reveals a T-->C transition in the donor splice site of intron 20. In individuals bearing a minor FD haplotype, a missense mutation in exon 19 disrupts a consensus serine/threonine kinase phosphorylation site. This mutation results in defective phosphorylation of IKAP. These mutations were observed to be present in a random sample of Ashkenazi Jewish individuals, at approximately the predicted carrier frequency of FD. These findings demonstrate that mutations in the gene encoding IKAP are responsible for FD.
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Affiliation(s)
- Sylvia L. Anderson
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
| | - Rocco Coli
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
| | - Ira W. Daly
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
| | - Elizabeth A. Kichula
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
| | - Matthew J. Rork
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
| | - Sabrina A. Volpi
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
| | - Josef Ekstein
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
| | - Berish Y. Rubin
- Department of Biological Sciences, Fordham University, Bronx, NY; and Dor Yeshorim, The Committee for Prevention of Jewish Diseases, Brooklyn, NY/Jerusalem
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42
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Slaugenhaupt SA, Blumenfeld A, Gill SP, Leyne M, Mull J, Cuajungco MP, Liebert CB, Chadwick B, Idelson M, Reznik L, Robbins CM, Makalowska I, Brownstein MJ, Krappmann D, Scheidereit C, Maayan C, Axelrod FB, Gusella JF. Tissue-specific expression of a splicing mutation in the IKBKAP gene causes familial dysautonomia. Am J Hum Genet 2001; 68:598-605. [PMID: 11179008 PMCID: PMC1274473 DOI: 10.1086/318810] [Citation(s) in RCA: 423] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2000] [Accepted: 01/10/2001] [Indexed: 11/04/2022] Open
Abstract
Familial dysautonomia (FD; also known as "Riley-Day syndrome"), an Ashkenazi Jewish disorder, is the best known and most frequent of a group of congenital sensory neuropathies and is characterized by widespread sensory and variable autonomic dysfunction. Previously, we had mapped the FD gene, DYS, to a 0.5-cM region on chromosome 9q31 and had shown that the ethnic bias is due to a founder effect, with >99.5% of disease alleles sharing a common ancestral haplotype. To investigate the molecular basis of FD, we sequenced the minimal candidate region and cloned and characterized its five genes. One of these, IKBKAP, harbors two mutations that can cause FD. The major haplotype mutation is located in the donor splice site of intron 20. This mutation can result in skipping of exon 20 in the mRNA of patients with FD, although they continue to express varying levels of wild-type message in a tissue-specific manner. RNA isolated from lymphoblasts of patients is primarily wild-type, whereas only the deleted message is seen in RNA isolated from brain. The mutation associated with the minor haplotype in four patients is a missense (R696P) mutation in exon 19, which is predicted to disrupt a potential phosphorylation site. Our findings indicate that almost all cases of FD are caused by an unusual splice defect that displays tissue-specific expression; and they also provide the basis for rapid carrier screening in the Ashkenazi Jewish population.
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Affiliation(s)
- Susan A. Slaugenhaupt
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Anat Blumenfeld
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Sandra P. Gill
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Maire Leyne
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - James Mull
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Math P. Cuajungco
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Christopher B. Liebert
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Brian Chadwick
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Maria Idelson
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Luba Reznik
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Christiane M. Robbins
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Izabela Makalowska
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Michael J. Brownstein
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Daniel Krappmann
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Claus Scheidereit
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Channa Maayan
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - Felicia B. Axelrod
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
| | - James F. Gusella
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown; Harvard Institute of Human Genetics, Harvard Medical School, Boston; Departments of Clinical Biochemistry and Pediatrics, Hadassah University Hospital, Jerusalem; Laboratory of Genetics, National Institute of Mental Health and National Human Genome Research Institute, and Genome Technology Branch, National Human Genome Research Institute, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda; Max-Delbrück-Centrum for Molecular Medicine, Berlin; and Department of Pediatrics, New York University Medical Center, New York
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43
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Abstract
Although hereditary disease has been recognized for centuries, only recently has it become the prevailing explanation for numerous human pathologies. Before the 1970s, physicians saw genetic disease as rare and irrelevant to clinical care. But, by the 1990s, genes seemed to be critical factors in virtually all human disease. Here I explore some perspectives on how and why this happened, by looking at two genetic diseases--familial dysautonomia and phenylketonuria.
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Affiliation(s)
- M S Lindee
- School of Arts and Sciences, Department of History and Sociology of Science, Logan Hall, Suite 303, 249 South 36th Street, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6304, USA.
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44
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Abstract
Hirschsprung disease (HSCR), or congenital intestinal aganglionosis, is a relatively common disorder of neural crest migration. It has a strong genetic basis, although simple Mendelian inheritance is rarely observed. Hirschsprung disease is associated with several other anomalies and syndromes, and animal models for these conditions exist. Mutations in the RET gene are responsible for approximately half of familial cases and a smaller fraction of sporadic cases. Mutations in genes that encode RET ligands (GDNF and NTN); components of another signaling pathway (EDNRB, EDN3, ECE-1); and the transcription factor, SOX10, have been identified in HSCR patients. A subset of these mutations is associated with anomalies of pigmentation and/or hearing loss. For almost every HSCR gene, incomplete penetrance of the HSCR phenotype has been observed, probably due to genetic modifier loci. Thus, HSCR has become a model of a complex polygenic disorder in which the interplay of different genes is currently being elucidated.
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Affiliation(s)
- M A Parisi
- Department of Pediatrics, Children's Hospital and Regional Medical Center, Seattle, Washington, USA
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O'Regan S, Traiffort E, Ruat M, Cha N, Compaore D, Meunier FM. An electric lobe suppressor for a yeast choline transport mutation belongs to a new family of transporter-like proteins. Proc Natl Acad Sci U S A 2000; 97:1835-40. [PMID: 10677542 PMCID: PMC26522 DOI: 10.1073/pnas.030339697] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Choline is an important metabolite in all cells due to the major contribution of phosphatidylcholine to the production of membranes, but it takes on an added role in cholinergic neurons where it participates in the synthesis of the neurotransmitter acetylcholine. We have cloned a suppressor for a yeast choline transport mutation from a Torpedo electric lobe yeast expression library by functional complementation. The full-length clone encodes a protein with 10 putative transmembrane domains, two of which contain transporter-like motifs, and whose expression increased high-affinity choline uptake in mutant yeast. The gene was called CTL1 for its choline transporter-like properties. The homologous rat gene, rCTL1, was isolated and found to be highly expressed as a 3. 5-kb transcript in the spinal cord and brain and as a 5-kb transcript in the colon. In situ hybridization showed strong expression of rCTL1 in motor neurons and oligodendrocytes and to a lesser extent in various neuronal populations throughout the rat brain. High levels of rCTL1 were also identified in the mucosal cell layer of the colon. Although the sequence of the CTL1 gene shows clear homology with a single gene in Caenorhabditis elegans, several homologous genes are found in mammals (CTL2-4). These results establish a new family of genes for transporter-like proteins in eukaryotes and suggest that one of its members, CTL1, is involved in supplying choline to certain cell types, including a specific subset of cholinergic neurons.
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Affiliation(s)
- S O'Regan
- Biologie de la Neurotransmission and Junior group ATIPE, Laboratoire de Neurobiologie Cellulaire et Moléculaire (Unité 9040), Centre National de la Recherche Scientifique, 1 avenue de la Terrasse, 91198, Gif-sur-Yvette, France.
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Colombo R. Age estimate of the N370S mutation causing Gaucher disease in Ashkenazi Jews and European populations: A reappraisal of haplotype data. Am J Hum Genet 2000; 66:692-7. [PMID: 10677327 PMCID: PMC1288120 DOI: 10.1086/302757] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/1999] [Accepted: 11/11/1999] [Indexed: 11/03/2022] Open
Abstract
The N370S mutation at the GBA locus on human chromosome 1q21, which causes Gaucher disease (GD), has a high frequency in the Ashkenazim and is the second-most-widespread GD mutation in the European non-Jewish population. A common ancient origin for the N370S mutation in the Ashkenazi Jewish and Spanish populations has been proposed on the basis of both a similar haplotype for associated markers and an age estimate that suggests that this mutation appeared several thousand years ago. However, a reappraisal of haplotype data, using the Risch formula properly along with a Luria-Delbrück setting of the genetic clock, allows identification of the likely origin of the N370S mutation in Ashkenazi Jews between the 11th and 13th centuries. This result is consistent with the estimated ages of other mutations that are frequent among Ashkenazim, with the exception of type II (Glu117Stop) factor XI deficiency, which is deemed to be >3000 years old, predating the separation of the Ashkenazi and Iraqi Jews. The present finding supports the hypothesis of a more recent origin for the N370S mutation and is consistent with both a founder chromosome transfer from Ashkenazim who assimilated in some European populations and a non-Jewish origin of the European N370S-bearing chromosomes.
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Affiliation(s)
- R Colombo
- Human Biology and Genetics Research Unit, Department of Psychology, Catholic University of the Sacred Heart, Largo A. Gemelli 1, I-20123 Milan, Italy.
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Chadwick BP, Gill S, Leyne M, Mull J, Liebert CB, Robbins CM, Pinkett HW, Makalowska I, Maayan C, Blumenfeld A, Axelrod FB, Brownstein M, Slaugenhaupt SA. Cloning, genomic organization and expression of a putative human transmembrane protein related to the Caenorhabditis elegans M01F1.4 gene. Gene 1999; 240:67-73. [PMID: 10564813 DOI: 10.1016/s0378-1119(99)00432-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A novel human transcript CG-2 (C9ORF5), was isolated from the familial dysautonomia candidate region on 9q31 using a combination of cDNA selection and exon trapping. CG-2 was detected as a relatively abundant 8kb transcript in all adult and fetal tissues with the exception of adult thymus. Genomic analysis of CG-2 identified 18 exons that span more than 110kb. The gene encodes a 911-amino-acid protein with a predicted molecular weight of 101kDa and a hypothetical pI of 9.03. Sequence analysis of CG-2 indicates that it is likely to encode a transmembrane protein. Here, we assess CG-2 as a candidate for familial dysautonomia.
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MESH Headings
- Adult
- Amino Acid Sequence
- Animals
- Brain/embryology
- Brain/metabolism
- Caenorhabditis elegans/genetics
- Cell Line
- Chromosome Mapping
- Chromosomes, Human, Pair 9/genetics
- Cloning, Molecular
- Cricetinae
- DNA/chemistry
- DNA/genetics
- DNA Mutational Analysis
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Databases, Factual
- Dysautonomia, Familial/genetics
- Expressed Sequence Tags
- Gene Expression
- Gene Expression Regulation, Developmental
- Genes/genetics
- Genes, Helminth/genetics
- Humans
- Hybrid Cells
- Membrane Proteins/genetics
- Mice
- Molecular Sequence Data
- Rats
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
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Affiliation(s)
- B P Chadwick
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, MA, USA
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Abstract
Great advances have been made in understanding the molecular basis of Charcot-Marie-Tooth disease (CMT) and related neuropathies, namely Dejerine-Sottas disease (DSD), hereditary neuropathy with liability to pressure palsies (HNPP) and congenital hypomyelination (CH). The number of newly uncovered mutations and identified genetic loci is rapidly increasing, and, as a consequence, the classification of these disorders is becoming more complicated. Molecular genetics, animal models, and transfected cell studies are shedding light on function and dysfunction of proteins involved in hereditary myelinopathies-peripheral myelin protein 22 (PMP22), myelin protein zero (PO), connexin 32 (Cx32), and early growth response 2 (EGR2). Gene dosage effect, loss of function, gain of toxic function, and dominant negative effect are possible mechanisms whereby different gene mutations may exert their detrimental action on peripheral nerves. A tentative rational approach to clinical and molecular diagnosis based on genotype-phenotype correlation analysis is described.
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Affiliation(s)
- D Pareyson
- Department of Neurology, Istituto Nazionale Neurologico "C.Besta," Via Celoria 11, 20133 Milan, Italy.
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Chadwick BP, Mull J, Helbling LA, Gill S, Leyne M, Robbins CM, Pinkett HW, Makalowska I, Maayan C, Blumenfeld A, Axelrod FB, Brownstein M, Gusella JF, Slaugenhaupt SA. Cloning, mapping, and expression of two novel actin genes, actin-like-7A (ACTL7A) and actin-like-7B (ACTL7B), from the familial dysautonomia candidate region on 9q31. Genomics 1999; 58:302-9. [PMID: 10373328 DOI: 10.1006/geno.1999.5848] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Two novel human actin-like genes, ACTL7A and ACTL7B, were identified by cDNA selection and direct genomic sequencing from the familial dysautonomia candidate region on 9q31. ACTL7A encodes a 435-amino-acid protein (predicted molecular mass 48.6 kDa) and ACTL7B encodes a 415-amino-acid protein (predicted molecular mass 45. 2 kDa) that show greater than 65% amino acid identity to each other. Genomic analysis revealed ACTL7A and ACTL7B to be intronless genes contained on a common 8-kb HindIII fragment in a "head-to-head" orientation. The murine homologues were cloned and mapped by linkage analysis to mouse chromosome 4 in a region of gene order conserved with human chromosome 9q31. No recombinants were observed between the two genes, indicating a close physical proximity in mouse. ACTL7A is expressed in a wide variety of adult tissues, while the ACTL7B message was detected only in the testis and, to a lesser extent, in the prostate. No coding sequence mutations, genomic rearrangements, or differences in expression were detected for either gene in familial dysautonomia patients.
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MESH Headings
- Actins/genetics
- Adult
- Amino Acid Sequence
- Animals
- Blotting, Northern
- Chromosome Mapping
- Chromosomes/genetics
- Chromosomes, Human, Pair 9/genetics
- Cloning, Molecular
- DNA/chemistry
- DNA/genetics
- DNA/isolation & purification
- DNA Mutational Analysis
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Dysautonomia, Familial/genetics
- Female
- Gene Expression
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Molecular Sequence Data
- Muridae
- RNA/genetics
- RNA/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
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Affiliation(s)
- B P Chadwick
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
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