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Slovis N, Irvin L. Neonates and Periparturient Mares: Tips and Tricks for Diagnosis and Management. Vet Clin North Am Equine Pract 2023:S0749-0739(23)00025-1. [PMID: 37258390 DOI: 10.1016/j.cveq.2023.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
Colic is a common presenting complaint in foals. Unfortunately, evaluation of foals with colic can be difficult due to the common clinical presentation of acute abdominal pain attributable to a wide variety of disorders and a broad range of etiologies. Similar to foals, colic is one of the most common diseases of pregnant and periparturient mares. Several conditions are unique or occur more commonly in broodmares. This article reviews the most commonly encountered types of colic events in neonatal foals and periparturient mares, how to correctly diagnose these conditions, as well as details concerning appropriate medical management and/or surgical intervention.
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Affiliation(s)
- Nathan Slovis
- Hagyard Equine Medical Institute, McGee Medical Center, 4250 Ironworks Pike, Lexington, KY 40511, USA.
| | - Leci Irvin
- Hagyard Equine Medical Institute, McGee Medical Center, 4250 Ironworks Pike, Lexington, KY 40511, USA
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Analysis of the Effect of Laparoscopic and Open Surgical Treatment in Children with Congenital Megacolon. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2022; 2022:2669294. [PMID: 35720885 PMCID: PMC9200504 DOI: 10.1155/2022/2669294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/23/2022] [Accepted: 05/16/2022] [Indexed: 11/18/2022]
Abstract
In this paper, we have compared and analyzed the effect of laparoscopic and open surgical treatments in children with congenital megacolon. To address this, a total of 64 children with congenital megacolon who underwent surgery in the hospital, particularly from April 2014 to December 2020, were selected as the research objects. They were divided into control and observation groups by the random number table method, with 32 cases in each group. The control and observation groups were treated with open surgical and laparoscopic treatments, respectively. The treatment effects of the two groups were compared. The enema time, operation time, blood loss, anal defecation time, and duration of postoperative hospital stay of the observation group were lower than those of the control group. The comparison between the two groups was statistically significant (P < 0.05). There was no significant difference in CRP and WBC between the two groups before surgery (P > 0.05). The CRP level and WBC of the two groups were both increased after operation, the CRP level of the observation group was lower than that of the control group, the difference was statistically significant (P < 0.05), the WBC of the two groups was not statistically significant (P > 0.05). The rate of excellent and good defecation in the observation group on the 7th day after surgery was higher than that in the control group, and the difference was statistically significant (P < 0.05). There was no significant difference in Krickenbeck scores between the two groups before surgery (P > 0.05); 6 months after the surgery, the score of Krickenbeck in both groups increased, and that of the observation group was higher than that of the control group, indicating a difference in the overall score (P < 0.05). The total complication rate within 7 days after surgery in the observation group was lower than that in the control group, and the difference was not statistically significant (P > 0.05). Laparoscopic treatment of congenital megacolon could improve surgical indicators and reduce stress response in children, improve defecation and anal function, reduce the risk of complications, and promote recovery.
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Mutations in rhodopsin, endothelin B receptor, and CC chemokine receptor 5 in large animals: Modeling human diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 189:155-178. [PMID: 35595348 DOI: 10.1016/bs.pmbts.2022.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of cell membrane receptors involved in modulating almost all physiological processes by transducing extracellular signals into the cytoplasm. Dysfunctions of GPCR-regulated signaling result in diverse human diseases, making GPCRs the most popular drug targets for human medicine. Large animals share higher similarities (in physiology and metabolism) with humans than rodents. Similar to findings in human genetics, diverse diseases caused by mutations in GPCR genes have also been discovered in large animals. Rhodopsin, endothelin B receptor, and CC chemokine receptor type 5 have been shown to be involved in human retinitis pigmentosa, Hirschsprung disease, and HIV infection/AIDS, respectively, and several mutations of these GPCRs have also been identified from large animals. The large animals with naturally occurring mutations of these GPCRs provide an opportunity to gain a better understanding of the pathogenesis of human diseases, and can be used for preclinical trials of therapies for human diseases. In this review, we aim to summarize the naturally occurring mutations of these three GPCRs in large animals and humans.
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Savel S, Sombé P. Are dogs with congenital hearing and/or vision impairments so different from sensory normal dogs? A survey of demographics, morphology, health, behaviour, communication, and activities. PLoS One 2020; 15:e0230651. [PMID: 32886662 PMCID: PMC7473589 DOI: 10.1371/journal.pone.0230651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/04/2020] [Indexed: 12/02/2022] Open
Abstract
The births of domestic dogs with pigment deletion and associated congenital hearing and/or vision impairments are increasing, as a result of mutations of certain genes expressing popular coat colour patterns (Merle, piebald, Irish spotting). The future of these dogs is often pessimistic (early euthanasia or placement in rescues/fosters, lack of interactions and activities for adults). These pessimistic scenarios result from popular assumptions predicting that dogs with congenital hearing/vision impairments exhibit severe Merle-related health troubles (cardiac, skeletal, neurological), impairment-related behavioural troubles (aggressiveness, anxiety), and poor capacities to communicate, to be trained, and to be engaged in leisure or work activities. However, there is no direct scientific testing, and hence no evidence or refutation, of these assumptions. We therefore addressed an online questionnaire to owners of 223 congenitally sensory impaired (23 vision impaired, 63 hearing impaired, 137 hearing and vision impaired) and 217 sensory normal dogs from various countries. The sensory normal cohort was matched in age, lifetime with owner, breed and sex with the sensory impaired cohort, and was used as a baseline. The questionnaire assessed demographics, morphology, sensory impairments, health and behavioural troubles, activities, and dog-owner communication. Most hearing and/or vision impaired dogs exhibited abnormal pigment deletion in their coat and irises. Vision impaired dogs additionally exhibited ophthalmic abnormalities typically related to Merle. The results are opposed to all above-listed assumptions, except for neurological troubles, which were more frequently reported in sensory impaired dogs. However, we suggest that this finding could be partially accounted for by a lack of diagnosis of breed-related drug sensitivity and impairment-related compulsive behaviours. Results about communication and activities are particularly optimistic. The need for future studies of numerous dogs from various breeds tested for Merle, piebald and medical-drug-resistance genes, and the beneficial effects that present and future research may have on the future of sensory impaired dogs, are discussed.
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Affiliation(s)
- Sophie Savel
- Aix Marseille University, CNRS, Centrale Marseille, LMA UMR 7031, Marseille, France
- * E-mail:
| | - Patty Sombé
- Non-profit organisation “Blanc Comme Neige”, Pont d’Ouilly, France
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Abstract
Neurologic disease in horses can be particularly challenging to diagnose and treat. These diseases can result in economic losses, emotional distress to owners, and injury to the horse or handlers. To date, there are 5 neurologic diseases caused by known genetic mutations and several more are suspected to be heritable: lethal white foal syndrome, lavender foal syndrome, cerebellar abiotrophy, occipitoatlantoaxial malformation, and Friesian hydrocephalus. Genetic testing allows owners, breeders, and veterinarians to make informed decisions when selecting dams and sires for breeding or deciding the treatment or prognosis of a neurologic animal.
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Affiliation(s)
- Lisa Edwards
- Department of Veterinary Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, Room 4206 Vet Med 3A One Shields Avenue, Davis, CA 95616, USA
| | - Carrie J Finno
- Department of Veterinary Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, Room 4206 Vet Med 3A One Shields Avenue, Davis, CA 95616, USA.
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Gianino GM, Valberg SJ, Perumbakkam S, Henry ML, Gardner K, Penedo C, Finno CJ. Prevalence of the E321G MYH1 variant for immune-mediated myositis and nonexertional rhabdomyolysis in performance subgroups of American Quarter Horses. J Vet Intern Med 2019; 33:897-901. [PMID: 30623495 PMCID: PMC6430863 DOI: 10.1111/jvim.15393] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 11/16/2018] [Indexed: 01/30/2023] Open
Abstract
Background Immune‐mediated myositis (IMM) in American Quarter Horses (QHs) causes acute muscle atrophy and lymphocytic infiltration of myofibers. Recently, an E321G mutation in a highly conserved region of the myosin heavy chain 1 (MYH1) gene was associated with susceptibility to IMM and nonexertional rhabdomyolysis. Objectives To estimate prevalence of the E321G MYH1 variant in the QH breed and performance subgroups. Animals Three‐hundred seven elite performance QHs and 146 random registered QH controls. Methods Prospective genetic survey. Elite QHs from barrel racing, cutting, halter, racing, reining, Western Pleasure, and working cow disciplines and randomly selected registered QHs were genotyped for the E321G MYH1 variant and allele frequencies were calculated. Results The E321G MYH1 variant allele frequency was 0.034 ± 0.011 in the general QH population (6.8% of individuals in the breed) and the highest among the reining (0.135 ± 0.040; 24.3% of reiners), working cow (0.085 ± 0.031), and halter (0.080 ± 0.027) performance subgroups. The E321G MYH1 variant was present in cutting (0.044 ± 0.022) and Western Pleasure (0.021 ± 0.015) QHs at lower frequency and was not observed in barrel racing or racing QHs. Conclusions and Clinical Importance Knowing that reining and working cow QHs have the highest prevalence of the E321G MYH1 variant and that the variant is more prevalent than the alleles for hereditary equine regional dermal asthenia and hyperkalemic periodic paralysis in the general QH population will guide the use of genetic testing for diagnostic and breeding purposes.
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Affiliation(s)
- Giuliana M Gianino
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California
| | - Stephanie J Valberg
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Sudeep Perumbakkam
- McPhail Equine Neuromuscular Diagnostic and Research Laboratory, McPhail Equine Performance Center, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Marisa L Henry
- McPhail Equine Neuromuscular Diagnostic and Research Laboratory, McPhail Equine Performance Center, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Keri Gardner
- McPhail Equine Neuromuscular Diagnostic and Research Laboratory, McPhail Equine Performance Center, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Cecilia Penedo
- Service Department, Veterinary Genetics Lab (Penedo), University of California, Davis, California
| | - Carrie J Finno
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California
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Sánchez-Guerrero MJ, Negro-Rama S, Demyda-Peyras S, Solé-Berga M, Azor-Ortiz PJ, Valera-Córdoba M. Morphological and genetic diversity of Pura Raza Español horse with regard to the coat colour. Anim Sci J 2018; 90:14-22. [PMID: 30467923 DOI: 10.1111/asj.13102] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 07/04/2018] [Accepted: 07/13/2018] [Indexed: 11/27/2022]
Abstract
Gene mutations influencing melanocytes also impact on physiological and behavioural functions. In this study, we investigated their association with four different coat colours in the Pura Raza Español (PRE) horse using morphological traits and molecular datasets. Four different subpopulations were identified according to individual coat colour: grey, bay, chestnut and black. Coat colour significantly associated with morphological measurements. Observed and expected heterozygosity values were low in grey compared with the other three subpopulations, suggesting the presence of unique ancestral alleles probably arisen by genetic drift and selection mechanism effects. Nei's distance demonstrated a clear division among subpopulations, the grey being the most divergent group. Gene flow estimates were similar, showing the lowest values in grey. Divergence times among subpopulations assessed with the average square distance suggested that grey was the original PRE population which diverged from bay, chestnut and black. Our results also demonstrated a clear morphological differentiation according to coat colour. The close genetic structure of bay and chestnut PRE subpopulations and the clear differences in most morphological traits of grey and chestnut PRE mares would suggest the pleiotropic effect of genomic regions determining coat colour in horses. However, further analysis including genomic information would be necessary to elucidate the mechanisms involved.
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Affiliation(s)
| | - Sara Negro-Rama
- Departamento de Ciencias Agroforestales, ETSIA, Universidad de Sevilla, Sevilla, España
| | - Sebastián Demyda-Peyras
- Facultad de Ciencias Veterinarias, IGEVET-Instituto de Genética Veterinaria "Ing. Fernando N. Dulout" (UNLP-CONICET LA PLATA), Universidad Nacional de La Plata, La Plata, Argentina
| | - Marina Solé-Berga
- Unit of Animal Genomics, GIGA-R & Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Pedro J Azor-Ortiz
- Departamento de Ciencias Agroforestales, ETSIA, Universidad de Sevilla, Sevilla, España
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Bondurand N, Dufour S, Pingault V. News from the endothelin-3/EDNRB signaling pathway: Role during enteric nervous system development and involvement in neural crest-associated disorders. Dev Biol 2018; 444 Suppl 1:S156-S169. [PMID: 30171849 DOI: 10.1016/j.ydbio.2018.08.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/27/2018] [Accepted: 08/27/2018] [Indexed: 01/08/2023]
Abstract
The endothelin system is a vertebrate-specific innovation with important roles in regulating the cardiovascular system and renal and pulmonary processes, as well as the development of the vertebrate-specific neural crest cell population and its derivatives. This system is comprised of three structurally similar 21-amino acid peptides that bind and activate two G-protein coupled receptors. In 1994, knockouts of the Edn3 and Ednrb genes revealed their crucial function during development of the enteric nervous system and melanocytes, two neural-crest derivatives. Since then, human and mouse genetics, combined with cellular and developmental studies, have helped to unravel the role of this signaling pathway during development and adulthood. In this review, we will summarize the known functions of the EDN3/EDNRB pathway during neural crest development, with a specific focus on recent scientific advances, and the enteric nervous system in normal and pathological conditions.
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Affiliation(s)
- Nadege Bondurand
- Laboratory of Embryology and Genetics of Congenital Malformations, INSERM U1163, Institut Imagine, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Institut Imagine, Paris, France.
| | - Sylvie Dufour
- INSERM, U955, Equipe 06, Créteil 94000, France; Université Paris Est, Faculté de Médecine, Créteil 94000, France
| | - Veronique Pingault
- Laboratory of Embryology and Genetics of Congenital Malformations, INSERM U1163, Institut Imagine, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Institut Imagine, Paris, France; Service de Génétique Moléculaire, Hôpital Necker-Enfants Malades, Assistance Publique - Hôpitaux de Paris, Paris, France
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Validation of high-resolution melting analysis as a diagnostic tool for endothelin receptor B mutation in American Paint horses and allele frequency estimation. Mol Cell Probes 2018; 41:52-56. [PMID: 30096357 DOI: 10.1016/j.mcp.2018.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/17/2018] [Accepted: 08/07/2018] [Indexed: 11/21/2022]
Abstract
Overo lethal white foal syndrome (OLWFS) is a genetic disorder caused by a dinucleotide mutation in the endothelin receptor type B (EDNRB) gene leading to the death of affected foals shortly after birth. The use of rapid and reliable genetic testing is imperative for the early diagnosis of the mutation avoiding, therefore, either additional suffering or the production of affected animals. In the present study, we developed and validated a high-resolution melting (HRM) genotyping assay to detect the OLWFS causative mutation, and we also determined the frequency of heterozygotes among American Paint horses in Brazil. The HRM genotyping assay resulted in a high sensitivity, specificity, and positive and negative predictive values. The overall estimated frequency of heterozygotes was 21.6%; however, this frequency increased to 89.5% when considering only overo horses. The HRM assay optimized here was a reliable and suitable method for the detection of the dinucleotide mutation observed in the EDNRB gene resulting in a fast, accurate, and precise diagnostic tool. The causative gene mutation of OLWFS is present in heterozygosity in the American Paint Horse population in Brazil and is highly frequent among overo horses.
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Ayala-Valdovinos MA, Galindo-García J, Sánchez-Chiprés D, Duifhuis-Rivera T. New test for endothelin receptor type B (EDNRB) mutation genotyping in horses. Mol Cell Probes 2016; 30:182-4. [DOI: 10.1016/j.mcp.2016.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 03/18/2016] [Accepted: 03/24/2016] [Indexed: 10/22/2022]
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Extrinsic innervation of ileum and pelvic flexure of foals with ileocolonic aganglionosis. Cell Tissue Res 2016; 366:13-22. [DOI: 10.1007/s00441-016-2422-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 05/02/2016] [Indexed: 12/20/2022]
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Abstract
Horses are valued for the beauty and variety of colouration and coat patterning. To date, eleven different genes have been characterized that contribute to the variation observed in the horse. Unfortunately, mutations involving pigmentation often lead to deleterious effects in other systems, some of which have been described in the horse. This review focuses on six such pleiotropic effects or associations with pigmentation genes. These include neurological defects (lethal white foal syndrome and lavender foal syndrome), hearing defects, eye disorders (congenital stationary night blindness and multiple congenital ocular anomalies), as well as horse-specific melanoma. The pigmentation phenotype, disorder phenotype, mode of inheritance, genetic or genomic methods utilized to identify the genes involved and, if known, the causative mutations, molecular interactions and other susceptibility loci are discussed. As our understanding of pigmentation in the horse increases, through the use of novel genomic tools, we are likely to unravel yet unknown pleiotropic effects and determine additional interactions between previously discovered loci.
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Affiliation(s)
- R R Bellone
- Department of Biology, University of Tampa, 401 W. Kennedy Blvd., Tampa, FL 33606, USA.
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Muniz E, Lobo Ladd AAB, Lobo Ladd FV, da Silva AAP, Kmit FV, Borges AS, Teixeira R, da Mota LSLS, Belli CB, de Zoppa ALV, da Silva LCLC, de Melo MP, Coppi AA. 3-D technology used to accurately understand equine ileocolonic aganglionosis. Cells Tissues Organs 2013; 198:160-8. [PMID: 23886660 DOI: 10.1159/000353218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2013] [Indexed: 11/19/2022] Open
Abstract
Ileocolonic aganglionosis (ICA) is the congenital and hereditary absence of neurons that constitute the enteric nervous system and has been described in various species including humans - Hirschsprung's disease - and horses - overo lethal white syndrome (OLWS). Hirschsprung's disease affects circa 1 in 5,000 live births. At best, this disease means an inability to absorb nutrients from food (humans). At worse, in horses, it always means death. Despite our general understanding of the functional mechanisms underlying ICA, there is a paucity of reliable quantitative information about the structure of myenteric and submucosal neurons in healthy horses and there are no studies on horses with ICA. In light of these uncertainties, we have used design-based stereology to describe the 3-D structure - total number and true size - of myenteric and submucosal neurons in the ileum of ICA horses. Our study has shown that ICA affects all submucosal neurons and 99% of myenteric neurons. The remaining myenteric neurons (0.56%) atrophy immensely, i.e. 63.8%. We believe this study forms the basis for further research, assessing which subpopulation of myenteric neurons are affected by ileocolonic aganglionosis, and we would like to propose a new nomenclature to distinguish between a complete absence of neurons - aganglionosis - and a weaker form of the disease which we suggest naming 'hypoganglionosis'. Our results are a step forward in understanding this disease structurally.
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Affiliation(s)
- Eliane Muniz
- Laboratory of Experimental Neurogastroenterology, Universidade Paranaense, Umuarama, Brazil
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Extensive Myenteric Ganglionitis in a Case of Equine Chronic Intestinal Pseudo-obstruction Associated with EHV-1 Infection. J Comp Pathol 2013; 148:289-93. [DOI: 10.1016/j.jcpa.2012.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/06/2012] [Accepted: 07/12/2012] [Indexed: 12/19/2022]
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Pauciullo A, Fleck K, Lühken G, Di Berardino D, Erhardt G. Dual-Color High-Resolution Fiber-FISH Analysis on Lethal White Syndrome Carriers in Sheep. Cytogenet Genome Res 2013; 140:46-54. [DOI: 10.1159/000350786] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2013] [Indexed: 11/19/2022] Open
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Lühken G, Fleck K, Pauciullo A, Huisinga M, Erhardt G. Familiar hypopigmentation syndrome in sheep associated with homozygous deletion of the entire endothelin type-B receptor gene. PLoS One 2012; 7:e53020. [PMID: 23300849 PMCID: PMC3534075 DOI: 10.1371/journal.pone.0053020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 11/22/2012] [Indexed: 11/24/2022] Open
Abstract
In humans, rodents and horses, pigmentary anomalies in combination with other disorders, notably intestinal aganglionosis, are associated with variants of the endothelin type-B receptor gene (EDNRB). In an inbred Cameroon sheep flock, five white lambs with light blue eyes were sired from the same ram and died within a few hours up to a few days after birth, some of them with signs of intestinal obstruction. The aim of this study was to investigate if the observed hypopigmentation and a possible lethal condition were associated with a molecular change at the ovine EDNRB locus, and to check if such a genetic alteration also occurs in other Cameroon sheep flocks. Sequence analysis revealed a deletion of about 110 kb on sheep chromosome 10, comprising the entire EDNRB gene, on both chromosomes in the two available hypopigmented lambs and on a single chromosome in the two dams and three other unaffected relatives. This micro-chromosomal deletion was also confirmed by quantitative real-time PCR and by fluorescence in situ hybridization. Genotyping of a total of 127 Cameroon sheep in 7 other flocks by duplex PCR did not identify additional carriers of the deletion. Although both hypopigmented lambs available for post-mortem examination had a considerably dilated cecum and remaining meconium, histopathological examination of intestinal samples showed morphologically normal ganglion cells in appropriate number and distribution. This is to our knowledge the first description of an ENDRB gene deletion and associated clinical signs in a mammalian species different from humans and rodents. In humans and rats it is postulated that the variable presence and severity of intestinal aganglionosis and other features in individuals with EDNRB deletion is due to a variable genetic background and multiple gene interactions. Therefore the here analyzed sheep are a valuable animal model to test these hypotheses in another species.
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Affiliation(s)
- Gesine Lühken
- Department of Animal Breeding and Genetics, Justus-Liebig University of Giessen, Giessen, Germany.
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Abstract
The objective of this review is to introduce equine clinicians to the rapidly evolving field of clinical genomics with a vision of improving the health and welfare of the domestic horse. For 15 years a consortium of veterinary geneticists and clinicians has worked together under the umbrella of The Horse Genome Project. This group, encompassing 22 laboratories in 12 countries, has made rapid progress, developing several iterations of linkage, physical and comparative gene maps of the horse with increasing levels of detail. In early 2006, the research was greatly facilitated when the US National Human Genome Research Institute of the National Institutes of Health added the horse to the list of mammalian species scheduled for whole genome sequencing. The genome of the domestic horse has now been sequenced and is available to researchers worldwide in publicly accessible databases. This achievement creates the potential for transformative change within the horse industry, particularly in the fields of internal medicine, sports medicine and reproduction. The genome sequence has enabled the development of new genome-wide tools and resources for studying inherited diseases of the horse. To date, researchers have identified 11 mutations causing 10 clinical syndromes in the horse. Testing is commercially available for all but one of these diseases. Future research will probably identify the genetic bases for other equine diseases, produce new diagnostic tests and generate novel therapeutics for some of these conditions. This will enable equine clinicians to play a critical role in ensuring the thoughtful and appropriate application of this knowledge as they assist clients with breeding and clinical decision-making.
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Affiliation(s)
- M M Brosnahan
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, New York, USA
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21
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De Ceulaer KMG, Van Ginneken CJD, Philips WA, Weyns A. Interstitial Cells of Cajal and their Role in Veterinary Gastrointestinal Pathologies. Anat Histol Embryol 2007; 36:300-10. [PMID: 17617109 DOI: 10.1111/j.1439-0264.2007.00766.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study highlights the importance of interstitial cells of Cajal (ICs) in gastrointestinal disease. Human research is already considering IC pathologies but in veterinary research IC pathologies are rarely studied. Nevertheless, recent studies of ICs show a growing interest in the pathophysiology of gastrointestinal diseases and emphasize the consideration of this cell type in the pathophysiology of veterinary gastrointestinal malfunctions.
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Affiliation(s)
- K M G De Ceulaer
- Laboratory of Veterinary Anatomy and Embryology, Department of Veterinary Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Antwerp University, Universiteitsplein 1, 2610 Wilrijk, Belgium.
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Abstract
AIM This review highlights the relevance of the neural crest (NC) as a developmental control mechanism involved in several pediatric surgical conditions and the investigative interest of following some of its known signaling pathways. METHODS The participation of the NC in facial clefts, ear defects, branchial fistulae and cysts, heart outflow tract and aortic arch anomalies, pigmentary disorders, abnormal enteric innervation, neural tumors, hemangiomas, and vascular anomalies is briefly reviewed. Then, the literature on clinical and experimental esophageal atresia-tracheoesophageal fistula (EA-TEF) and congenital diaphragmatic hernia (CDH) is reviewed for the presence of associated NC defects. Finally, some of the molecular signaling pathways involved in both conditions (sonic hedgehog, Hox genes, and retinoids) are summarized. RESULTS The association of facial, cardiovascular, thymic, parathyroid, and C-cell defects together with anomalies of extrinsic and intrinsic esophageal innervation in babies and/or animals with both EA-TEF and CDH strongly supports the hypothesis that NC is involved in the pathogenesis of these malformative clusters. On the other hand, both EA-TEF and CDH are observed in mice mutant for genes involved in the previously mentioned signaling pathways. CONCLUSIONS The investigation of NC-related molecular pathogenic pathways involved in malformative associations like EA-TEF and CDH that are induced by chromosomal anomalies, chemical teratogens, and engineered mutations is a promising way of clarifying why and how some pediatric surgical conditions occur. Pediatric surgeons should be actively involved in these investigations.
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MESH Headings
- Abnormalities, Multiple/embryology
- Abnormalities, Multiple/physiopathology
- Abnormalities, Multiple/surgery
- Blood Vessels/abnormalities
- Branchial Region/abnormalities
- Cardiovascular Abnormalities/embryology
- Cardiovascular Abnormalities/physiopathology
- Cell Lineage
- Cell Movement
- Child
- Child, Preschool
- Enteric Nervous System/abnormalities
- Esophageal Atresia/embryology
- Esophageal Atresia/physiopathology
- Esophageal Atresia/surgery
- Face/abnormalities
- Genes, Homeobox
- Hedgehog Proteins/physiology
- Hernia, Diaphragmatic/embryology
- Hernia, Diaphragmatic/physiopathology
- Hernia, Diaphragmatic/surgery
- Hernias, Diaphragmatic, Congenital
- Homeodomain Proteins/physiology
- Humans
- Infant
- Infant, Newborn
- Neoplasms/etiology
- Neural Crest/physiopathology
- Patched Receptors
- Pigmentation Disorders/etiology
- Receptors, Cell Surface/physiology
- Receptors, G-Protein-Coupled/physiology
- Receptors, Retinoic Acid/physiology
- Signal Transduction
- Smoothened Receptor
- Syndrome
- Transcription Factors/physiology
- Tretinoin/physiology
- Zinc Finger Protein GLI1
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Affiliation(s)
- Juan A Tovar
- Departamento de Cirugía Pediátrica, Hospital Universitario La Paz, 28046 Madrid, Spain.
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23
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Abstract
Hirschsprung's disease constitutes a neural crest stem cell disorder (neurocristopathy) which is caused by absent or malfunctional intestinal intramural ganglion cells. The rostral extension of the aganglionic segment is variable. Hirschsprung's disease can be classified into type 1 (short segment) and type 2 (long segment) forms. It is limited to the gastrointestinal tract, but may occur in the syndromal context of manifold genetic diseases in 12% of patients. The prevalence is 1:5,000 with a distinct male predominance of 4-5:1. Numerous genes and non-coding polymorphous DNA sequence variants are involved in the pathogenesis of Hirschsprung's disease. The most important gene is RET. Susceptibility loci on 3p21, 9q31 and 19q12 interact with this gene. Downstream of RET, two new genes, GALNACT-2 and RASGEF1A, have also been identified. A recently described, frequent, non-coding RET variant, RET+3, is significantly associated with susceptibility to Hirschsprung's disease and carries a 20-fold increased risk of contracting the disease compared to rarer alleles.
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Affiliation(s)
- E Passarge
- Institut für Humangenetik, Universitätsklinikum Essen, 45122 Essen, Germany.
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24
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Masiakos PT, Ein SH. The History of Hirschsprung’s Disease: Then and Now. SEMINARS IN COLON AND RECTAL SURGERY 2006. [DOI: 10.1053/j.scrs.2006.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Affiliation(s)
- A Mortell
- Children's Research Centre, Our Lady's Hospital for Sick Children, Crumlin, Dublin 12, Ireland
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26
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Abstract
This review, which is presented in two parts, summarizes and synthesizes current views on the genetic, molecular, and cell biological underpinnings of the early embryonic phases of enteric nervous system (ENS) formation and its defects. In the first part, we describe the critical features of two principal abnormalities of ENS development: Hirschsprung's disease (HSCR) and intestinal neuronal dysplasia type B (INDB) in humans, and the similar abnormalities in animals. These represent the extremes of the diagnostic spectrum: HSCR has agreed and unequivocal diagnostic criteria, whereas the diagnosis and even existence of INDB as a clinical entity is highly controversial. The difficulties in diagnosis and treatment of both these conditions are discussed. We then review the genes now known which, when mutated or deleted, may cause defects of ENS development. Many of these genetic abnormalities in animal models give a phenotype similar or identical to HSCR, and were discovered by studies of humans and of mouse mutants with similar defects. The most important of these genes are those coding for molecules in the GDNF intercellular signaling system, and those coding for molecules in the ET-3 signaling system. However, a range of other genes for different signaling systems and for transcription factors also disturb ENS formation when they are deleted or mutated. In addition, a large proportion of HSCR cases have not been ascribed to the currently known genes, suggesting that additional genes for ENS development await discovery.
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Affiliation(s)
- Donald Newgreen
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, 3052, Victoria, Australia
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27
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Alhaidari, Olivry, Ortonne. Melanocytogenesis and melanogenesis: genetic regulation and comparative clinical diseases. Vet Dermatol 2002; 10:3-16. [DOI: 10.1046/j.1365-3164.1999.00132.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Alhaidari
- Clinique Vétérinaire, Cidex 248, R. N. 85, 06330‐Roquefort les Pins, France,
| | - Olivry
- College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough street, Raleigh, NC 27606, USA,
| | - Ortonne
- Hopital de l’Archet II‐Service de Dermatologie, 151, route Saint Antoine de Ginestière‐BP 79, 06202 Nice Cedex 3, France
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28
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Santschi EM, Vrotsos PD, Purdy AK, Mickelson JR. Incidence of the endothelin receptor B mutation that causes lethal white foal syndrome in white-patterned horses. Am J Vet Res 2001; 62:97-103. [PMID: 11197568 DOI: 10.2460/ajvr.2001.62.97] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine incidence of the Ile118Lys endothelin receptor B (EDNRB) mutation responsible for overo lethal white syndrome (OLWS) and its association with specific types of white patterning. ANIMALS 945 horses of white-patterned bloodlines and 55 solid-colored horses of other breeds. PROCEDURE Horses were genotyped by use of allele-specific polymerase chain reaction to determine incidence of the Ile118Lys EDNRB mutation. RESULTS Genotypes detected were homozygous Ile118, homozygous Lys118, and heterozygous. All foals with OLWS were homozygous for the Ile118Lys EDNRB mutation, and adults that were homozygous were not found. White patterning was strongly associated with EDNRB genotype. Color patterns with highest incidence (> 94%) of heterozygotes were frame overo, highly white calico overo, and frame blend overo. White-patterned bloodlines with lowest incidence of heterozygotes (< 21 %) were tobiano, sabino, minimally white calico overo, splashed white overo, nonframe blend overo, and breeding-stock solid. The mutation was not detected in solid-colored horses from breeds without white patterning. CONCLUSIONS AND CLINICAL RELEVANCE In homozygotes, the Ile118Lys EDNRB mutation causes OLWS. In heterozygotes, the mutation is usually responsible for a frame overo phenotype. The frame pattern can be combined with other white patterns, making accurate estimation of EDNRB genotype by visual inspection difficult. Wide range of incidence of heterozygotes in various subtypes of white-patterned horses indicates different genetic control of these color patterns. Determination of EDNRB genotype by use of a DNA-based test is the only way to determine with certainty whether white-patterned horses can produce a foal affected with OLWS.
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Affiliation(s)
- E M Santschi
- Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA
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29
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Gariepy CE, Williams SC, Richardson JA, Hammer RE, Yanagisawa M. Transgenic expression of the endothelin-B receptor prevents congenital intestinal aganglionosis in a rat model of Hirschsprung disease. J Clin Invest 1998; 102:1092-101. [PMID: 9739043 PMCID: PMC509092 DOI: 10.1172/jci3702] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The spotting lethal rat, a naturally occurring rodent model of Hirschsprung disease, carries a deletion in the endothelin-B receptor (EDNRB) gene that abrogates expression of functional EDNRB receptors. Rats homozygous for this mutation (sl) exhibit coat color spotting and congenital intestinal aganglionosis. These deficits result from failure of the neural crest-derived epidermal melanoblasts and enteric nervous system (ENS) precursors to completely colonize the skin and intestine, respectively. We demonstrate that during normal rat development, the EDNRB mRNA expression pattern is consistent with expression by ENS precursors throughout gut colonization. We used the human dopamine-beta-hydroxylase (DbetaH) promoter to direct transgenic expression of EDNRB to colonizing ENS precursors in the sl/sl rat. The DbetaH-EDNRB transgene compensates for deficient endogenous EDNRB in these rats and prevents the intestinal defect. The transgene has no effect on coat color spotting, indicating the critical time for EDNRB expression in enteric nervous system development begins after separation of the melanocyte lineage from the ENS lineage and their common precursor. The transgene dosage affects both the incidence and severity of the congenital intestinal defect, suggesting dosage-dependent events downstream of EDNRB activation in ENS development.
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Affiliation(s)
- C E Gariepy
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9050, USA
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30
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Santschi EM, Purdy AK, Valberg SJ, Vrotsos PD, Kaese H, Mickelson JR. Endothelin receptor B polymorphism associated with lethal white foal syndrome in horses. Mamm Genome 1998; 9:306-9. [PMID: 9530628 DOI: 10.1007/s003359900754] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Overo lethal white syndrome (OLWS) is an inherited syndrome of foals born to American Paint Horse parents of the overo coat-pattern lineage. Affected foals are totally or almost totally white and die within days from complications due to intestinal aganglionosis. Related conditions occur in humans and rodents in which mutations in the endothelin receptor B (EDNRB) gene are responsible. EDNRB is known to be involved in the developmental regulation of neural crest cells that become enteric ganglia and melanocytes. In this report we identify a polymorphism in the equine EDNRB gene closely associated with OLWS. This Ile to Lys substitution at codon 118 is located within the first transmembrane domain of this seven-transmembrane domain G-protein-coupled receptor protein. All 22 OLWS-affected foals examined were homozygous for the Lys118 EDNRB allele, while all available parents of affected foals were heterozygous. All but one of the parents also had an overo white body-spot phenotype. Solid-colored control horses of other breeds were homozygous for the Ile118 EDNRB allele. Molecular definition of the basis for OLWS in Paint Horses provides a genetic test for the presence of the Lys118 EDNRB allele and adds to our understanding of the basis for coat color patterns in the horse.
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Affiliation(s)
- E M Santschi
- Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul 55108, USA
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31
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Affiliation(s)
- E Marti
- Institute for Animal Breeding, University of Berne, Switzerland
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32
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Affiliation(s)
- M A Skinner
- Washington University School of Medicine, St. Louis, Missouri, USA
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33
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Gariepy CE, Cass DT, Yanagisawa M. Null mutation of endothelin receptor type B gene in spotting lethal rats causes aganglionic megacolon and white coat color. Proc Natl Acad Sci U S A 1996; 93:867-72. [PMID: 8570650 PMCID: PMC40149 DOI: 10.1073/pnas.93.2.867] [Citation(s) in RCA: 158] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Mutations in the gene encoding the endothelin receptor type B (EDNRB) produce congenital aganglionic megacolon and pigment abnormalities in mice and humans. Here we report a naturally occurring null mutation of the EDNRB gene in spotting lethal (sl) rats, which exhibit aganglionic megacolon associated with white coat color. We found a 301-bp deletion spanning the exon 1-intron 1 junction of the EDNRB gene in sl rats. A restriction fragment length polymorphism caused by this deletion perfectly cosegregates with the sl phenotype. The deletion leads to production of an aberrantly spliced EDNRB mRNA that lacks the coding sequence for the first and second putative transmembrane domains of the G-protein-coupled receptor. Radioligand binding assays revealed undetectable levels of functional EDNRB in tissues from homozygous sl/sl rats. We conclude that EDNRB plays an essential role in the normal development of two neural crest-derived cell lineages, epidermal melanocytes and enteric neurons, in three mammalian species--humans, mice, and rats. The EDNRB-deficient rat may also prove valuable in defining the postnatal physiologic role of this receptor.
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Affiliation(s)
- C E Gariepy
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas 75235-9050, USA
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Bödeker D, Türck O, Lovén E, Wieberneit D, Wegner W. Pathophysiological and functional aspects of the megacolon-syndrome of homozygous spotted rabbits. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE A 1995; 42:549-59. [PMID: 8822192 DOI: 10.1111/j.1439-0442.1995.tb00410.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The Megacolon-Syndrome is a hereditary disease of homozygous spotted rabbits (En En). Investigations have been performed on some special traits related to functional aspects of the gut in comparison to vital heterozygous spotted rabbits (En en). It was found that En En rabbits showed significantly reduced sodium absorption rates across the wall of the cecum. Consequently, the dry matter content of the ingesta was reduced at this location, whereas the content of the ashes was increased. These results indicate that a further important pathogenetic aspect of this hereditary disease is an undue liquification of ingesta in proximal parts of the large intestine. Severe clinical problems, however, resulted from obstipation. This is concluded to be a late complication due to and modified by different stressors of endogenic and exogenic origin. Thus, there are some indications that an early site of spot-gene related effects might be the small intestine. This segment of the bowel was shorter and had an increased dry matter proportion of its wall when compared with heterozygous spotted rabbits. But a decreased proportion of dry matter within the wall of the large intestine was found. The latter could be an effect of the hypothyreotic state of metabolism in En En rabbits.
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Affiliation(s)
- D Bödeker
- Institute of Animal Breeding and Genetics, Hannover School of Veterinary Science, Germany
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35
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Puffenberger EG, Hosoda K, Washington SS, Nakao K, deWit D, Yanagisawa M, Chakravart A. A missense mutation of the endothelin-B receptor gene in multigenic Hirschsprung's disease. Cell 1994; 79:1257-66. [PMID: 8001158 DOI: 10.1016/0092-8674(94)90016-7] [Citation(s) in RCA: 590] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Hirschsprung's disease (HSCR) is characterized by an absence of enteric ganglia in the distal colon and a failure of innervation in the gastrointestinal tract. We recently mapped a recessive susceptibility locus (HSCR2) to human chromosome 13q22, which we now demonstrate to be the endothelin-B receptor gene (EDNRB). We identified in HSCR patients a G-->T missense mutation in EDNRB exon 4 that substitutes the highly conserved Trp-276 residue in the fifth transmembrane helix of the G protein-coupled receptor with a Cys residue (W276C). The mutant W276C receptor exhibited a partial impairment of ligand-induced Ca2+ transient levels in transfected cells. The mutation is dosage sensitive, in that W276C homozygotes and heterozygotes have a 74% and a 21% risk, respectively, of developing HSCR. Genotype analysis of patients in a Mennonite pedigree shows HSCR to be a multigenic disorder.
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Affiliation(s)
- E G Puffenberger
- Department of Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, Ohio 44106-4955
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36
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Hosoda K, Hammer RE, Richardson JA, Baynash AG, Cheung JC, Giaid A, Yanagisawa M. Targeted and natural (piebald-lethal) mutations of endothelin-B receptor gene produce megacolon associated with spotted coat color in mice. Cell 1994; 79:1267-76. [PMID: 8001159 DOI: 10.1016/0092-8674(94)90017-5] [Citation(s) in RCA: 703] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Endothelins act on two subtypes of G protein-coupled receptors, termed endothelin-A and endothelin-B receptors. We report a targeted disruption of the mouse endothelin-B receptor (EDNRB) gene that results in aganglionic megacolon associated with coat color spotting, resembling a hereditary syndrome of mice, humans, and other mammalian species. Piebald-lethal (sl) mice exhibit a recessive phenotype identical to that of the EDNRB knockout mice. In crossbreeding studies, the two mutations show no complementation. Southern blotting revealed a deletion encompassing the entire EDNRB gene in the sl chromosome. A milder allele, piebald (s), which produces coat color spotting only, expresses low levels of structurally intact EDNRB mRNA and protein. These findings indicate an essential role for EDNRB in the development of two neural crest-derived cell lineages, myenteric ganglion neurons and epidermal melanocytes. We postulate that defects in the human EDNRB gene cause a hereditary form of Hirschsprung's disease that has recently been mapped to human chromosome 13, in which EDNRB is located.
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Affiliation(s)
- K Hosoda
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, Dallas 75235-9050
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37
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Kapur RP. Contemporary approaches toward understanding the pathogenesis of Hirschsprung disease. PEDIATRIC PATHOLOGY 1993; 13:83-100. [PMID: 8474955 DOI: 10.3109/15513819309048196] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hirschsprung disease (HD), or congenital aganglionosis coli, is a birth defect with heterogeneous causes. In an effort to understand the molecular and cellular bases for this disorder, researchers have investigated enteric neurodevelopment in normal animals and compared these findings with observations of inbred animal strains that develop aganglionosis coli due to mutations at specific genetic loci. Recent technological advances, including use of retroviral and fluorescent lineage makers, immunohistochemical probes, and transgenic mice, have provided insights into the origins, behavior, and properties of enteric neuroblasts. Experiments with mutant murine embryos indicate that aganglionosis coli results from primary failure of neural crest-derived neuroblasts to colonize the distal colon. In at least one model, impaired colonization by neuroblasts may be secondary to environmental defects restricted to colonic mesenchyme. The discovery that human piebald trait, a hereditary disorder with a high incidence of HD, is caused by mutations in a growth factor receptor highlights the importance of regulatory intercellular interactions between nonneuroblastic mesenchyme and neuroblasts during normal development of the enteric nervous system. These observations, coupled with advances in molecular genetics, set the stage for dramatic progress in this field of research in the near future.
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Affiliation(s)
- R P Kapur
- Department of Laboratories, Children's Hospital and Medical Center, Seattle, Washington
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