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Bell SM, Evans JM, Greif EA, Tsai KL, Friedenberg SG, Clark LA. GWAS using low-pass whole genome sequence reveals a novel locus in canine congenital idiopathic megaesophagus. Mamm Genome 2023; 34:464-472. [PMID: 37041421 PMCID: PMC10600401 DOI: 10.1007/s00335-023-09991-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 03/29/2023] [Indexed: 04/13/2023]
Abstract
Congenital idiopathic megaesophagus (CIM) is a gastrointestinal disorder of dogs wherein the esophagus is dilated and swallowing activity is reduced, causing regurgitation of ingesta. Affected individuals experience weight loss and malnourishment and are at risk for aspiration pneumonia, intussusception, and euthanasia. Great Danes have among the highest incidences of CIM across dog breeds, suggesting a genetic predisposition. We generated low-pass sequencing data for 83 Great Danes and used variant calls to impute missing whole genome single-nucleotide variants (SNVs) for each individual based on haplotypes phased from 624 high-coverage dog genomes, including 21 Great Danes. We validated the utility of our imputed data set for genome-wide association studies (GWASs) by mapping loci known to underlie coat phenotypes with simple and complex inheritance patterns. We conducted a GWAS for CIM with 2,010,300 SNVs, identifying a novel locus on canine chromosome 1 (P-val = 2.76 × 10-10). Associated SNVs are intergenic or intronic and are found in two clusters across a 1.7-Mb region. Inspection of coding regions in high-coverage genomes from affected Great Danes did not reveal candidate causal variants, suggesting that regulatory variants underlie CIM. Further studies are necessary to assess the role of these non-coding variants.
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Affiliation(s)
- Sarah M Bell
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Jacquelyn M Evans
- College of Veterinary Medicine, Baker Institute for Animal Health, Cornell University, Ithaca, NY, USA
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Elizabeth A Greif
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Kate L Tsai
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Steven G Friedenberg
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA.
| | - Leigh Anne Clark
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.
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Koeppel K, O'Dell J, Stevenage C, van der Zee H, Schoeman JP. Successful management of gastroesophageal intussusception in an adult puma (
Puma concolor). VETERINARY RECORD CASE REPORTS 2022. [DOI: 10.1002/vrc2.453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Katja Koeppel
- Department of Production Animal Studies and Centre for Veterinary Wildlife Studies Faculty of Veterinary Science University of Pretoria Onderstepoort South Africa
| | - Jacques O'Dell
- Department of Production Animal Studies and Centre for Veterinary Wildlife Studies Faculty of Veterinary Science University of Pretoria Onderstepoort South Africa
| | - Craig Stevenage
- Department of Companion Animal Clinical Studies Faculty of Veterinary Science University of Pretoria Onderstepoort South Africa
| | - Hans van der Zee
- Department of Companion Animal Clinical Studies Faculty of Veterinary Science University of Pretoria Onderstepoort South Africa
| | - Johan P. Schoeman
- Department of Companion Animal Clinical Studies Faculty of Veterinary Science University of Pretoria Onderstepoort South Africa
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Bell SM, Evans JM, Evans KM, Tsai KL, Noorai RE, Famula TR, Holle DM, Clark LA. Congenital idiopathic megaesophagus in the German shepherd dog is a sex-differentiated trait and is associated with an intronic variable number tandem repeat in Melanin-Concentrating Hormone Receptor 2. PLoS Genet 2022; 18:e1010044. [PMID: 35271580 PMCID: PMC8912139 DOI: 10.1371/journal.pgen.1010044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 01/20/2022] [Indexed: 11/19/2022] Open
Abstract
Congenital idiopathic megaesophagus (CIM) is a gastrointestinal (GI) motility disorder of dogs in which reduced peristaltic activity and dilation of the esophagus prevent the normal transport of food into the stomach. Affected puppies regurgitate meals and water, fail to thrive, and experience complications such as aspiration pneumonia that may necessitate euthanasia. The German shepherd dog (GSD) has the highest disease incidence, indicative of a genetic predisposition. Here, we discover that male GSDs are twice as likely to be affected as females and show that the sex bias is independent of body size. We propose that female endogenous factors (e.g., estrogen) are protective via their role in promoting relaxation of the sphincter between the esophagus and stomach, facilitating food passage. A genome-wide association study for CIM revealed an association on canine chromosome 12 (P-val = 3.12x10-13), with the lead SNPs located upstream or within Melanin-Concentrating Hormone Receptor 2 (MCHR2), a compelling positional candidate gene having a role in appetite, weight, and GI motility. Within the first intron of MCHR2, we identified a 33 bp variable number tandem repeat (VNTR) containing a consensus binding sequence for the T-box family of transcription factors. Across dogs and wolves, the major allele includes two copies of the repeat, whereas the predominant alleles in GSDs have one or three copies. The single-copy allele is strongly associated with CIM (P-val = 1.32x10-17), with homozygosity for this allele posing the most significant risk. Our findings suggest that the number of T-box protein binding motifs may correlate with MCHR2 expression and that an imbalance of melanin-concentrating hormone plays a role in CIM. We describe herein the first genetic factors identified in CIM: sex and a major locus on chromosome 12, which together predict disease state in the GSD with greater than 75% accuracy. German shepherd dogs (GSDs) are predisposed to an inherited motility disorder of the esophagus, termed congenital idiopathic megaesophagus (CIM), in which swallowing is ineffective and the esophagus is enlarged. Affected puppies are unable to properly pass food into their stomachs and consequently regurgitate their meals and show a failure to thrive, often leading to euthanasia. Here, we discovered that male GSDs are affected at a ratio of almost 2-to-1 over females, suggesting a protective biological advantage in females. In humans, estrogen is thought to play a role in the male predominance of esophageal disorders like reflux esophagitis and esophageal cancer. In a genome-wide scan, we identified an association with CIM on chromosome 12 and, within this region, a repetitive sequence in MCHR2. This gene encodes a receptor for melanin-concentrating hormone, a signaling molecule that is linked to appetite, weight, and gut motility. Together, sex and the MCHR2 repeat sequence accurately predict affection status in over 75% of dogs, and a genetic test is now available to facilitate breeding decisions aimed at reducing disease incidence.
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Affiliation(s)
- Sarah M. Bell
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Jacquelyn M. Evans
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Katy M. Evans
- The Seeing Eye Inc., Morristown, New Jersey, United States of America
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, United Kingdom
| | - Kate L. Tsai
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Rooksana E. Noorai
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
- Clemson University Genomics and Bioinformatics Facility, Clemson University, Clemson, South Carolina, United States of America
| | - Thomas R. Famula
- Department of Animal Science, University of California, Davis, California, United States of America
| | - Dolores M. Holle
- The Seeing Eye Inc., Morristown, New Jersey, United States of America
| | - Leigh Anne Clark
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
- * E-mail:
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Brincin C, Ryan T, Harris K. Gastroesophageal intussusception secondary to induction of emesis with subsequent development of septic pericardial effusion after corrective surgery. J Small Anim Pract 2021; 63:72-77. [PMID: 34370318 DOI: 10.1111/jsap.13395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 05/22/2021] [Accepted: 06/03/2021] [Indexed: 11/28/2022]
Abstract
A juvenile boxer dog was diagnosed with gastroesophageal intussusception that occurred after the induction of emesis with apomorphine. A ventral midline coeliotomy and diaphragmotomy were performed and the intussusception was manually reduced. Despite initial satisfactory recovery, the dog was diagnosed with cardiac tamponade 1 week post-operatively. Escherichia coli was cultured from pericardial and pleural effusion samples. During subtotal pericardiectomy surgery the pericardium was found to be markedly thickened with adhesions to the epicardium, thoracic wall and diaphragm. Substantial haemorrhage and refractory hypotension necessitated the administration of a blood transfusion during surgery. The dog entered cardiac arrest in the immediate post-operative period and cardiopulmonary resuscitation was unfortunately unsuccessful. Gastroesophageal intussusception should be considered a possible severe adverse effect of administering apomorhine to induce emesis in dogs. Additionally, septic pericardial and pleural effusions may occur post-reduction of gastroesophageal intussusception.
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Affiliation(s)
- C Brincin
- Southern Counties Veterinary Specialists, Unit 6 Forest Corner Farm, Hangerlsey, Ringwood, BH24 3JW, UK
| | - T Ryan
- Highcroft Veterinary Referrals, 615 Wells Rd, Bristol, BS14 9BE, UK
| | - K Harris
- Southern Counties Veterinary Specialists, Unit 6 Forest Corner Farm, Hangerlsey, Ringwood, BH24 3JW, UK
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Rohwedder T, Hellmuth VC. Gastroesophageal intussusception with complete herniation of the spleen in a 12 months old dog with idiopathic megaoesophagus. VETERINARY RECORD CASE REPORTS 2021. [DOI: 10.1002/vrc2.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Tayler S, Mullowney D, Lataretu A, Plested M, Tuan J, Kathrani A. Gastroesophageal intussusception and extreme esophageal dilatation secondary to bilateral laryngeal paralysis in a cat. J Vet Intern Med 2021; 35:1088-1092. [PMID: 33559171 PMCID: PMC7995417 DOI: 10.1111/jvim.16056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 12/13/2022] Open
Abstract
Gastroesophageal intussusception, extreme esophageal dilatation, and laryngeal paralysis are individually rare clinical entities in cats and the simultaneous occurrence in a single animal has not been described. We describe these 3 conditions occurring concurrently in a geriatric cat, and resolution of the cat's clinical signs after treatment with unilateral arytenoid lateralization. This finding supports the need for thorough history taking and examination in cats with extreme esophageal dilatation to determine if upper respiratory tract abnormalities are present, as appropriate treatment might resolve the esophageal dilatation.
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Affiliation(s)
- Sarah Tayler
- Department of Clinical Science and Services, Royal Veterinary College, Hertfordshire, United Kingdom
| | - Deirdre Mullowney
- Department of Clinical Science and Services, Royal Veterinary College, Hertfordshire, United Kingdom
| | | | - Mark Plested
- Department of Clinical Science and Services, Royal Veterinary College, Hertfordshire, United Kingdom
| | - Jayson Tuan
- Department of Clinical Science and Services, Royal Veterinary College, Hertfordshire, United Kingdom
| | - Aarti Kathrani
- Department of Clinical Science and Services, Royal Veterinary College, Hertfordshire, United Kingdom
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