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A form of dystrophinopathy with mild or subclinical neuromuscular signs has been previously reported in a family of Labrador retrievers. Markedly and persistently elevated creatine kinase activity was first noted at 6 months of age. Skeletal muscle biopsies revealed a dystrophic phenotype, with dystrophin non-detectable on western blotting and immunohistochemical staining, and with increased utrophin expression. In this report we demonstrate with western blotting that α-dystroglycan is present at essentially normal levels. Whole genome sequencing has also now revealed an approximately 400kb tandem genomic DNA duplication including exons 2-7 of the DMD gene that was inserted into intron 7 of the wild type gene. Skeletal muscle cDNA from 2 cases contained DMD transcripts as expected from an in-frame properly-spliced exon 2-7 tandem insertion. A similar 5' duplication involving DMD exons 2-7 has been reported in a human family with dilated cardiomyopathy but without skeletal myopathy. This is the 3rd confirmed mutation in the DMD gene in Labrador retrievers.

A 2‐year‐old female spayed dog was presented with a chronic history of short‐strided gait and inability to completely open the jaw. Clinical signs were present since the dog was adopted from a humane society at a few months of age. Serum creatine kinase activity was abnormally high. Neurological examination, electromyography, muscle biopsies with immunofluorescent staining, and whole genome sequencing (WGS) were performed. A dystrophic phenotype was identified histologically in muscle biopsies, deficiency of laminin α2 protein was confirmed by immunofluorescent staining, and a deletion in the LAMA2 gene was identified by analysis of the WGS data. Congenital muscular dystrophy associated with a disease variant in LAMA2 was identified.

Alpha-dystroglycan (αDG) is a highly glycosylated cell surface protein with a significant role in cell-to-extracellular matrix interactions in muscle. αDG interaction with extracellular ligands relies on the activity of the LARGE1 glycosyltransferase that synthesizes and extends the heteropolysaccharide matriglycan. Abnormalities in αDG glycosylation and formation of matriglycan are the pathogenic mechanisms for the dystroglycanopathies, a group of congenital muscular dystrophies. Muscle biopsies were evaluated from related 6-week-old Labrador retriever puppies with poor suckling, small stature compared to normal litter mates, bow-legged stance and markedly elevated creatine kinase activities. A dystrophic phenotype with marked degeneration and regeneration, multifocal mononuclear cell infiltration and endomysial fibrosis was identified on muscle cryosections. Single nucleotide polymorphism (SNP) array genotyping data on the family members identified three regions of homozygosity in 4 cases relative to 8 controls. Analysis of whole genome sequence data from one of the cases identified a stop codon mutation in the LARGE1 gene that truncates 40% of the protein. Immunofluorescent staining and western blotting demonstrated the absence of matriglycan in skeletal muscle and heart from affected dogs. Compared to control, LARGE enzyme activity was not detected. This is the first report of a dystroglycanopathy in dogs.

Profiling the adaptive immune repertoire using next generation sequencing (NGS) has become common in human medicine, showing promise in characterizing clonal expansion of B cell clones through analysis of B cell receptors (BCRs) in patients with lymphoid malignancies. In contrast, most work evaluating BCR repertoires in dogs has employed traditional PCR-based approaches analyzing the IGH locus only. The objectives of this study were to: (1) describe a novel NGS protocol to evaluate canine BCRs; (2) develop a bioinformatics pipeline for processing canine BCR sequencing data; and (3) apply these methods to derive insights into BCR repertoires of healthy dogs and dogs undergoing treatment for B-cell lymphoma. RNA from peripheral blood mononuclear cells of healthy dogs (n = 25) and dogs newly diagnosed with intermediate-to-large B-cell lymphoma (n = 18) with intent to pursue chemotherapy was isolated, converted into cDNA and sequenced by NGS. The BCR repertoires were identified and quantified using a novel analysis pipeline. The IGK repertoires of the healthy dogs were far less diverse compared to IGL which, as with IGH, was highly diverse. Strong biases at key positions within the CDR3 sequence were identified within the healthy dog BCR repertoire. For a subset of the dogs with B-cell lymphoma, clonal expansion of specific IGH sequences pre-treatment and reduction post-treatment was observed. The degree of expansion and reduction correlated with the clinical outcome in this subset. Future studies employing these techniques may improve disease monitoring, provide earlier recognition of disease progression, and ultimately lead to more targeted therapeutics.

OBJECTIVE: To determine whether red blood cell distribution width (RDW) is associated with an increased odds of mortality in hospitalized dogs and cats. DESIGN: Retrospective, single-center study; data collected from 2007 to 2017. SETTING: University teaching hospital. ANIMALS: Six thousand six hundred and sixty-one animals (5,183 dogs and 1,478 cats). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were identified from animals presented to the emergency service and admitted to the ICU with a CBC and serum biochemistry performed on admission. Patients were stratified into quintiles based upon presenting RDW, and logistic regression modeling was performed to evaluate the relationship between RDW and in-hospital mortality. Canine patients with a presenting RDW in the upper fourth and fifth quintiles had an increased odds of all-cause in-hospital mortality (P < 0.0001). Specifically, dogs in the upper fifth quintile had a 2.1-fold greater odds of death compared to dogs in the first quintile, and dogs in the upper fourth quintile had a 1.9-fold greater odds of death compared to dogs in the first quintile. This relationship remained significant after adjusting for age, sex, key laboratory values excluding HCT, medical vs surgical disease, and diagnosis category. This relationship was no longer significant with the inclusion of HCT. No significant association was identified between presenting RDW and in-hospital mortality in cats. CONCLUSIONS: Hospitalized dogs with higher RDW on presentation to the emergency service have greater odds of all-cause in-hospital mortality compared to dogs with a lower RDW. A similar association between RDW and mortality was not found in cats. Further studies are warranted to assess the usefulness of this biomarker for specific diseases in dogs and to better understand the mechanisms driving the association between increased RDW and mortality in canine patients.

Familial mitral valve prolapse in human beings has been associated with several genetic variants; however, in most cases, a known variant has not been identified. Dogs also have a naturally occurring form of familial mitral valve disease (MMVD) with similarities to the human disease. A shared genetic background and clinical phenotype of this disease in some dog breeds has indicated that the disease may share a common genetic cause. We evaluated DNA from 50 affected dogs from five different dog breeds in a whole genome sequencing approach to identify shared variants across and within breeds that could be associated with MMVD. No single causative genetic mutation was found from the 50 dogs with MMVD. Ten variants were identified in 37/50 dogs around and within the MED13L gene. These variants were no longer associated with MMVD when evaluated with a larger cohort including both affected and unaffected dogs. No high/moderate impact variants were identified in 10/10 miniature poodles, one was identified in 10/10 Yorkshire Terriers and 10/10 dachshunds, respectively, 14 were identified in 10/10 Miniature schnauzers, and 19 in 10/10 CKCS. Only one of these could be associated with the cardiac valve (Chr12:36801705, COL12A1; CKCS) but when evaluated in an additional 100 affected CKCS the variant was only identified in 84/100 affected dogs, perhaps indicating genetic heterogeneity in this disease. Our findings indicate that development of MMVD in the dog may be related to a combination of genetic and environmental factors that impact specific molecular pathways rather than a single shared genetic variant across or within breeds.

In this report, we describe a novel genetic basis for congenital dyserythropoietic anemia and polymyopathy in Labrador Retriever littermates characterized by incidental detection of marked microcytosis, inappropriate metarubricytosis, pelvic limb weakness and muscle atrophy. A similar syndrome has been described in English Springer Spaniel littermates with an early onset of anemia, megaesophagus, generalized muscle atrophy and cardiomyopathy. Muscle histopathology in both breeds showed distinctive pathological changes consistent with congenital polymyopathy. Using whole genome sequencing and mapping to the CanFam4 (Canis lupus familiaris reference assembly 4), a nonsense variant in the EHBP1L1 gene was identified in a homozygous form in the Labrador Retriever littermates. The mutation produces a premature stop codon that deletes approximately 90% of the protein. This variant was not present in the English Springer Spaniels. Currently, EHPB1L1 is described as critical to actin cytoskeletal organization and apical-directed transport in polarized epithelial cells, and through connections with Rab8 and a BIN1-dynamin complex generates membrane vesicles in the endocytic recycling compartment. Furthermore, EHBP1L1 knockout mice die early and develop severe anemia. The connection of EHBP1L1 to BIN1 and DMN2 functions is particularly interesting due to BIN1 and DMN2 mutations being causative in forms of centronuclear myopathy. This report, along with an independent study conducted by another group, are the first reports of an association of EHBP1L1 mutations with congenital dyserythropoietic anemia and polymyopathy.

Pigment production and distribution is controlled through multiple genes, resulting in a wide range of coat color phenotypes in dogs. Dogs that produce only the pheomelanin pigment vary in intensity from white to deep red. The Poodle breed has a wide range of officially recognized coat colors, including the pheomelanin-based white, cream, apricot, and red coat colors, which are not fully explained by the previously identified genetic variants involved in pigment intensity. Here, a genome-wide association study for pheomelanin intensity was performed in Poodles which identified an association on canine chromosome 18. Whole-genome sequencing data revealed an SNN retrocopy insertion (SNNL1) in apricot and red Poodles within the associated region on chromosome 18. While equal numbers of melanocytes were observed in all Poodle skin hair bulbs, higher melanin content was observed in the darker Poodles. Several genes involved in melanogenesis were also identified as highly overexpressed in red Poodle skin. The most differentially expressed gene however was GPR22, which was highly expressed in red Poodle skin while unexpressed in white Poodle skin (log2 fold change in expression 6.1, P

In this report, we describe a novel genetic basis for congenital dyserythropoietic anemia and polymyopathy in Labrador Retriever littermates characterized by incidental detection of marked microcytosis, inappropriate metarubricytosis, pelvic limb weakness and muscle atrophy. A similar syndrome has been described in English Springer Spaniel littermates with an early onset of anemia, megaesophagus, generalized muscle atrophy and cardiomyopathy. Muscle histopathology in both breeds showed distinctive pathological changes consistent with congenital polymyopathy. Using whole genome sequencing and mapping to the CanFam4 (

Autoantibody biomarkers are valuable tools used to diagnose and manage autoimmune diseases in dogs. However, prior publications have raised concerns over a lack of standardization and sufficient validation for the use of biomarkers in veterinary medicine.Systematically compile primary research on autoantibody biomarkers for autoimmune disease in dogs, summarize their methodological features, and evaluate their quality; synthesize data supporting their use into a resource for veterinarians and researchers.Not used.Five indices were searched to identify studies for evaluation: PubMed, CAB Abstracts, Web of Science, Agricola, and SCOPUS. Two independent reviewers (AET and ELC) screened titles and abstracts for exclusion criteria followed by full-text review of remaining articles. Relevant studies were classified based on study objectives (biomarker, epitope, technique). Data on study characteristics and outcomes were synthesized in independent data tables for each classification.Ninety-two studies qualified for final analysis (n = 49 biomarker, n = 9 epitope, and n = 34 technique studies). A high degree of heterogeneity in study characteristics and outcomes reporting was observed. Opportunities to strengthen future studies could include: (1) routine use of negative controls, (2) power analyses to inform sample sizes, (3) statistical analyses when appropriate, and (4) multiple detection techniques to confirm results.These findings provide a resource that will allow veterinary clinicians to efficiently evaluate the evidence supporting the use of autoantibody biomarkers, along with the varied methodological approaches used in their development.

Dogs represent a unique spontaneous cancer model. Osteosarcoma (OSA) is the most common primary bone tumor in dogs (OMIA 001441-9615), and strongly resembles human forms of OSA. Several large- to giant-sized dog breeds, including the Leonberger, have a greatly increased risk of developing OSA. We performed genome-wide association analysis with high-density imputed SNP genotype data from 273 Leonberger cases with a median age of 8.1 [3.1–13.5] years and 365 controls older than eight years. This analysis revealed significant associations at the CDKN2A/B gene locus on canine chromosome 11, mirroring previous findings in other dog breeds, such as the greyhound, that also show an elevated risk for OSA. Heritability (h2SNP) was determined to be 20.6% (SE = 0.08; p-value = 5.7 × 10−4) based on a breed prevalence of 20%. The 2563 SNPs across the genome accounted for nearly all the h2SNP of OSA, with 2183 SNPs of small effect, 316 SNPs of moderate effect, and 64 SNPs of large effect. As with many other cancers it is likely that regulatory, non-coding variants underlie the increased risk for cancer development. Our findings confirm a complex genetic basis of OSA, moderate heritability, and the crucial role of the CDKN2A/B locus leading to strong cancer predisposition in dogs. It will ultimately be interesting to study and compare the known genetic loci associated with canine OSA in human OSA.

Myelofibrosis often lacks an identifiable cause in dogs. In humans, most primary myelofibrosis cases develop secondary to driver mutations in JAK2, CALR, or MPL.To determine the prevalence of variants in JAK2, CALR, or MPL candidate regions in dogs with myelofibrosis and in healthy dogs.Twenty-six dogs with myelofibrosis that underwent bone marrow biopsy between 2010 and 2018 and 25 control dogs matched for age, sex, and breed.Cross-sectional study. Amplicon sequencing of JAK2 exons 12 and 14, CALR exon 9, and MPL exon 10 was performed on formalin-fixed, decalcified, paraffin-embedded bone marrow (myelofibrosis) or peripheral blood (control) DNA. Somatic variants were categorized as likely-benign or possibly-pathogenic based on predicted impact on protein function. Within the myelofibrosis group, hematologic variables and survival were compared by variant status (none, likely-benign only, and ≥1 possibly-pathogenic). The effect of age on variant count was analyzed using linear regression.Eighteen of 26 (69%) myelofibrosis cases had somatic variants, including 9 classified as possibly-pathogenic. No somatic variants were detected in controls. Within the myelofibrosis group, hematologic variables and survival did not differ by variant status. The number of somatic variants per myelofibrosis case increased with age (estimate, 0.69; SE, 0.29; P = .03).Somatic variants might initiate or perpetuate myelofibrosis in dogs. Our findings suggest the occurrence of clonal hematopoiesis in dogs, with increasing incidence with age, as observed in humans.

Funder: Italian Spinone Club of Great Britain, Funder: Kennel Club Charitable Trust, Genotype imputation using a reference panel that combines high-density array data and publicly available whole genome sequence consortium variant data is potentially a cost-effective method to increase the density of extant lower-density array datasets. In this study, three datasets (two Border Collie; one Italian Spinone) generated using a legacy array (Illumina CanineHD, 173 662 SNPs) were utilised to assess the feasibility and accuracy of this approach and to gather additional evidence for the efficacy of canine genotype imputation. The cosmopolitan reference panels used to impute genotypes comprised dogs of 158 breeds, mixed breed dogs, wolves and Chinese indigenous dogs, as well as breed-specific individuals genotyped using the Axiom Canine HD array. The two Border Collie reference panels comprised 808 individuals including 79 Border Collies and 426 326 or 426 332 SNPs; and the Italian Spinone reference panel comprised 807 individuals including 38 Italian Spinoni and 476 313 SNPs. A high accuracy for imputation was observed, with the lowest accuracy observed for one of the Border Collie datasets (mean R2 = 0.94) and the highest for the Italian Spinone dataset (mean R2 = 0.97). This study's findings demonstrate that imputation of a legacy array study set using a reference panel comprising both breed-specific array data and multi-breed variant data derived from whole genomes is effective and accurate. The process of canine genotype imputation, using the valuable growing resource of publicly available canine genome variant datasets alongside breed-specific data, is described in detail to facilitate and encourage use of this technique in canine genetics.

Causative mutations for familial dilated cardiomyopathy (DCM) have been identified in the phospholamban gene. There are many poorly understood aspects about familial DCM (variable penetrance, expression) which may be studied in natural animal models. We characterized genetic aspects of familial DCM in a canine model with a high incidence of sudden death. A missense G > A mutation in exon 1 of the phospholamban gene that changed an amino acid from arginine to histidine was identified in affected dogs. This variant was predicted to be deleterious. We describe a spontaneous canine model of familial DCM and sudden death with the R9H mutation. In comparison to a reported human family, the variant was highly penetrant and resulted in sudden death. Genetic penetrance of this mutation may be influenced by genetic or environmental modifiers. The dog provides an excellent model in which to study complex aspects of familial DCM.

Addison’s disease (AD) is a life-threatening endocrine disorder that occurs spontaneously in both humans and dogs. Associations between MHC class II genes and AD have been shown in several human studies. Our goal was to identify MHC class II associations with AD in a large population of Standard Poodles, a breed highly predisposed to AD. We sequenced exon 2 of the class II genes DLA-DRB1, DLA-DQA1, and DLA-DQB1 in 110 affected and 101 unaffected Standard Poodles and tested for association with AD. After correcting for population structure, two haplotypes were found to confer risk of developing AD in a sex-specific manner: DLA-DRB1*015:01-DQA1*006:01-DQB1*023:01 in males (x2p = 0.03, OR 2.1) and DLA-DRB1*009:01-DQA1*001:01-DQB1*008:01:1 in females (x2p = 0.02, OR 8.43). Sex-specific associations have been previously described in human populations, but this is the first report of this kind in dogs. Consistent with findings in other studies, we found the DLA-DQA1*006:01 allele (x2p = 0.04) to be associated with AD in males independent of haplotype. In females, the haplotype DLA-DRB1*009:01-DQA1*001:01-DQB1*008:01:1 confers a very high risk for developing AD, although its frequency was rare (9 of 124 females) in our study population. Further studies are warranted to validate the findings of this exploratory dataset and to assess the usefulness of this haplotype as a risk marker for AD in female Standard Poodles. Our results highlight the importance of evaluating MHC class II disease associations in large populations, and accounting for both biological sex and population structure.

Background Atopic dermatitis (AD) is a common disease of dogs and humans. In both species, the interplay of genetic and environmental factors affect disease expression. In dogs with AD, differences in the breed studied and in their geographical origin have led to heterogeneity in genetic association and while different loci have been identified, a causative genetic mutation has not. We hypothesized that AD could be mapped in a large cohort of rigorously phenotyped, geographically restricted West Highland White Terriers (WHWT), a breed with a high prevalence of the disease. Objectives A) Collect phenotypes and DNA from a large cohort of WHWT born in the USA. B) Perform a genome-wide association study (GWAS) for AD in these dogs to identify associated regions and genes of interest. C) Sequence genes of interest to identify pathologic variants. Methods We collected DNA from 96 WHWT with AD and 87 controls from the same breed. DNA was isolated and dogs were genotyped using the Illumina CanineHD BeadChip. A GWAS was performed using EMMAX and associated regions were examined for genes of interest. Genes with possible relevance to AD were examined more closely in two affected and two normal WHWT using next-generation sequencing. Variants in these genes that were unique to the two affected WHWT were compared to a database of variants derived from whole genome sequencing of 200 non-WHWT dogs across 33 additional breeds. Results The GWAS identified a 2.7 Mb genomic region on CFA3 that included 37 genes. There was a missense variant in the F2R gene in both affected dogs but this variant was also found in 35 dogs in 9 breeds in the database of whole genome sequences for whom the phenotype regarding atopic dermatitis was unknown. Conclusions Atopic dermatitis in WHWT is associated with a region on CFA3 that contains several candidate genes. Of these, a homozygous variant in the F2R gene present in multiple breeds that also suffer from AD warrants further evaluation.

Background Genetic heterogeneity of the canine angiotensin converting enzyme (ACE) gene is functionally important because the degree of aldosterone breakthrough with ACE-inhibitor therapy is greater in variant positive dogs compared to variant negative dogs, but the prevalence of the variant is not known. The purpose of this study was to determine ACE gene variant-positive prevalence in a population of 497 dogs of different breeds. Results Overall variant-positive prevalence was 31%, with 20% of dogs heterozygous and 11% of dogs homozygous. The variant was overrepresented in Irish Wolfhounds (prevalence 95%; P, Plain English summary Genetic differences in the angiotensin converting enzyme (ACE) have been shown to affect the way dogs respond to ACE-inhibitors, a class of medication which is used to treat dogs with heart disease. Dogs that have a genetic mutation of the ACE gene show less benefit with ACE-inhibitor medications than dogs without the mutation, but it is not known how common the mutation is in dogs. The purpose of this study was to determine the prevalence of this mutation (variant) in a large population of dogs of different breeds. The overall variant-positive prevalence in this population of 497 dogs was 31%. The variant was overrepresented in Irish Wolfhounds (prevalence 95%), Dachshunds (prevalence 90%), Cavalier King Charles Spaniels (prevalence 85%), Great Danes (prevalence 84%), and Bull Mastiffs (prevalence 58%). Irish Wolfhounds were more likely than other breeds to have 2 copies of the mutation (homozygous) than 1 copy of the mutation (heterozygous). The clinical importance of high ACE gene variant-positive prevalence in some breeds will require additional studies because some breeds are predisposed to heart disease, for which treatment with ACE-inhibitor medication might be recommended.

Junctional epidermolysis bullosa (JEB) is a group of congenital blistering skin diseases characterized by clefting through the lamina lucida of the basement membrane zone.To characterize the clinical and morphological features of a congenital mechanobullous disease in a litter of puppies with severe upper respiratory involvement, and to identify an associated genetic variant.Five of eight puppies in an Australian cattle dog cross-bred litter showed signs of skin fragility. Three were stillborn and one died at one month of age. The two surviving puppies were presented with blistering skin disease and severe respiratory distress. Additionally, one unaffected sibling was examined and blood was obtained for genetic testing.Post-mortem examination, histopathological evaluation and electron microscopy were performed. Whole genome sequencing (WGS) of one affected puppy was compared to a database of 522 dogs of 55 different breeds for variant analysis. Sanger sequencing of one additional affected and one unaffected sibling confirmed the variant.Clinically, severe mucocutaneous ulcers occurred in frictional areas with claw sloughing. Histopathological results revealed subepidermal clefts and electron microscopy confirmed the split in the lamina lucida. Post-mortem examination documented extensive pharyngeal and laryngeal lesions with granulation tissue and fibrinous exudate obscuring the airway. Moderate tracheal hypoplasia contributed. The WGS revealed a novel missense variant in the laminin α3-chain XP_537297.2p(Asp2867Val), with an autosomal recessive mode of inheritance.A novel variant in LAMA3 caused a generalized and severe phenotype of JEB with an unique clinical presentation of upper airway obstruction.L’épidermolyse bulleuse jonctionnelle (JEB) est un groupe de dermatoses cutanées congénitales vésiculeuses caractérisées par un clivage au niveau de la lamina lucida de la membrane basale.Caractériser les critères cliniques et morphologiques de maladies bulleuses congénitales dans une portée de chiots avec troubles respiratoires sévères et identifier un variant génétique associé.Cinq des huit chiots d’une portée de chiens croisés bouvier australien ont montré des signes de fragilité cutanée. Trois étaient mort-nés et un est mort à l’âge d’un mois. Les deux chiots survivants ont été présentés avec une dermatose vésiculeuse et des troubles respiratoires sévères. En outre, un chiot sain a été examiné et du sang a été prélevé pour tests génétiques. MATÉRIELS ET MÉTHODES: Un examen post-mortem, une évaluation histopathologique et electro-microscopique ont été réalisés. Le séquençage complet du génome (WGS) d’un chiot atteint a été comparé à une base de données de 522 chiens de 55 races différentes pour une analyse de variant. Le séquençage de Sanger d’un autre chiot atteint et un chiot sain a confirmé le variant. RÉSULTATS: Cliniquement, les ulcères cutanéo-muqueux sévères étaient observés aux zones de friction avec pertes des griffes. Les résultats histopathologiques révélèrent des séparations sous épidermiques et l’électro-microscopie a confirmé le clivage au sein de la lamina lucida. L’examen post mortem a documenté des lésions laryngées et pharyngées extensives avec tissue de granulation et exsudat fibrineux dissimulant les voies aériennes. Une hypoplasie trachéale modérée y contribuait. Le WGS a révélé un nouveau variant contre-sens dans la chaine α3 de laminine XP_537297.2p(Asp2867Val), avec un mode autosomal récessif de transmission.Un nouveau variant cause un phénotype de JEB sévère et généralisé avec une présentation clinique unique d’obstruction des voies respiratoires supérieures.INTRODUCCIÓN: la epidermólisis bullosa de la unión (JEB) es un grupo de enfermedades cutáneas congénitas con formación de ampollas caracterizadas por una hendidura a lo largo de la lámina lúcida de la zona de la membrana basal. OBJETIVOS: establecer las características clínicas y morfológicas de una enfermedad mecanobullosa congénita en una camada de cachorros con afectación respiratoria superior grave e identificar una variante genética asociada. ANIMALES: cinco de los ocho cachorros en una camada mestiza de perros de ganado australiano mostraron signos de fragilidad de la piel. Tres nacieron muertos y uno murió al mes de edad. Los dos cachorros supervivientes presentaron una enfermedad cutánea con ampollas y dificultad respiratoria grave. Además, se examinó a un hermano no afectado y se extrajo sangre para realizar pruebas genéticas. MÉTODOS Y MATERIALES: Se realizó examen post-mortem, evaluación histopatológica y microscopía electrónica. La secuenciación del genoma completo (WGS) de un cachorro afectado se comparó con una base de datos de 522 perros de 55 razas diferentes para el análisis de variantes. La secuenciación de Sanger de un hermano afectado adicional y un hermano no afectado confirmó la variante. RESULTADOS: Clínicamente, se produjeron úlceras mucocutáneas graves en áreas de fricción con desprendimiento de garras. Los resultados histopatológicos revelaron hendiduras subepidérmicas y la microscopía electrónica confirmó la escisión en la lámina lúcida. El examen post-mortem documentó extensas lesiones faríngeas y laríngeas con tejido de granulación y exudado fibrinoso que oscurecía las vías respiratorias. A las lesions también se añadía una hipoplasia traqueal moderada. El WGS reveló una nueva variante sin sentido en la cadena α3 de laminina XP_537297.2p (Asp2867Val), con un modo de herencia autosómico recesivo. CONCLUSIÓN Y RELEVANCIA CLÍNICA: una nueva variante genética causó un fenotipo generalizado y severo de JEB con una presentación clínica única de obstrucción de las vías respiratorias superiores.Die Junctional Epidermolysis Bullosa (JEB) umfasst eine Gruppe kongenitaler blasenbildender Hauterkrankungen, die durch eine Spaltbildung durch die Lamina lucida der Basalmembranzone charakterisiert sind. ZIEL: Die Charakterisierung klinischer und morphologischer Merkmale einer kongenitalen mechanobullösen Erkrankung bei einem Wurf von Welpen mit hochgradiger respiratorischer Beteiligung sowie eine Identifizierung der damit zusammenhängenden genetischen Variante.Fünf von acht Welpen eines Australian cattle Dog Mischlingswurfes zeigten Zeichen von Hautfragilität. Drei waren totgeboren und ein Welpe starb mit einem Monat. Die zwei überlebenden Welpen wurden mit einer blasenbildenden Hauterkrankung und hochgradiger respiratorischer Not vorgestellt. Zusätzlich wurde ein nicht betroffenes Geschwister untersucht und Blut zur genetischen Analyse genommen.Eine Post Mortem Untersuchung, eine histopathologische Evaluierung und Elektronenmikroskopie wurden durchgeführt. Eine Ganz-Genom Sequenzierung (WGS) eines erkrankten Welpen wurde mit der Datenbank von 522 Hunden 55 verschiedener Rassen zur Varianzanalyse verglichen. Mittels Sanger Sequenzierung eines der weiteren betroffenen und eines nicht erkrankten Geschwisters wurde die Variante bestätigt.Klinisch traten hochgradige mukokutane Ulzera an Reibungsstellen auf, wobei sich die Krallen ablösten. Die histopathologische Untersuchung ergab subepidermale Spalten und mittels Elektronenmikroskopie wurde der Spalt in der Lamina lucida bestätigt. Die Post mortem Untersuchung dokumentierte ausgedehnte Läsionen in Pharynx und Larynx, wobei Granulationsgewebe und fibrinöses Exsudat die Luftwege behinderten. Eine moderate tracheale Hypoplasie trug zu dem Problem bei. Die WGS zeigte eine neue Missense Mutation in der Laminin α3-Kette XP_537297.2p(Asp2867Val), bei autosomal rezessiver Vererbung.Eine neue Variante bedingte eine generalisierte Form einer JEB mit einem stark betroffenen Phänotyp und einer einzigartigen klinischen Präsentation der Obstruktion der oberen Atemwege.背景: Junctional epidermolysis bullosa（JEB）は，基底膜領域のlamina lucidaを介した間隙を特徴とする先天性水疱性皮膚疾患の一群である。 目的: 本研究の目的は、重度の上気道病変を有する子犬集団における先天性機械的水疱性疾患の臨床的および形態学的特徴を明らかにし，関連する遺伝子変異を同定することであった。 供試動物: オーストラリアン・キャトル・ドッグとの交配で生まれた子犬8頭のうち、5頭に皮膚脆弱性の兆候が見られた。3頭は死産し、1頭は生後1ヶ月で死亡した。生き残った2頭の子犬は、水ぶくれのある皮膚病と重度の呼吸困難を呈していた。さらに、罹患していない1頭の同腹仔を診察し、遺伝子検査のために血液を採取した。 材料と方法: 死後検査、病理組織学的評価および電子顕微鏡検査を行った。罹患子犬1頭の全ゲノム塩基配列（WGS）を、55種の犬522頭のデータベースと比較し、バリアント解析を行った。さらに罹患した1頭の同腹仔と罹患していない1頭の同腹仔のサンガーシークエンス法により、変異が確認された。 結果: 臨床的には、重度の粘膜皮膚潰瘍が摩擦部位に発生し、爪が剥がれた。病理組織学的には表皮下の間隙を認め、電子顕微鏡ではlamina lucidaの間隙が確認された。死後検査では、肉芽組織および線維性滲出液が気道を塞いでいる広範囲の咽頭および喉頭の病変が記録された。中等度の気管低形成が認められた。WGSの結果、ラミニンα3鎖のXP_537297.2p(Asp2867Val)という新規ミスセンス変異が見つかり、常染色体劣性遺伝であることが判明した。 結論と臨床的妥当性: 新規変異は、上気道閉塞というユニークな臨床症状を伴うJEBの全般的で重篤な表現型の原因となった。.背景: 交界性大疱性表皮松解症(Junctional epidermolysis bullosa，JEB)是一组先天性水疱性皮肤病，以基底膜区透明层裂隙为特征。 目的: 描述一窝严重上呼吸道发病幼犬先天性机械大疱病的临床和形态学特征，并确定相关的遗传变异。 动物: 澳大利亚杂交牛犬8只同窝幼犬中的5只显示出皮肤脆弱症状。3只为死胎，1例在1月龄时死亡。2只存活幼犬表现为水疱性皮肤病和严重呼吸窘迫。此外，检查了1只未发病的同窝犬，并采集血液用于基因检测。 方法和材料: 进行尸检、组织病理学评价和电子显微镜检查。将1只发病幼犬的全基因组测序(WGS)与55个不同品种的522只犬的数据库进行比较，进行变异分析。对另外一个发病和一个未发病的同窝犬进行Sanger测序，证实了该变异。 结果: 临床上，重度皮肤粘膜溃疡发生在摩擦区域，伴爪脱落。组织病理学结果显示表皮下裂隙，电子显微镜检查证实透明层开裂。尸检记录了广泛的咽部和喉部病变，伴有肉芽组织和纤维蛋白性渗出物阻塞气道。导致中度气管发育不全。WGS揭示了层粘连蛋白α3-链XP_537297.2p(Asp2867Val)的一个新的错义变体，具有常染色体隐性遗传模式。 结论和临床相关性: 种新变体引起JEB的广泛和严重表型，具有上呼吸道阻塞的独特临床表现。.A epidermólise bolhosa juncional (EBJ) é um grupo de doenças cutâneas congênitas apresentando lesões bolhosas caracterizadas por fissuras ao longo da lâmina lúcida da zona da membrana basal.Detalhar as características clínicas e morfológicas de uma doença mecanobolhosa congênita em uma ninhada de filhotes de cães com comprometimento respiratório superior grave e identificar uma variante genética associada.Cinco dos oito filhotes em uma ninhada com cães boideieros australianos mestiços apresentaram sinais de fragilidade da pele. Três nasceram mortos e um morreu com um mês de idade. Os dois cachorros sobreviventes apresentaram dermatopatia bolhosa e dificuldade respiratória grave. Além disso, um irmão não afetado foi examinado e o sangue foi obtido para teste genético. MÉTODOS E MATERIAIS: Foram realizados exame post-mortem, avaliação histopatológica e microscopia eletrônica. O sequenciamento do genoma completo (WGS) de um filhote afetado foi comparado a um banco de dados de 522 cães de 55 raças diferentes para análise de variantes. O sequenciamento de Sanger de um irmão afetado adicional e um irmão não afetado confirmou a variante.Clinicamente, úlceras mucocutâneas graves ocorreram em áreas de fricção com arranhadura pelas unhas. Os resultados histopatológicos revelaram fissuras subepidérmicas e a microscopia eletrônica confirmou a fissura na lâmina lúcida. O exame post-mortem documentou lesões laríngeas e faríngeas extensas com tecido de granulação e exsudato fibrinoso obscurecendo as vias aéreas. Hipoplasia traqueal moderada contribuiu. O WGS revelou uma nova variante missense na cadeia α3 da laminina XP_537297.2p (Asp2867Val), com um modo de herança autossômico recessivo. CONCLUSÃO E RELEVÂNCIA CLÍNICA: Uma nova variante causou um fenótipo generalizado e grave de EBJ com uma apresentação clínica única de obstrução das vias aéreas superiores.

Background Familial hypertrophic cardiomyopathy is a common inherited cardiovascular disorder in people. Many causal mutations have been identified, but about 40% of cases do not have a known causative mutation. Mutations in the ALMS1 gene are associated with the development of Alstrom syndrome, a multisystem familial disease that can include cardiomyopathy (dilated, restrictive). Hypertrophic cardiomyopathy has not been described. The ALMS1 gene is a large gene that encodes for a ubiquitously expressed protein. The function of the protein is not well understood although it is believed to be associated with energy metabolism and homeostasis, cell differentiation and cell cycle control. The ALMS1 protein has also been shown to be involved in the regulation of cell cycle proliferation in perinatal cardiomyocytes. Although cardiomyocyte cell division and replication in mammals generally declines soon after birth, inhibition of ALMS1 expression in mice lead to increased cardiomyocyte proliferation, and deficiency of Alstrom protein has been suggested to impair post-natal cardiomyocyte cell cycle arrest. Here we describe the association of familial hypertrophic cardiomyopathy in Sphynx cats with a novel ALMS1 mutation. Results A G/C variant was identified in exon 12 (human exon 13) of the ALMS1 gene in affected cats and was positively associated with the presence of hypertrophic cardiomyopathy in the feline population (p p Conclusion This study demonstrates a novel form of cardiomyopathy associated with ALMS1 in the cat. Familial hypertrophic cardiomyopathy is a disease of genetic heterogeneity; many of the known causative genes encoding for sarcomeric proteins. Our findings suggest that variants in genes involved with cardiac development and cell regulation, like the ALMS1 gene, may deserve further consideration for association with familial hypertrophic cardiomyopathy.

Background A cohort of related miniature dachshund dogs with exercise intolerance, stiff gait, dysphagia, myoglobinuria, and markedly elevated serum creatine kinase activities were identified. Methods Muscle biopsy histopathology, immunofluorescence microscopy, and western blotting were combined to identify the specific pathologic phenotype of the myopathy, and whole genome SNP array genotype data and whole genome sequencing were combined to determine its genetic basis. Results Muscle biopsies were dystrophic. Sarcoglycanopathy, a form of limb-girdle muscular dystrophy, was suspected based on immunostaining and western blotting, where α, β, and γ-sarcoglycan were all absent or reduced. Genetic mapping and whole genome sequencing identified a premature stop codon mutation in the sarcoglycan A subunit gene (SGCA). Affected dachshunds were confirmed on several continents. Conclusions This first SGCA mutation found in dogs adds to the literature of genetic bases of canine muscular dystrophies and their usefulness as comparative models of human disease.

The study of inherited diseases in companion animals has exploded over the past 15 years since the publication of the first dog genome in 2005 [...]

Laryngeal paralysis associated with a generalized polyneuropathy (LPPN) most commonly exists in geriatric dogs from a variety of large and giant breeds. The purpose of this study was to discover the underlying genetic and molecular mechanisms in a younger-onset form of this neurodegenerative disease seen in two closely related giant dog breeds, the Leonberger and Saint Bernard. Neuropathology of an affected dog from each breed showed variable nerve fiber loss and scattered inappropriately thin myelinated fibers. Using across-breed genome-wide association, haplotype analysis, and whole-genome sequencing, we identified a missense variant in the CNTNAP1 gene (c.2810G>A; p.Gly937Glu) in which homozygotes in both studied breeds are affected. CNTNAP1 encodes a contactin-associated protein important for organization of myelinated axons. The herein described likely pathogenic CNTNAP1 variant occurs in unrelated breeds at variable frequencies. Individual homozygous mutant LPPN-affected Labrador retrievers that were on average four years younger than dogs affected by geriatric onset laryngeal paralysis polyneuropathy could be explained by this variant. Pathologic changes in a Labrador retriever nerve biopsy from a homozygous mutant dog were similar to those of the Leonberger and Saint Bernard. The impact of this variant on health in English bulldogs and Irish terriers, two breeds with higher CNTNAP1 variant allele frequencies, remains unclear. Pathogenic variants in CNTNAP1 have previously been reported in human patients with lethal congenital contracture syndrome and hypomyelinating neuropathy, including vocal cord palsy and severe respiratory distress. This is the first report of contactin-associated LPPN in dogs characterized by a deleterious variant that most likely predates modern breed establishment.

The dog provides a large animal model of familial dilated cardiomyopathy for the study of important aspects of this common familial cardiovascular disease. We have previously demonstrated a form of canine dilated cardiomyopathy in the Doberman pinscher breed that is inherited as an autosomal dominant trait and is associated with a splice site variant in the pyruvate dehydrogenase kinase 4 (PDK4) gene, however, genetic heterogeneity exists in this species as well and not all affected dogs have the PDK4 variant. Whole genome sequencing of a family of Doberman pinchers with dilated cardiomyopathy and sudden cardiac death without the PDK4 variant was performed. A pathologic missense variant in the titin gene located in an immunoglobulin-like domain in the I-band spanning region of the molecule was identified and was highly associated with the disease (p

The collagen VI-related muscular dystrophies in people include a broad spectrum of diseases ranging from the severe Ullrich congenital muscular dystrophy to the mild Bethlem myopathy. Clinical features are attributable to both muscle and connective tissue and include progressive muscle weakness and respiratory failure, hyperlaxity of distal joints, and progressive contracture of large joints. Here we describe two different COL6A3 pathogenic variants in Labrador Retriever dogs that result in autosomal recessive or autosomal dominant congenital myopathies with hyperlaxity of distal joints and joint contracture, similar to the condition in people.

The purpose of this study was to report the findings of clinical and genetic evaluation of a 3-month old male Boykin spaniel (the proband) that presented with progressive weakness. The puppy underwent a physical and neurological examination, serum biochemistry and complete blood cell count, electrophysiological testing, muscle biopsy and whole genome sequencing. Clinical evaluation revealed generalized neuromuscular weakness with tetraparesis and difficulty holding the head up and a dropped jaw. There was diffuse spontaneous activity on electromyography, most severe in the cervical musculature. Nerve conduction studies were normal, the findings were interpreted as consistent with a myopathy. Skeletal muscle was grossly abnormal on biopsy and there were necklace fibers and abnormal triad structure localization on histopathology, consistent with myotubular myopathy. Whole genome sequencing revealed a premature stop codon in exon 13 of MTM1 (ChrX: 118,903,496 C > T, c.1467C>T, p.Arg512X). The puppy was humanely euthanized at 5 months of age. The puppy's dam was heterozygous for the variant, and 3 male puppies from a subsequent litter all of which died by 2 weeks of age were hemizygous for the variant. This naturally occurring mutation in Boykin spaniels causes a severe form of X-linked myotubular myopathy, comparable to the human counterpart.

Background A congenital syndrome of hearing loss and vestibular dysfunction affects Doberman Pinschers. Its inheritance pattern is suspected to be autosomal recessive and it potentially represents a spontaneous animal model of an autosomal recessive syndromic hearing loss. Hypothesis/objectives The objectives of this study were to use whole genome sequencing (WGS) to identify deleterious genetic variants in candidate genes associated with the syndrome and to study the prevalence of candidate variants among a population of unaffected Doberman Pinschers. Animals One affected Doberman Pinscher and 202 unaffected Doberman Pinschers. Methods WGS of the affected dog with filtering of variants against a database of 154 unaffected dogs of diverse breeds was performed. Confirmation of candidate variants was achieved by Sanger sequencing followed by genotyping of the control population of unaffected Doberman Pinschers. Results WGS and variant filtering identified an alteration in a gene associated with both deafness and vestibular disease in humans: protein tyrosine phosphatase, receptor type Q (PTPRQ). There was a homozygous A insertion at CFA15: 22 989 894, causing a frameshift mutation in exon 39 of the gene. This insertion is predicted to cause a protein truncation with a premature stop codon occurring after position 2054 of the protein sequence that causes 279 C-terminal amino acids to be eliminated. Prevalence of the variant was 1.5% in a cohort of 202 unaffected Doberman Pinschers; all unaffected Doberman Pinschers were heterozygous or heterozygous for the reference allele. Conclusion and clinical importance We report the identification of a genetic alteration on the PTPRQ gene that is associated with congenital hearing and vestibular disorder in a young Doberman Pinscher dog.

Myxomatous mitral valve disease (MMVD) is the most common heart disease in the dog. It is believed to be heritable in Cavalier King Charles spaniels (CKCS) and Dachshunds. Myxomatous mitral valve disease is a familial disease in human beings as well and genetic mutations have been associated with its development. We hypothesized that a genetic mutation associated with the development of the human form of MMVD was associated with the development of canine MMVD. DNA was isolated from blood samples from 10 CKCS and 10 Dachshunds diagnosed with MMVD, and whole genome sequences from each animal were obtained. Variant calling from whole genome sequencing data was performed using a standardized bioinformatics pipeline for all samples. After filtering, the canine genes orthologous to the human genes known to be associated with MMVD were identified and variants were assessed for likely pathogenic implications. No variant was found in any of the genes evaluated that was present in least eight of 10 affected CKCS or Dachshunds. Although mitral valve disease in the CKCS and Dachshund is a familial disease, we did not identify genetic cause in the genes responsible for the human disease in the dogs studied here.

A 9 mo old female intact English mastiff (case 1) presented for anorexia and vomiting for 7 days. A 7 mo old male castrated American bulldog (case 2) presented for vomiting and anorexia for 2 days without diarrhea. Both dogs were diagnosed with mesenteric volvulus based on exploratory laparotomy, which also revealed an intestinal foreign body obstruction. Case 1 required critical care support during recovery but was ultimately discharged, whereas case 2 had an uncomplicated recovery. Both were reported to be back to normal 1 wk after surgery. Case 1 survived 3 mo and then died due to a colonic torsion diagnosed by exploratory laparotomy. Case 2 has been reported to be completely normal more than 18 mo after surgery. These two cases illustrate that mesenteric volvulus can be present with a several-day history of gastrointestinal signs and that shock may be absent on presentation. This is also the first published report of mesenteric volvulus with a concurrent foreign body obstruction.

Objective To report the use of a vascular closure device (VCD) to provide rapid arterial hemostasis following percutaneous femoral arterial catheterization and diagnostic angiography in a thrombocytopenic and coagulopathic dog. Case Summary A 6-year-old female spayed Kai Ken Tora dog presented after vehicular trauma. The dog was diagnosed with traumatic pneumothorax, degloving wounds of the right antebrachium, subcutaneous hemorrhage within the axillary tissues of the left thoracic limb, and anemia and thrombocytopenia secondary to acute hemorrhage. Treatment included therapeutic thoracocentesis and open wound management of the right thoracic limb as well as packed RBC and fresh frozen plasma transfusions. Diagnostic angiography of the left brachial artery was performed via percutaneous femoral arterial access to investigate the source of a persistent axillary hematoma. The arterial access site was closed using an extraluminal VCD and hemostasis was immediate with normal femoral arterial blood flow documented by Doppler ultrasound. New or Unique Information Provided This report describes use of a VCD for arterial closure following percutaneous access in a dog with impaired hemostasis; to the authors’ knowledge, this is the first clinical report of a VCD used in a veterinary species.

OBJECTIVE To identify cardiac tissue genes and gene pathways differentially expressed between dogs with and without dilated cardiomyopathy (DCM). ANIMALS 8 dogs with and 5 dogs without DCM. PROCEDURES Following euthanasia, samples of left ventricular myocardium were collected from each dog. Total RNA was extracted from tissue samples, and RNA sequencing was performed on each sample. Samples from dogs with and without DCM were grouped to identify genes that were differentially regulated between the 2 populations. Overrepresentation analysis was performed on upregulated and downregulated gene sets to identify altered molecular pathways in dogs with DCM. RESULTS Genes involved in cellular energy metabolism, especially metabolism of carbohydrates and fats, were significantly downregulated in dogs with DCM. Expression of cardiac structural proteins was also altered in affected dogs. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that RNA sequencing may provide important insights into the pathogenesis of DCM in dogs and highlight pathways that should be explored to identify causative mutations and develop novel therapeutic interventions.

OBJECTIVE To evaluate a group of related Rhodesian Ridgebacks with a family history of sudden death for the presence of arrhythmia and to identify possible patterns of disease inheritance among these dogs. DESIGN Prospective case series and pedigree investigation. ANIMALS 25 Rhodesian Ridgebacks with shared bloodlines. PROCEDURES Pedigrees of 4 young dogs (1 female and 3 males; age, 7 to 12 months) that died suddenly were evaluated, and owners of closely related dogs were asked to participate in the study. Dogs were evaluated by 24-hour Holter monitoring, standard ECG, echocardiography, or some combination of these to assess cardiac status. Necropsy reports, if available, were reviewed. RESULTS 31 close relatives of the 4 deceased dogs were identified. Of 21 dogs available for examination, 8 (2 males and 6 females) had ventricular tachyarrhythmias (90 to 8,700 ventricular premature complexes [VPCs]/24 h). No dogs had clinical signs of cardiac disease reported. Echocardiographic or necropsy evaluation for 7 of 12 dogs deemed affected (ie, with frequent or complex VPCs or sudden death) did not identify structural lesions. Five of 6 screened parents of affected dogs had 0 to 5 VPCs/24 h (all singlets), consistent with a normal reading. Pedigree evaluation suggested an autosomal recessive pattern of inheritance, but autosomal dominant inheritance with incomplete penetrance could not be ruled out. CONCLUSIONS AND CLINICAL RELEVANCE Holter monitoring of Rhodesian Ridgebacks with a family history of an arrhythmia or sudden death is recommended for early diagnosis of disease. An autosomal recessive pattern of inheritance in the studied dogs was likely, and inbreeding should be strongly discouraged.

Application of imputation methods to accurately predict a dense array of SNP genotypes in the dog could provide an important supplement to current analyses of array-based genotyping data. Here, we developed a reference panel of 4,885,283 SNPs in 83 dogs across 15 breeds using whole genome sequencing. We used this panel to predict the genotypes of 268 dogs across three breeds with 84,193 SNP array-derived genotypes as inputs. We then (1) performed breed clustering of the actual and imputed data; (2) evaluated several reference panel breed combinations to determine an optimal reference panel composition; and (3) compared the accuracy of two commonly used software algorithms (Beagle and IMPUTE2). Breed clustering was well preserved in the imputation process across eigenvalues representing 75 % of the variation in the imputed data. Using Beagle with a target panel from a single breed, genotype concordance was highest using a multi-breed reference panel (92.4 %) compared to a breed-specific reference panel (87.0 %) or a reference panel containing no breeds overlapping with the target panel (74.9 %). This finding was confirmed using target panels derived from two other breeds. Additionally, using the multi-breed reference panel, genotype concordance was slightly higher with IMPUTE2 (94.1 %) compared to Beagle; Pearson correlation coefficients were slightly higher for both software packages (0.946 for Beagle, 0.961 for IMPUTE2). Our findings demonstrate that genotype imputation from SNP array-derived data to whole genome-level genotypes is both feasible and accurate in the dog with appropriate breed overlap between the target and reference panels.

The QIl1 gene produces a component of the Mitochondrial Contact Site and Cristae Organizing System that forms and stabilizes mitochondrial cristae junctions and is important in cellular energy production. We previously reported a family of Rhodesian Ridgebacks with cardiac arrhythmias and sudden cardiac death. Here, we performed whole genome sequencing on a trio from the family. Variant calling was performed using a standardized bioinformatics approach. Variants were filtered against variants from 247 dogs of 43 different breeds. High impact variants were validated against additional affected and unaffected dogs. A single missense G/A variant in the QIL1 gene was associated with the cardiac arrhythmia (p &lt, 0.0001). The variant was predicted to change the amino acid from conserved Glycine to Serine and to be deleterious. Ultrastructural analysis of the biceps femoris muscle from an affected dog revealed hyperplastic mitochondria, cristae rearrangement, electron dense inclusions and lipid bodies. We identified a variant in the Q1l1 gene resulting in a mitochondrial cardiomyopathy characterized by cristae abnormalities and cardiac arrhythmias in a canine model. This natural animal model of mitochondrial cardiomyopathy provides a large animal model with which to study the development and progression of disease as well as genotypic phenotypic relationships.

Objective To describe the clinical course and successful management of a febrile dog with polyarthritis, splenic vasculitis, thrombosis, and infarction that was infected with Bartonella henselae. Case Summary An 8-year-old female spayed Labrador Retriever was referred to The Ohio State University Veterinary Medical Center Emergency Service for evaluation of limping, fever, vomiting, and malaise of 4 days’ duration. Physical examination abnormalities included generalized weakness, diminished conscious proprioception, bilateral temporalis muscle atrophy, and diarrhea. Peripheral lymph nodes were normal, and there were no signs of abdominal organomegaly, joint effusion, or spinal pain. Abdominal ultrasound identified a nonocclusive splenic vein thrombus. Fine-needle aspirates of the spleen revealed pyogranulomatous inflammation, mild reactive lymphoid hyperplasia, and mild extramedullary hematopoiesis. Splenic histopathology found marked, multifocal to coalescing acute coagulation necrosis (splenic infarctions) and fibrinoid necrotizing vasculitis. Bartonella henselae DNA was amplified by polymerase chain reaction and sequenced from the splenic tissue. The dog responded favorably to antimicrobials and was healthy at the time of follow-up evaluation. New and Unique Information Provided Bartonella henselae is an incompletely characterized emerging canine pathogen. This case report establishes a potential role for this bacterium as a cause of vasculitis and thromboembolism, which have not been previously reported in association with B. henselae infection in dogs.

Background We aimed to identify mutations associated with osteochondromatosis in a litter of American Staffordshire Terrier puppies. Hypothesis We hypothesized that the associated mutation would be located in a gene that causes osteochondromatosis in humans. Animals A litter of 9 American Staffordshire puppies, their sire and dam, 3 of 4 grandparents, 26 healthy unrelated American Staffordshire Terriers, and 154 dogs of 27 different breeds. Methods Whole genome sequencing was performed on the proband, and variants were compared against polymorphisms derived from 154 additional dogs across 27 breeds, as well as single nucleotide polymorphism database 146. One variant was selected for follow-up sequencing. Parentage and genetic mosaicism were evaluated across the litter. Results We found 56,301 genetic variants unique to the proband. Eleven variants were located in or near the gene exostosin 2 (EXT2), which is strongly associated with osteochondromatosis in humans. One heterozygous variant (c.969C > A) is predicted to result in a stop codon in exon 5 of the gene. Sanger sequencing identified the identical mutation in all affected offspring. The mutation was absent in the unaffected offspring, both parents, all available grandparents, and 26 healthy unrelated American Staffordshire Terriers. Conclusions and clinical importance These findings represent the first reported mutation associated with osteochondromatosis in dogs. Because this mutation arose de novo, the identical mutation is unlikely to be the cause of osteochondromatosis in other dogs. However, de novo mutations in EXT2 are common in humans with osteochondromatosis, and by extension, it is possible that dogs with osteochondromatosis could be identified by sequencing the entire EXT2 gene.

In humans, mitral valve prolapse (MVP) is a common heritable condition. Dogs serve as a spontaneous animal model of familial MVP, with several breeds genetically predisposed. As in humans, previous studies have suggested that canine MVP may be polygenic and may be associated with alterations in the

Objective To describe the clinical presentation and successful treatment of a dog that ingested a lethal dose (approximately 330 mg/kg) of 5-fluorouracil (5-FU). Case Summary A 1-year-old male intact German Shepherd dog was presented to the Emergency Service of the Ohio State University Veterinary Medical Center after ingesting 10 g of 5% 5-FU cream. The dog rapidly developed refractory seizures and was managed by inducing heavy sedation with phenobarbital, benzodiazepines, ketamine, and propofol, necessitating 48 hours of mechanical ventilation. Seizure activity continued despite these treatments until IV administration of levetiracetam. The dog was discharged from the hospital 6 days after admission and remains neurologically normal currently, with no further seizure activity after 9 months. New Information Provided This report documents the first successful treatment of a dog that ingested > 43 mg/kg of 5-FU. In this case, the use of rapid decontamination, heavy sedation with anticonvulsant medications including levetiracetam to control seizures, and mechanical ventilation may have contributed to a positive outcome.

Primary hypoadrenocorticism, or Addison’s disease, is an autoimmune condition common in certain dog breeds that leads to the destruction of the adrenal cortex and a clinical syndrome involving anorexia, gastrointestinal upset, and electrolyte imbalances. Previous studies have demonstrated that this destruction is strongly associated with lymphocytic-plasmacytic inflammation, and that the lymphocytes are primarily T cell in origin. In this study, we used both immunohistochemistry and in situ hybridization to characterize the T cell subtypes involved. We collected postmortem specimens of 5 dogs with primary hypoadrenocorticism and 2 control dogs, and using the aforementioned techniques, showed that the lymphocytes are primarily CD4+ rather than CD8+ in origin. These findings could have important implications for improving our understanding of the pathogenesis of the disease and in searching for the underlying causative genetic polymorphisms.

Identifying regions of artificial selection within dog breeds may provide insights into genetic variation that underlies breed-specific traits or diseases—particularly if these traits or disease predispositions are fixed within a breed. In this study, we searched for runs of homozygosity (ROH) and calculated the d i statistic (which is based upon F ST) to identify regions of artificial selection in Standard Poodles using high-coverage, whole-genome sequencing data of 15 Standard Poodles and 49 dogs across seven other breeds. We identified consensus ROH regions ≥1 Mb in length and common to at least ten Standard Poodles covering 0.6 % of the genome, and d i regions that most distinguish Standard Poodles from other breeds covering 3.7 % of the genome. Within these regions, we identified enriched gene pathways related to olfaction, digestion, and taste, as well as pathways related to adrenal hormone biosynthesis, T cell function, and protein ubiquitination that could contribute to the pathogenesis of some Poodle-prevalent autoimmune diseases. We also validated variants related to hair coat and skull morphology that have previously been identified as being under selective pressure in Poodles, and flagged additional polymorphisms in genes such as ITGA2B, CBX4, and TNXB that may represent strong candidates for other common Poodle disorders.

OBJECTIVE To evaluate the effects of damage-associated molecular patterns (DAMPs) derived from disrupted mitochondria on canine splenocytes and other immune cells. SAMPLES Liver, spleen, and bone marrow samples obtained from 8 cadavers of healthy research Beagles that had been euthanized for other purposes. PROCEDURES Mitochondria were obtained from canine hepatocytes, and mitochondrial DAMPs (containing approx 75% mitochondrial proteins) were prepared. Mitochondrial DAMPs and the nuclear cytokine high-mobility group box protein 1 were applied to splenocytes, bone marrow–differentiated dendritic cells, and a canine myelomonocytic cell (DH82) line for 6 or 24 hours. Cell culture supernatants from splenocytes, dendritic cells, and DH82 cells were assayed for tumor necrosis factor α with an ELISA. Expression of tumor necrosis factor α mRNA in splenocytes was evaluated with a quantitative real-time PCR assay. RESULTS In all cell populations evaluated, production of tumor necrosis factor α was consistently increased by mitochondrial DAMPs at 6 hours (as measured by an ELISA). In contrast, high-mobility group box protein 1 did not have any independent proinflammatory effects in this experimental system. CONCLUSIONS AND CLINICAL RELEVANCE The study revealed an in vitro inflammatory effect of mitochondrial DAMPs (containing approx 75% mitochondrial proteins) in canine cells and validated the use of an in vitro splenocyte model to assess DAMP-induced inflammation in dogs. This experimental system may aid in understanding the contribution of DAMPs to sepsis and the systemic inflammatory response syndrome in humans. Further studies in dogs are needed to validate the biological importance of these findings and to evaluate the in vivo role of mitochondrial DAMPs in triggering and perpetuating systemic inflammatory states.