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BACKGROUND: The neurotransmitter serotonin (5-HT) affects valvular degeneration and dogs with myxomatous mitral valve disease (MMVD) exhibit alterations in 5-HT signaling. In Maltese dogs, 3 single nucleotide polymorphisms (SNPs) in the 5-HT transporter (SERT) gene are suggested to associate with MMVD.HYPOTHESIS/OBJECTIVES: Determine the association of SERT polymorphisms on MMVD severity and serum 5-HT concentration in Cavalier King Charles Spaniels (CKCS). Additionally, investigate the association between selected clinical and hematologic variables and serum 5-HT and assess the correlation between HPLC and ELISA measurements of serum 5-HT.ANIMALS: Seventy-one CKCS (42 females and 29 males; 7.8 [4.7;9.9] years (median [Q1;Q3])) in different MMVD stages.METHODS: This prospective study used TaqMan genotyping assays to assess SERT gene polymorphisms. Neurotransmitter concentrations were assessed by HPLC and ELISA.RESULTS: TaqMan analyses identified none of the selected SERT polymorphisms in any of the CKCS examined. Serum 5-HT was associated with platelet count (P CONCLUSIONS AND CLINICAL IMPORTANCE: Selected SERT SNPs associated with MMVD in Maltese dogs were not found in CKCS and only platelet count influenced serum 5-HT concentration. These SNPs are unlikely to be associated with MMVD pathophysiology or serum 5-HT concentration in CKCS. HPLC and ELISA serum 5-HT demonstrated good correlation but ELISA systematically underestimated 5-HT.

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.

OBJECTIVE To evaluate the frequency of variants in the pyruvate kinase dehydrogenase 4 (PDK4) and titin (TTN) genes in a group of Doberman Pinschers with dilated cardiomyopathy (DCM) and to determine whether there were unique clinical attributes to each variant. ANIMALS 48 Doberman Pinschers with DCM. PROCEDURES Doberman Pinschers with recently diagnosed DCM were identified, and genomic DNA from each was genotyped with a PCR assay for detection of PDK4 and TTN genetic variants. Dogs were grouped on the basis of whether they had the TTN variant alone, PDK4 variant alone, both variants, or neither variant. Descriptive statistics were compiled for dog age, body weight, and left ventricular dimensions and fractional shortening and for the presence of ventricular and supraventricular arrhythmias and heart failure. Results were compared across groups. RESULTS Of the 48 dogs, 28 had the TTN variant alone, 10 had both variants, 6 had neither variant, and 4 had the PDK4 variant alone. The mean age was younger for dogs with the PDK4 variant alone, compared with other dogs. However, the number of dogs with the PDK4 variant alone was very small, and there was an overlap in age across groups. No other meaningful differences were detected across groups, and independent genotype-phenotype relationships were not identified. CONCLUSIONS AND CLINICAL RELEVANCE Although findings indicated that the TTN variant was most common, 6 dogs had neither variant, and this fact supported the concept of ≥ 1 other genetic contributor to DCM in Doberman Pinschers. Future studies are warranted to evaluate genotype-phenotype relationships in Doberman Pinschers with DCM.

Background An angiotensin‐converting enzyme (ACE) gene polymorphism occurs in dogs; however, functional importance is not well studied. Hypothesis We hypothesized that dogs with the polymorphism would show alternative renin‐angiotensin aldosterone system (RAAS) pathway activation and classical RAAS pathway suppression before and after ACE‐inhibitor administration, as compared to dogs without the polymorphism that would show this pattern only after ACE‐inhibitor administration. Animals Twenty‐one dogs with mitral valve disease that were genotyped for the ACE gene polymorphism. Methods This retrospective study utilized stored samples from 8 ACE gene polymorphism‐negative (PN) dogs and 13 ACE gene polymorphism‐positive (PP) dogs before and after enalapril administration. Equilibrium analysis was performed to evaluate serum RAAS metabolites and enzyme activities. Results were compared before and after enalapril, and between groups. Results The classical RAAS pathway was suppressed and the alternative RAAS pathway was enhanced for both genotypes after administration of enalapril, with no differences before enalapril administration. Aldosterone breakthrough occurred in both PN (38%) and PP (54%) dogs despite angiotensin II suppression. Aldosterone was significantly higher (P = .02) in ACE gene PP dogs (median, 92.17 pM; IQR, 21.85‐184.70) compared to ACE gene PN dogs (median, 15.91 pM; IQR

Hypertrophic cardiomyopathy (HCM) is the most common cause of heart disease in the domestic cat with a genetic predisposition in a few breeds. In the Maine Coon and Ragdoll breeds, two variants associated with the HCM phenotype have been identified in the cardiac myosin binding protein C gene (MYBPC3; p.Ala31Pro and p.Arg820Trp respectively), and a single variant has been identified in the myosin heavy chain gene (MYH7; p.Glu1883Lys) in one domestic cat with HCM. It is not known if these variants influence the development of HCM in other cohorts of the feline population. The objective of this study was to evaluate the presence of the known MYBPC3 and MYH7 variants in a population of cats with HCM. DNA was isolated from samples collected from non-Ragdoll and non-Maine Coon domestic cats diagnosed with HCM through the North Carolina State University College of Veterinary Medicine and genotyped for the three variants. One-hundred and three DNA samples from cats with HCM were evaluated from domestic shorthair, domestic longhair and purebred cats. All samples were wt for the MYBPC3 and MYH7 variants. Although this study was limited by its inclusion of cats from one tertiary hospital, the lack of these MYBPC3 and MYH7 variants in this feline HCM population indicates that the clinical utility of genetic testing for these variants may be isolated to the two cat breeds in which these variants have been identified. Further studies to identify the causative variants for the feline HCM population are warranted.

OBJECTIVE To characterize features of myxomatous mitral valve disease (MMVD) in Miniature Schnauzers and Yorkshire Terriers. ANIMALS 69 Miniature Schnauzers and 65 Yorkshire Terriers, each with MMVD. PROCEDURES Medical record data for each dog were collected; the study period was January 2007 through December 2016. If available, radiographic data were evaluated, and a vertebral heart scale score was assigned for each dog. Statistical analysis was performed with Student t and Fisher exact tests. RESULTS Compared with Yorkshire Terriers, the prevalence of MMVD was significantly higher in Miniature Schnauzers and affected dogs were significantly younger at the time of diagnosis. Miniature Schnauzers were significantly more likely to have mitral valve prolapse and syncope, compared with Yorkshire Terriers. Yorkshire Terriers were significantly more likely to have coughing and have had previous or current treatment with cardiac medications, compared with Miniature Schnauzers. There was no statistical difference between breeds with regard to abnormally high vertebral heart scale scores or radiographic evidence of congestive heart failure. CONCLUSIONS AND CLINICAL RELEVANCE With regard to MMVD, features of the disease among Miniature Schnauzers and Yorkshire Terriers were similar, but there were also a few discernable differences between these 2 breeds and from historical findings for dogs with MMVD of other breeds. Clinical signs at the time of diagnosis differed between the 2 breeds, which may have reflected concurrent breed-specific conditions (sick sinus syndrome or airway disease [eg, tracheal collapse]). Future work should include prospective studies to provide additional information regarding the natural progression of MMVD in these dog breeds.

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.

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

Introduction Canine dilated cardiomyopathy (DCM) can result from numerous etiologies including genetic mutations, infections, toxins, and nutritional imbalances. This study sought to characterize differences in echocardiographic findings between dogs with DCM fed grain-free (GF) diets and grain-based (GB) diets. Animals Forty-eight dogs with DCM and known diet history. Methods This was a retrospective analysis of dogs with DCM from January 1, 2015 to May 1, 2018 with a known diet history. Dogs were grouped by diet (GF and GB), and the GF group was further divided into dogs eating the most common grain-free diet (GF-1) and other grain-free diets (GF-o). Demographics, diet history, echocardiographic parameters, taurine concentrations, and vertebral heart scale were compared between GB, all GF, GF-1, and GF-o groups at diagnosis and recheck. Results Dogs eating GF-1 weighed less than GB and GF-o dogs, but age and sex were not different between groups. Left ventricular size in diastole and systole was greater, and sphericity index was less for GF-1 compared with GB dogs. Diastolic left ventricular size was greater for all GF compared with that of GB dogs. Fractional shortening, left atrial size, and vertebral heart scale were not different between groups. Taurine deficiency was not identified in GF dogs, and presence of congestive heart failure was not different between groups. Seven dogs that were reevaluated after diet change (6 received taurine supplementation) had clinical and echocardiographic improvement. Conclusions Dietary-associated DCM occurs with some GF diets and can improve with nutritional management, including diet change. The role of taurine supplementation, even without deficiency, is uncertain.

Myxomatous mitral valve disease (MMVD) is the most common cardiovascular disease in the dog. The natural history of the disease is wide ranging and includes patients without clinical signs as well as those with significant clinical consequences from cardiac arrhythmias, pulmonary hypertension and/or congestive heart failure. The factors that determine which dogs remain asymptomatic and which develop clinical disease are not known. Disease characteristics could be breed or family related; some breeds of dogs, particularly the Cavalier King Charles spaniels, develop MMVD at an early age. The purpose of this study was to retrospectively characterize MMVD in the miniature poodle, a commonly affected breed in which MMVD has not been well characterized. Thirty-two miniature poodles met the inclusion criteria. Mean age was 11±three years. Clinical signs included exercise intolerance, syncope and coughing. Eighteen dogs were classified as ACVIM Stage B1, 12 as stage B2, and two as stage C. Mean vertebral heart scale (VHS) was 10.2 (±standard deviation of 0.9); 15 of 28 dogs had a VHS

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.

Hair length can be a highly variable trait within the Felis catus species, varying between and within different cat breeds. Previous research has demonstrated this variability is due to recessive mutations within the fibroblast growth factor 5 (FGF5) gene. Following a clinical genetic screen, four long-haired Maine Coons were identified that had only one copy of a known FGF5 mutation. We performed DNA sequencing on two of the Maine Coons and identified a missense mutation in FGF5 c.G>A625 p.A193T (Mutation 5, M5). Genetic screening via restriction digest was then performed on an additional 275 cats of various breeds, revealing two more Maine Coons heterozygous for M5 and a previously known mutation. No additional cases were identified after in silico analysis of 68 whole genome cat sequences from various breeds, demonstrating that this novel mutation is most likely a breed-specific variant for the Maine Coon, contributing to the longhair phenotype in about 3% of cats.

Cardiomyopathies such as dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy are common in large breed dogs and carry an overall poor prognosis. Research shows that these diseases have strong breed predilections, and selective breeding has historically been recommended to reduce the disease prevalence in affected breeds. Treatment of these diseases is typically palliative and aimed at slowing disease progression and managing clinical signs of heart failure as they develop. The discovery of specific genetic mutations underlying cardiomyopathies, such as the striatin mutation in Boxer arrhythmogenic right ventricular cardiomyopathy and the pyruvate dehydrogenase kinase 4 and titin mutations in Doberman Pinschers, has strengthened our ability to screen and selectively breed individuals in an attempt to produce unaffected offspring. The discovery of these disease-linked mutations has also opened avenues for the development of gene therapies, including gene transfer and genome-editing approaches. This review article discusses the known genetics of cardiomyopathies in dogs, reviews existing gene therapy strategies and the status of their development in canines, and discusses ongoing challenges in the clinical translation of these technologies for treating heart disease. While challenges remain in using these emerging technologies, the exponential growth of the gene therapy field holds great promise for future clinical applications.

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.

To evaluate the frequency of variants in the pyruvate kinase dehydrogenase 4 (48 Doberman Pinschers with DCM.Doberman Pinschers with recently diagnosed DCM were identified, and genomic DNA from each was genotyped with a PCR assay for detection ofOf the 48 dogs, 28 had theAlthough findings indicated that the

Introduction Dilated cardiomyopathy (DCM) in dogs has been associated with feeding of grain-free (GF), legume-rich diets. Some dogs with presumed diet-associated DCM have shown improved myocardial function and clinical outcomes following a change in diet and standard medical therapy. Hypothesis Prior GF (pGF) diet influences reverse cardiac remodeling and clinical outcomes in dogs with DCM and congestive heart failure (CHF). Animals and methods A retrospective study was performed with 67 dogs with DCM and CHF for which diet history was known. Dogs were grouped by diet into pGF and grain-inclusive (GI) groups. Dogs in the pGF group were included if diet change was a component of therapy. Survival was analyzed using Kaplan–Meier curves and the Cox proportional-hazards model. Results The median survival time was 344 days for pGF dogs vs. 253 days for GI dogs (P = 0.074). Statistically significant differences in median survival were identified when the analysis was limited to dogs surviving longer than one week (P = 0.033). pGF dogs had a significantly worse outcome the longer a GF diet was fed prior to diagnosis (P = 0.004) or if they were diagnosed at a younger age (P = 0.017). pGF dogs showed significantly greater improvement in normalized left ventricular internal diastolic diameter (P = 0.038) and E-point septal separation (P = 0.031) measurements and significant decreases in their furosemide (P = 0.009) and pimobendan (P Conclusions pGF dogs that survived at least one week after diagnosis of DCM, treatment of CHF, and diet change had better clinical outcomes and showed reverse ventricular remodeling compared to GI dogs.

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.

Arrhythmogenic right ventricular cardiomyopathy is an inheritable form of myocardial disease characterized most commonly by ventricular tachycardias, syncope, and sometimes systolic dysfunction and heart failure. A genetic mutation in the striatin gene has been identified in many affected dogs. Dogs with only one copy of the mutation (heterozygous) have a variable prognosis, with many dogs remaining asymptomatic or being successfully managed on antiarrhythmic drugs for years. Dogs that are homozygous for the mutation seem to have a worse prognosis.

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 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.

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Cardiac arrhythmias often are transient and might not be detected using conventional electrocardiographic (ECG) techniques. The adhesive patch monitor (APM) is a single-lead, lightweight, up to 14-day continuous ambulatory ECG monitor. This study aimed to prospectively assess its usability in four boxer dogs considered either to be healthy or to have arrhythmogenic right ventricular cardiomyopathy. Optimal recording was obtained by placing the APM on the left side of the animal’s thorax, at the fifth intercostal space, slightly dorsal to the costochondral junction, and oriented either vertically or parallel to the long axis of the heart. In three dogs, the APM remained attached for 14 days. One dog removed the APM after 59 hr. Skin irritation was documented in all dogs and resolved spontaneously after removal of the APM. The analyzable time was >93% of the total wear time and recordings provided an unambiguous rhythm diagnosis at rest. Walking, running, or playing caused intermittent motion artifact that could impair ECG interpretation. APM results were comparable to those obtained with 24-hr Holter monitoring. Extended continuous ECG monitoring with the APM is feasible in boxer dogs and provides interpretable recordings.

The regenerative potential of cardiosphere-derived cells (CDCs) for ischaemic heart disease has been demonstrated in mice, rats, pigs and a recently completed clinical trial. The regenerative potential of CDCs from dog hearts has yet to be tested. Here, we show that canine CDCs can be produced from adult dog hearts. These cells display similar phenotypes in comparison to previously studied CDCs derived from rodents and human beings. Canine CDCs can differentiate into cardiomyocytes, smooth muscle cells and endothelial cells in vitro. In addition, conditioned media from canine CDCs promote angiogenesis but inhibit cardiomyocyte death. In a doxorubicin-induced mouse model of dilated cardiomyopathy (DCM), intravenous infusion of canine CDCs improves cardiac function and decreases cardiac fibrosis. Histology revealed that injected canine CDCs engraft in the mouse heart and increase capillary density. Out study demonstrates the regenerative potential of canine CDCs in a mouse model of DCM., Journal of Cellular and Molecular Medicine, 19(8), pp.1805-1813; 2015

Background:\ud A 5-year-old, healthy English Springer Spaniel died suddenly 4 months after delivering a litter of 7 puppies. Within 4 months of the dam's death, 3 offspring also died suddenly.\ud \ud Hypothesis:\ud Abnormal cardiac repolarization, caused by an inherited long QT syndrome, is thought to be responsible for arrhythmias leading to sudden death in this family.\ud \ud Animals:\ud Four remaining dogs from the affected litter and 11 related dogs.\ud \ud Methods:\ud Physical examination and resting ECG were done on the littermates and 9 related dogs. Additional tests on some or all littermates included echocardiogram with Doppler, Holter monitoring, and routine serum biochemistry. Blood for DNA sequencing was obtained from all 15 dogs.\ud \ud Results:\ud Three of 4 littermates examined, but no other dogs, had prolonged QT intervals with unique T-wave morphology. DNA sequencing of the KCNQ1 gene identified a heterozygous single base pair mutation, unique to these 3 dogs, which changes a conserved amino acid from threonine to lysine and is predicted to change protein structure.\ud \ud Conclusions and Clinical Importance:\ud This family represents the first documentation in dogs of spontaneous familial QT prolongation, which was associated with a KCNQ1 gene mutation and sudden death. Although the final rhythm could not be documented in these dogs, their phenotypic manifestations of QT interval prolongation and abnormal ECG restitution suggested increased risk for sudden arrhythmic death. The KCNQ1 gene mutation identified is speculated to impair the cardiac repolarizing current IKs, similar to KCNQ1 mutations causing long QT syndrome 1 in humans.

Objectives: Myxomatous mitral valve disease (MMVD) is the most common heart disease in the dog. It is particularly common in the Cavalier King Charles Spaniel (CKCS) breed and affected dogs are frequently managed with angiotensin-converting enzyme inhibitors (ACE-I). We have previously identified a canine ACE gene polymorphism associated with a decrease in angiotensin-converting enzyme (ACE) activity. The aim of this study was to evaluate for the prevalence of the ACE polymorphism in CKCS with mitral valve disease and to determine whether the presence of the polymorphism is associated with alterations in ACE activity at different stages of cardiac disease. Methods: Seventy-three dogs with a diagnosis of mitral valve disease were evaluated and a blood sample was drawn for ACE polymorphism genotyping and ACE activity measurement. Results: Forty-three dogs were homozygous for the ACE polymorphism; five were heterozygous and 25 were homozygous wild type. The mean age and the median severity of disease were not different for dogs with the polymorphism and dogs with the wild-type sequence. The median baseline ACE activity was significantly lower for the ACE polymorphism (27.0 U/l) than the wild-type sequence dogs (31.0 U/l) (P=0.02). Dogs with more severe disease and the ACE polymorphism had significantly lower levels of ACE activity than dogs with the wild-type sequence (P=0.03). Conclusion: The CKCS appears to have a high prevalence of the ACE variant. Dogs with the ACE variant had lower levels of ACE activity even in more advanced mitral valve disease than dogs without the variant. The clinical significance of this finding and its impact on the need for ACE-I in dogs with the polymorphism and heart disease deserves further study.

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.

OBJECTIVE\ud \ud The objective of this study was to evaluate angiotensin-converting enzyme (ACE) activity in dogs and with and without an ACE polymorphism in the canine ACE gene, before and after treatment with an ACE inhibitor.\ud \ud METHODS\ud \ud Thirty-one dogs (20 wild-type, 11 ACE polymorphism) with heart disease were evaluated with ACE activity measurement and systolic blood pressure before and after administration of an ACE inhibitor (enalapril).\ud \ud RESULTS\ud \ud Median pre-treatment ACE activity was significantly lower for ACE polymorphism dogs than for dogs with the wild-type sequence ( P=0.007). After two weeks of an ACE inhibitor, ACE activity was significantly reduced for both genotypes (wild-type, P

Objective—To assess survival time and adverse events related to the administration of pimobendan to cats with congestive heart failure (CHF) secondary to hypertrophic cardiomyopathy (HCM) or hypertrophic obstructive cardiomyopathy (HOCM). Design—Retrospective case-control study. Animals—27 cats receiving treatment with pimobendan and 27 cats receiving treatment without pimobendan. Procedures—Medical records between 2003 and 2013 were reviewed. All cats with HCM or HOCM treated with a regimen that included pimobendan (case cats) were identified. Control cats (cats with CHF treated during the same period with a regimen that did not include pimobendan) were selected by matching to case cats on the basis of age, sex, body weight, type of cardiomyopathy, and manifestation of CHF. Data collected included signalment, physical examination findings, echocardiographic data, serum biochemical values, and survival time from initial diagnosis of CHF. Kaplan-Meier survival curves were constructed and compared by means of a log rank test. Results—Cats receiving pimobendan had a significant benefit in survival time. Median survival time of case cats receiving pimobendan was 626 days, whereas median survival time for control cats not receiving pimobendan was 103 days. No significant differences were detected for any other variable. Conclusions and Clinical Relevance—The addition of pimobendan to traditional treatment for CHF may provide a substantial clinical benefit in survival time for HCM-affected cats with CHF and possibly HOCM-affected cats with CHF.

Background Boxer arrhythmogenic right ventricular cardiomyopathy (ARVC) is a disease that may result in sudden death or heart failure. Hypothesis/objectives To prospectively study the natural history of Boxer ARVC. Animals 72 dogs (49 ARVC, 23 controls). Methods Boxers >1 year of age were recruited for annual reevaluation. Controls were defined as being ≥6 years of age and having

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

Myocardial disease in the Boxer dog is characterized by 1 of 2 clinical presentations, dilated cardiomyopathy (DCM) characterized by ventricular systolic dysfunction, dilatation and tachyarrhythmias, and arrhythmogenic right ventricular cardiomyopathy (ARVC) characterized by ventricular tachyarrhythmias, syncope, and sudden death. Boxer ARVC has been associated with a deletion in the striatin gene in some families. We hypothesized that both presentations represent a single disease, and the development of DCM in the Boxer is associated with the striatin deletion. Thirty-three adult Boxer dogs with DCM, 29 adult Boxer dogs with the striatin deletion and ARVC, and 16 Boxers without cardiac disease. DNA samples were evaluated for the striatin deletion. Association of the deletion with the DCM phenotype was tested by a Fisher's exact test. T-tests were used to evaluate potential differences between the positive heterozygous and positive homozygous groups with DCM with regard to age, LVIDD, LVIDS, and FS%. Thirty of 33 dogs with DCM were positive for the striatin deletion. The striatin mutation and the homozygous genotype were strongly associated with the DCM phenotype (P < .001 and P = .005). There was no statistical difference between the heterozygous and homozygous groups with regard to age and echocardiographic measurements. This study demonstrates an association between DCM in the Boxer dog and the striatin mutation, particularly with the homozygous genotype. The observation that 3/33 dogs developed DCM and lacked the striatin mutation suggests that there is at least 1 other cause of DCM in the Boxer dog.

Cardiosphere‐derived cells (CDCs) have been shown to reduce scar size and increase viable myocardium in human patients with mild/moderate myocardial infarction. Studies in rodent models suggest that CDC therapy may confer therapeutic benefits in patients with non‐ischaemic dilated cardiomyopathy (DCM). We sought to determine the safety and efficacy of allogeneic CDC in a large animal (canine) model of spontaneous DCM. Canine CDCs (cCDCs) were grown from a donor dog heart. Similar to human CDCs, cCDCs express CD105 and are slightly positive for c‐kit and CD90. Thirty million of allogeneic cCDCs was infused into the coronary vessels of Doberman pinscher dogs with spontaneous DCM. Adverse events were closely monitored, and cardiac functions were measured by echocardiography. No adverse events occurred during and after cell infusion. Histology on dog hearts (after natural death) revealed no sign of immune rejection from the transplanted cells.

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.

Immune-mediated diseases are common and life-threatening disorders in dogs. Many canine immune-mediated diseases have strong breed predispositions and are believed to be inherited. However, the genetic mutations that cause these diseases are mostly unknown. As many immune-mediated diseases in humans share polymorphisms among a common set of genes, we conducted a candidate gene study of 15 of these genes across four immune-mediated diseases (immune-mediated hemolytic anemia, immune-mediated thrombocytopenia, immune-mediated polyarthritis (IMPA), and atopic dermatitis) in 195 affected and 206 unaffected dogs to assess whether causative or predictive polymorphisms might exist in similar genes in dogs. We demonstrate a strong association (Fisher's exact p = 0.0004 for allelic association, p = 0.0035 for genotypic association) between two polymorphic positions (10 bp apart) in exon 2 of one allele in DLA-79, DLA-79*001:02, and multiple immune-mediated diseases. The frequency of this allele was significantly higher in dogs with immune-mediated disease than in control dogs (0.21 vs. 0.12) and ranged from 0.28 in dogs with IMPA to 0.15 in dogs with atopic dermatitis. This allele has two non-synonymous substitutions (compared with the reference allele, DLA-79*001:01), resulting in F33L and N37D amino acid changes. These mutations occur in the peptide-binding pocket of the protein, and based upon our computational modeling studies, are likely to affect critical interactions with the peptide N-terminus. Further studies are warranted to confirm these findings more broadly and to determine the specific mechanism by which the identified variants alter canine immune system function.

Familial dilated cardiomyopathy is a primary myocardial disease that can result in the development of congestive heart failure and sudden cardiac death. Spontaneous animal models of familial dilated cardiomyopathy exist and the Doberman pinscher dog is one of the most commonly reported canine breeds. The objective of this study was to evaluate familial dilated cardiomyopathy in the Doberman pinscher dog using a genome-wide association study for a genetic alteration(s) associated with the development of this disease in this canine model. Genome-wide association analysis identified an area of statistical significance on canine chromosome 14 (p(raw) = 9.999e-05 corrected for genome-wide significance), fine-mapping of additional SNPs flanking this region localized a signal to 23,774,190-23,781,919 (p = 0.001) and DNA sequencing identified a 16-base pair deletion in the 5' donor splice site of intron 10 of the pyruvate dehydrogenase kinase 4 gene in affected dogs (p < 0.0001). Electron microscopy of myocardium from affected dogs demonstrated disorganization of the Z line, mild to moderate T tubule and sarcoplasmic reticulum dilation, marked pleomorphic mitochondrial alterations with megamitochondria, scattered mitochondria with whorling and vacuolization and mild aggregates of lipofuscin granules. In conclusion, we report the identification of a splice site deletion in the PDK4 gene that is associated with the development of familial dilated cardiomyopathy in the Doberman pinscher dog.