Linkage of dermatomyositis in the Shetland Sheepdog to chromosome 35

Genomic association and further characterisation of faecal immunoglobulin A deficiency in German Shepherd dogs

BACKGROUND

Immunoglobulin A (IgA) deficiency, chronic enteropathies and exocrine pancreatic insufficiency (EPI) have a high prevalence in German Shepherd dogs (GSD). This prospective study determined the prevalence of faecal IgA deficiency (IgAD) in GSD and investigated several candidate genes and the canine genome for a region or locus co-segregating with IgAD in GSD. Faecal IgA concentrations were quantified and genomic DNA was extracted from 8 GSD with an undetectable faecal IgA (classified as IgAD) and 80 non-IgAD GSD. The canine minimal screening set II microsatellite markers were genotyped, with evidence of an association at p < 1.0 × 10-3 . Faecal IgA concentrations were also tested for an association with patient clinical and biochemical variables.

RESULTS

Allele frequencies observed using the candidate gene approach were not associated with faecal IgAD in GSD. In the genome-wide association study (GWAS), the microsatellite marker FH2361 on canine chromosome 33 approached statistical significance for a link with IgAD in GSD (p = 1.2 × 10-3 ). A subsequent GWAS in 11 GSD with EPI and 80 control GSD revealed a significant association between EPI and FH2361 (p = 8.2 × 10-4 ).

CONCLUSIONS

The lack of an association with the phenotype of faecal IgAD in GSD using the candidate gene approach and GWAS might suggests that faecal IgAD in GSD is a relative or transient state of deficiency. However, the prevalence of faecal IgAD in GSD appears to be low (<3%). The relationship between faecal IgAD, EPI and loci close to FH2361 on canine chromosome 33 in GSD warrants further investigation.

Familiäres Auftreten der Dermatomyositis bei Working Kelpies

Acht eng verwandte Mitglieder einer Linie von Working Kelpies zeigten Symptome einer Dermatomyositis in Form von Alopezie, Krusten, Ulzerationen der Haut, Depigmentation von Nasenspiegel und Lefzen, Onychodystrophie und Muskelatrophie, vor allem der Kaumuskeln. Die Symptome waren bei den betroffenen Tieren unterschiedlich stark oder nur teilweise ausgeprägt. Die klinische Diagnose wurde bei drei Hunden durch histologische Untersuchung von Hautbioptaten, nicht jedoch Muskelbioptaten bestätigt. Therapeutisch kamen verschiedene immunmodulatorische Medikamente (Steroide, Ciclosporin, Mycophenolat-Mofetil, Pentoxifyllin, Doxycylin/Niacinamid, Omega-3-Fettsäuren, Vitamin E) mit unterschiedlichem Erfolg zum Einsatz. Bei der Dermatomyositis handelt es sich um eine immunvermittelte Erkrankung mit genetischem Hintergrund bei Mensch und Hund. Die verantwortlichen Gene sind weitgehend unbekannt. Für die Hunderassen Collie und Shetland Sheepdog besteht eine Prädisposition. Zudem wird eine familiäre Häufung beim Beauceron beschrieben. Da die Rasse Working Kelpie im 19. Jahrhundert aus schottischen Hunden des Collie-Typs entstanden ist, wäre eine genetische Prädisposition für die Dermatomyositis erklärbar.

Clinical features of idiopathic inflammatory polymyopathy in the Hungarian Vizsla

BACKGROUND

A retrospective study of the clinicopathological features of presumed and confirmed cases of idiopathic inflammatory polymyopathy in the Hungarian Vizsla dog and guidelines for breeding.

RESULTS

369 medical records were reviewed (1992-2013) and 77 Hungarian Vizslas were identified with a case history consistent with idiopathic inflammatory polymyopathy. Inclusion criteria were: group 1 (confirmed diagnosis); histopathology and clinical findings compatible with an inflammatory polymyopathy and group 2 (probable diagnosis); clinical findings compatible with a polymyopathy including dysphagia, sialorrhea, temporal muscle atrophy, elevated serum creatine kinase (CK) activity, and sufficient clinical history to suggest that other neuromuscular disorders could be ruled out. Some group 2 dogs had muscle biopsy, which suggested muscle disease but did not reveal an inflammatory process. The mean age of onset was 2.4 years; male dogs were slightly overrepresented. Common presenting signs were dysphagia, sialorrhea, masticatory muscle atrophy, and regurgitation. Common muscle histopathological findings included degenerative and regenerative changes, with multifocal mononuclear cell infiltration with lymphoplasmacytic myositis of variable severity. A positive response to immunosuppressive treatment supported an immune-mediated aetiology. The mean age at death and survival time were 6.4 and 3.9 years, respectively. Recurrence of clinical signs and aspiration pneumonia were common reasons for euthanasia.

CONCLUSIONS

Diagnosis of Vizsla idiopathic inflammatory polymyopathy can be challenging due to lack of specific tests, however the presence of dysphagia, regurgitation and masticatory muscle atrophy in this breed with negative serological tests for masticatory muscle myositis and myasthenia gravis, along with muscle biopsies suggesting an inflammatory process, support the diagnosis. However, there is an urgent need for a more specific diagnostic test. The average of inbreeding coefficient (CoI) of 16.3% suggests an increased expression of a Dog Leukocyte Antigen Class II haplotype, leading to an increased disease risk. The prognosis remains guarded, as treatment can only manage the disease. Recurrence of clinical signs and perceived poor quality of life are the most common reasons for humane euthanasia.

Association of an MHC class II haplotype with increased risk of polymyositis in Hungarian Vizsla dogs

A breed-specific polymyositis is frequently observed in the Hungarian Vizsla. Beneficial clinical response to immunosuppressive therapies has been demonstrated which points to an immune-mediated aetiology. Canine inflammatory myopathies share clinical and histological similarities with the human immune-mediated myopathies. As MHC class II associations have been reported in the human conditions we investigated whether an MHC class II association was present in the canine myopathy seen in this breed. 212 Hungarian Vizsla pedigree dogs were stratified both on disease status and degree of relatedness to an affected dog. This generated a group of 29 cases and 183 "graded" controls: 93 unaffected dogs with a first degree affected relative, 44 unaffected dogs with a second degree affected relative, and 46 unaffected dogs with no known affected relatives. Eleven DLA class II haplotypes were identified, of which, DLA-DRB1*02001/DQA1*00401/DQB1*01303, was at significantly raised frequency in cases compared to controls (OR = 1.92, p = 0.032). When only control dogs with no family history of the disease were compared to cases, the association was further strengthened (OR = 4.08, p = 0.00011). Additionally, a single copy of the risk haplotype was sufficient to increase disease risk, with the risk substantially increasing for homozygotes. There was a trend of increasing frequency of this haplotype with degree of relatedness, indicating low disease penetrance. These findings support the hypothesis of an immune-mediated aetiology for this canine myopathy and give credibility to potentially using the Hungarian Vizsla as a genetic model for comparative studies with human myositis.

Disseminated idiopathic myofasciitis in ferrets

First described in 2003, disseminated idiopathic myofasciitis (DIM) has emerged as a new disease in young, domestic ferrets. DIM is a severe inflammatory condition that affects primarily muscles and surrounding connective tissues. The disease is characterized by rapid onset of clinical signs, high fever, neutrophilic leukocytosis, and general lack of response to therapeutic intervention. Until recently DIM was considered fatal, but a few surviving ferrets indicate there may be an effective treatment protocol. DIM is suspected to be an immune-mediated disease, but the etiopathogenesis is not known. This article reviews clinical and pathologic findings in DIM patients, covers recommended diagnostic procedures and clinical management of ferrets with DIM, and discusses potential etiologies for this newly recognized disease in ferrets.

Analysis of gene transcript profiling and immunobiology in Shetland sheepdogs with dermatomyositis

Dermatomyositis (DM) is a canine and human inflammatory disease of the skin and muscle that is thought to be autoimmune in nature. In dogs, DM occurs most often in the rough collie and Shetland sheepdog. Characteristic skin lesions typically develop on the face, ears, tail, and distal extremities. The severity of lesions varies and is thought to increase with stressful stimuli. Previous studies in the collie suggest that DM is inherited in an autosomal dominant fashion with incomplete penetrance. The work presented here concerns gene transcripts profiling and immunobiology of DM in the Shetland sheepdog. Gene transcript profiles were generated for affected and normal skin using a canine-specific oligonucleotide array having 49,929 probe sets. Two-hundred and eight-five gene transcripts, many of which are involved in immune function, were found to be differentially regulated in these tissues. Also reported are Western blot, immunohistochemistry, and immunofluorescence analyses which showed that staining patterns with sera from normal and affected dogs are quite similar. While our work suggests that canine DM is a disease that may be immune mediated, it did not detect the production of specific disease-associated autoantibodies.