Cerebellar Abiotrophy in Australian Working Kelpies Is Associated with Two Major Risk Loci.

An autosomal recessive form of inherited cerebellar abiotrophy (CA) that is characterized by a degeneration of Purkinje and granule cells in the cerebellar cortex occurs in the Australian working kelpie dog breed. The clinical signs of CA include ataxia, head tremor, motor in-coordination, wide-based stance, and high-stepping gait. Investigation of clinical and pathological features indicated two closely related diseases with differences in age of onset. A genome-wide association study on 45 CA affected and 290 normal healthy Kelpies identified two significantly associated loci, one on CFA9 and a second on CFA20. Dogs homozygous for the risk haplotype on CFA20 (23 dogs) show clinical signs before ten weeks of age. Missense variants in the sixth exon of disruptor of telomeric silencing 1-like (DOT1Lp.R200Q) and in the only exon of Leucine Rich Repeat And Ig Domain Containing 3 (LINGO3p.R359C), both on CFA20, segregate with the associated risk marker which has incomplete penetrance (42%). Affected dogs homozygous for the risk haplotype on CFA9 have later onset ataxia. A missense variant in exon 5 of Vacuole Membrane Protein 1 (VMP1 p.P160Q) on CFA9 segregates as a fully penetrant Mendelian recessive with later-onset CA. Across mammals, the variety of causative loci so far identified as influencing cerebellar disorders reinforces the complexity of the pathways that contribute to cerebellar development and function, and to the pathophysiological mechanisms that may lead to cerebellar ataxia.

Profiling of genetic markers useful for breeding decision in Selle Francais horse.

Genetic disorders are recognised as hereditary diseases with the most significant economic impact on horse breeding, causing important foal losses, costs of treatments of horses, and maintenance of the mare during the pregnancy. The Selle Francais horses are recognized in many countries and are showing great results in equestrian sports around the world (dressage, show jumping and eventing). The study aimed to detect the presence of three mutant alleles associated with inherited diseases including Fragile Foal Syndrome (FFS), Cerebellar Abiotrophy (CA), Polysaccharide Storage Myopathy (PSSM1) and variant impacting gait type in DMRT3. This trait is important for breeding decision in Selle Francais horses and sheds new light on genetic potential and risks on this breed. The genotyping was performed on 91 Selle Francais horses using PCR-RFLP (for POLD1; GYS1 and DMRT3 genes) and PCR-ACRS (TOE1 gene) methods. The presented report indicated the presence of mutant allele A casual for PSSM1 and allele T associated with FFS syndrome occurrence, in 4% and 6% of analysed horses, respectively. Regarding CA, the present survey did not register any cases of this genetic disorder in Selle Francais horses. Our results show also that about 1% of all the Sell Francais horses studied carry the A allele of DMRT3 gene. The present findings have provided data for these fulness of monitoring genetic diseases and gait type in the investigated breed to avoid losses of offspring.

Paradoxical Vestibular Syndrome Caused by a Presumptive Cerebellar Infarction in a Rabbit.

A 6-year-old, female spayed rabbit (Oryctolagus cuniculus) presented with right paradoxical vestibular signs. Magnetic resonance imaging was performed and findings were consistent with an ischemic infarct of the cerebellum. The patient improved gradually and was free of clinical signs at the time this article was written. To the authors' knowledge this is the first case report of a paradoxical vestibular syndrome in a rabbit secondary to a presumptive ischemic infarct. Strokes should be included in the differential diagnosis of central vestibular syndrome in rabbits.

Feline Phaeohyphomycotic Cerebellitis Caused by Cladosporium cladosporioides-complex: Case Report and Review of Literature.

Cerebellar phaeohyphomycosis was diagnosed in an 8-year-old neutered male domestic cat. Gross lesions were limited to the cerebellum, which had a focally extensive dark brown-black, soft, irregular area affecting the cortex and white matter of the left hemisphere and extending to the reticular formation. Microscopically, multifocal pyogranulomatous meningoencephalitis with intralesional pigmented fungal hyphae effaced the cerebellar grey and white matter. Fungal hyphae were 3-6 µm in diameter, septate and non-dichotomously branched, with parallel, thin and slightly bulbous walls. Polymerase chain reaction for the internal transcribed spacer 1-2 ribosomal RNA genes was performed on tissue samples from formalin-fixed and paraffin wax-embedded sections of cerebellum. Nucleotide sequence analysis of the amplified fragment identified the fungal agent as Cladosporium cladosporioides. This is the first confirmed report of cerebellar phaeohyphomycosis attributable to C. cladosporioides-complex in a domestic cat.

Genetic screening for cerebellar abiotrophy, severe combined immunodeficiency and lavender foal syndrome in Arabian horses in Poland.

The highly selective breeding of Arabian horses results in inbreeding depression and genetic disorders, thereby causing significant economic loss. The Polish population of Arabians has a great impact on many breeding programmes. The aim of the current study was to monitor genetic variants involved in the most common genetic disorders of this breed. A total of 808 elite Arabian horses were screened for cerebellar abiotrophy (CA), severe combined immunodeficiency (SCID) and lavender foal syndrome (LFS) genetic disorders by Sanger sequencing and allelic discrimination methods. The investigated population was clear of LFS. The unfavourable SCID allele was detected in three heterozygous horses (q = 0.00185). Regarding CA, the minor allele frequency was q = 0.04029. This is the first report of SCID carriers in Poland. This investigation demonstrates the value of genetic testing to support breeding decisions and to facilitate genetic disease monitoring.

Late onset of cerebellar cortical degeneration in a Magellanic penguin (Spheniscus magellanicus).

An 8-year-old female Magellanic penguin (Spheniscus magellanicus) started to show epilepsy-like seizures. Subsequent magnetic resonance imaging (MRI) examinations did not reveal any responsible lesions. The neurological symptoms worsened at the age of 10. This penguin became recumbent and died 6 months later after the apparition of the recumbency. At necropsy, only multiple yellowish necrotic lesions in the air sacs and lungs were found. Histopathological evaluation of the brain showed a marked loss of Purkinje cells and many hypertrophied parvalbumin-positive basket/stellate cells were seen in the cerebellar cortex. Calbindin immunohistochemistry demonstrated disrupted arrangement of dendrites in the Purkinje cells. This case was diagnosed as cerebellar cortical degeneration with a very late onset and a slow progression in a Magellanic penguin.

Abnormal locomotor muscle recruitment activity is present in horses with shivering and Purkinje cell distal axonopathy.

BACKGROUND: Cerebellar Purkinje cell axonal degeneration has been identified in horses with shivering but its relationship with abnormal hindlimb movement has not been elucidated. OBJECTIVES: To characterise surface electromyographic (sEMG) hindlimb muscle activity in horses with shivering, correlate with clinical scores and examine horses for Purkinje axonal degeneration. STUDY DESIGN: Descriptive controlled clinical study. METHODS: The hindlimb of seven shivering and six control draught horses were clinically scored. Biceps femoris (BF), vastus lateralis (VL), tensor fasciae latae and extensor digitorum longus were recorded via sEMG during forward/backward walking and trotting. Integrated (iEMG) and peak EMG activity were compared between groups and correlated with clinical locomotor exam scores. Sections of the deep cerebellar nuclei (DCN) of six of the seven shivering horses were examined with calbindin immunohistochemistry. RESULTS: In control horses, backward walking resembled forward walking (right hindlimb peak EMG: backward: 47.5 ± 21.9%, forward: 36.9 ± 15.7%) but displayed significantly higher amplitudes during trotting (76.1 ± 3.4%). However, in shivering horses, backward walking was significantly different from forward (backward: 88.5 ± 21.5%, forward: 49.2 ± 8.9%), and resembled activity during trotting (81.4 ± 4.8%). Specific to backward walking, mean sEMG amplitude fell outside two standard deviations of mean control sEMG for ≥25% of the stride in the BF for all seven and the VL for six of the seven shivering horses. Locomotor exam scores were correlated with peak EMG (r = 0.87) and iEMG (r = 0.87). Calbindin-positive spheroids were present in Purkinje axons in DCN of all shivering horses examined. MAIN LIMITATIONS: The neuropathological examination focused specifically on the DCN and, therefore, we cannot fully exclude additional lesions that may have influenced abnormal sEMG findings in shivering horses. CONCLUSION: Shivering is characterised by abnormally elevated muscle recruitment particularly in BF and VL muscles during backward walking and associated with selective Purkinje cell distal axonal degeneration.

Cerebellar Abiotrophy Across Domestic Species.

Cerebellar abiotrophy (CA) is a neurodegenerative disorder affecting the cerebellum and occurs in multiple species. Although CA is well researched in humans and mice, domestic species such as the dog, cat, sheep, cow, and horse receive little recognition. This may be due to few studies addressing the mechanism of CA in these species. However, valuable information can still be extracted from these cases. A review of the clinicohistologic phenotype of CA in these species and determining the various etiologies of CA may aid in determining conserved and required pathways necessary for proper cerebellar development and function. This review outlines research approaches of studies of CA in domestic species, compared to the approaches used in mice, with the objective of comparing CA in domestic species while identifying areas for further research efforts.

Variation in MUTYH expression in Arabian horses with Cerebellar Abiotrophy.

Cerebellar Abiotrophy (CA) is a neurodegenerative disease in Arabian horses affecting the cerebellum, more specifically the Purkinje neurons. Although CA occurs in several domestic species, CA in Arabian horses is unique in that a single nucleotide polymorphism (SNP) has been associated with the disease. Total RNA sequencing (RNA-seq) was performed on CA-affected horses to address the molecular mechanism underlying the disease. This research expands upon the RNA-seq work by measuring the impact of the CA-associated SNP on the candidate gene MutY homolog (MUTYH) and its regulation, isoform-specific expression and protein localization. We hypothesized that the CA-associated SNP compromises the promoter region of MUTYH, leading to differential expression of its isoforms. Our research demonstrates that the CA-associated SNP introduces a new binding site for a novel transcription factor (Myelin Transcription Factor-1 Like protein, MYT1L). In addition, CA-affected horses show differential expression of a specific isoform of MUTYH as well as different localization in the Purkinje and granular neurons of the cerebellum.

Abiotrofia cerebelar em um gato: relato de caso / Cerebellar abiotrophy in a feline: case report

Um caso de abiotrofia cerebelar em um gato com 45 dias de idade foi diagnosticado no Laboratório de Patologia Animal, Hospital Veterinário da Universidade Federal de Campina Grande. O animal apresentava, havia 15 dias, apatia, anorexia, desidratação, ataxia, hipermetria, espasticidade dos membros torácicos e pélvicos, tremores de intenção, nistagmo, opistótono, déficit proprioceptivo e ausência de resposta de ameaça. Clinicamente, havia a suspeita de hipoplasia cerebelar, e, devido ao prognóstico desfavorável, o animal foi eutanasiado. Na necropsia, não foram observadas alterações macroscópicas. Microscopicamente, as lesões estavam restritas ao cerebelo e caracterizavam-se por alterações neurodegenerativas e necróticas, com desaparecimento segmentar dos neurônios de Purkinje. Nessas áreas, também se verificaram espaços em branco, denominado aspecto de cesto vazio, resultantes da perda dos neurônios de Purkinje, além de raros esferoides axonais e proliferação dos astrócitos de Bergmann. Em algumas áreas, a camada granular estava hipocelular e havia moderada gliose multifocal na camada molecular. O diagnóstico de abiotrofia cerebelar foi realizado com base nos dados epidemiológicos, clínicos e, principalmente, pelas alterações histopatológicas dos neurônios de Purkinje características da doença.(AU)

The aim of this report was to describe a case of cerebellar abiotrophy in cat with 45-year-old diagnosed at the Animal Pathology Laboratory, Veterinary Hospital of the Federal University of Campina Grande. The animal had presented 15-day apathy, anorexia, dehydration and neurological signs, characterized by ataxia, hypermetria, spasticity of fore and hindlimbs, intention tremor, nystagmus, opisthotonos, proprioceptive deficits, and absence of threat response. Clinically, cerebellar hypoplasia was suspected and the animal was euthanized due to poor prognosis. During necropsy, gross lesions were not observed. Microscopically the lesions were restricted to the cerebellum and were characterized by neurodegenerative and necrotic damage with segmental disappearance of the Purkinje cells. In these areas, there were also empty spaces, called the empty basket aspect, resulting from the loss of Purkinje cells, as well as rare axonal spheroids and proliferation of Bergmann's astrocytes. In some areas, the granular layer was hypocellular and there was moderate multifocal gliosis in the molecular layer. The diagnosis of cerebellar abiotrophy was based on epidemiological, clinical and mainly on histopathological changes in neurons of Purkinje disease characteristics.(AU)

Cerebellar Disease of Ruminants.

Cerebellar disease can be congenital or acquired. Clinical signs of cerebellar disease include hypermetric gait in all limbs, normal to increased muscle tone, wide-based stance, swaying, intention tremor, and convulsions. Vestibular signs may be observed. Differential diagnoses for etiology include congenital (hypoplasia, abiotrophy, and lysosomal storage diseases), viral, bacterial, and toxic plants. Animals may present aborted as fetuses or stillborn, be affected at birth, develop disease at a few months old, or acquire the disease later in life.

Genome sequencing reveals a splice donor site mutation in the SNX14 gene associated with a novel cerebellar cortical degeneration in the Hungarian Vizsla dog breed.

BACKGROUND: Cerebellar cortical degeneration (CCD) is an increasingly recognised neurodegenerative disease process affecting many dog breeds. Typical presentation consists of a progressive cerebellar ataxia, with a variable age at onset and rate of progression between different breeds. Cerebellar histopathological findings typically consist of primary Purkinje neuronal degeneration and loss, with variable secondary depletion of the granular and molecular cell layers. Causative genes have been identified associated with CCD in several breeds, allowing screening for selective breeding to reduce the prevalence of these conditions. There have been no previous reports of CCD in Hungarian Vizslas. RESULTS: Two full-sibling Hungarian Vizsla puppies from a litter of nine presented with a history of progressive ataxia, starting around three months of age. Clinical signs included marked hypermetric and dysmetric ataxia, truncal sway, intention tremors and absent menace responses, with positional horizontal nystagmus in one dog. Routine diagnostic investigations were unremarkable, and magnetic resonance imaging performed in one dog revealed mild craniodorsal cerebellar sulci widening, supportive of cerebellar atrophy. Owners of both dogs elected for euthanasia shortly after the onset of signs. Histopathological examination revealed primary Purkinje neuron loss consistent with CCD. Whole genome sequencing was used to successfully identify a disease-associated splice donor site variant in the sorting nexin 14 gene (SNX14) as a strong causative candidate. An altered SNX14 splicing pattern for a CCD case was demonstrated by RNA analysis, and no SNX14 protein could be detected in CCD case cerebellum by western blotting. SNX14 is involved in maintaining normal neuronal excitability and synaptic transmission, and a mutation has recently been found to cause autosomal recessive cerebellar ataxia and intellectual disability syndrome in humans. Genetic screening of 133 unaffected Hungarian Vizslas revealed the presence of three heterozygotes, supporting the presence of carriers in the wider population. CONCLUSIONS: This is the first report of CCD in Hungarian Vizsla dogs and identifies a highly associated splice donor site mutation in SNX14, with an autosomal recessive mode of inheritance suspected.

PROGRESSIVE SYRINGOHYDROMYELIA AND DEGENERATIVE AXONOPATHY IN A BOBCAT (LYNX RUFUS) FOLLOWING SURGICAL CORRECTION OF A CHIARI-LIKE MALFORMATION.

A 3-yr-old male captive bobcat (Lynx rufus) presented with chronic ataxia and right-sided head tilt. Magnetic resonance imaging (MRI) revealed cerebellar crowding and compression consistent with Chiari-like malformation. The clinical signs did not improve after surgical occipital craniectomy, and 2 mo postoperatively a second MRI showed hydromyelia and continued cerebellar compression. The bobcat was euthanized, and necropsy showed chronic focal cerebellar herniation and chronic multifocal atlanto-occipital joint osteophyte proliferation. Histology confirmed the presence of a thick fibrous membrane along the caudal aspect of the cerebellar vermis, suggestive of postoperative adhesions, and axonal degeneration of the cervical spinal cord, even in sections without a central canal lesion. These lesions appear to have been complications associated with surgical correction of the Chiari-like malformation.

A novel pathogenic mechanism for cerebellar lesions produced by Solanum bonariense in cattle.

Intoxication with Solanum bonariense in cattle causes cerebellar cortical degeneration with perikaryal vacuolation, axonal swelling, and death primarily of Purkinje cells, with accumulation of electron-dense residual storage bodies in membrane-bound vesicles. The pathogenesis of this disease is not fully understood. Previously, we proposed that inhibition of protein synthesis in Purkinje cells among other altered metabolic pathways could lead to cytoskeletal alterations, subsequently altering cell-specific axonal transport. In the present study, immunohistochemical and histochemical methods were used to identify neuronal cytoskeletal alterations and axonal loss, demyelination, and astrogliosis in the cerebellum of intoxicated bovines. Samples of cerebellum from 3 natural and 4 experimental cases and 2 control bovines were studied. Immunoreactivity against neurofilament (NF)-200KDa confirmed marked loss of Purkinje neurons, and phospho-NF protein, ß-tubulin, and affinity reaction against phalloidin revealed an altered perikaryal distribution of neuronal cytoskeletal proteins in the remaining Purkinje cells in intoxicated cattle. Reactive astrogliosis in every layer of the cerebellar cortex was also observed with anti-glial fibrillary acidic protein immunohistochemistry. In affected cattle, demyelination and axonal loss in the cerebellar white matter, as well as basket cell loss were demonstrated with Klüver-Barrera and Bielschowsky stains, respectively. Based on these results, we propose that neuronal cytoskeletal alterations with subsequent interference of the axonal transport in Purkinje cells may play a relevant role in the pathogenesis of this neurodegenerative disorder, and also that demyelination and axonal loss in the cerebellar white matter, as well as astrogliosis in the gray matter, likely occur secondarily to Purkinje cell degeneration and death.

Spontaneous poisoning by Solanum subinerme Jack as a cause of cerebellar cortical degeneration in cattle.

The present work reports cerebellar degeneration in cattle associated with the ingestion of Solanum subinerme in northern Brazil. The main clinical signs were periodic crises with loss of balance, falls, opisthotonus, and nystagmus. The histological lesions consisted of diffuse vacuolation of the perikaryon of the Purkinje neurons, followed by the loss of these cells and their substitution by Bergman glia. It is concluded that S. subinerme is another species of Solanum that causes cerebellar degeneration in cattle.

Congenital cerebellar dysplasia in White Leghorn chickens (Gallus gallus domesticus).

Congenital cerebellar anomalies have been rarely reported in birds. We examined cerebellums with disorganized folia from seven specific-pathogen-free White Leghorn chickens (Gallus gallus domesticus). Islands of heterotopic cortex were distributed from the deeper cortices to the medulla in the cerebellum. The characteristic lesions were composed of randomly admixed components of the cerebellar cortex, including Purkinje cells, a molecular layer and granular cells. Immunofluorescent analysis revealed Purkinje cells with haphazardly extended dendrites and a lack of Bergmann's glial fibres in the foci. Chicken parvovirus, Aino virus and avian retrovirus were not detected in the affected birds by polymerase chain reaction. This is the first report of cerebellar dysplasia in chickens possibly caused by a genetic abnormality.