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Introduction: Idiopathic epilepsy (IE) is a common chronic neurological disorder in dogs. Breed specific knowledge on semiology, age of onset (AoO), seizure frequency, response to treatment, and Quality of Life (QoL) scores for both dog and owner are important. The Labradoodle is originally a cross between the Labrador Retriever and Standard Poodle. The aim of this study was to describe in detail the epilepsy, that is recognized in this designer breed. Method: An online survey was distributed through several platforms to owners of Labradoodles. Only Labradoodles, either registered as such or bred as a Labradoodle were included. To classify the Labradoodles in a TIER level of confidence the criteria of the International Veterinary Task Force were used. Results: Forty labradoodles were included. Thirty-three Labradoodles were classified as IE or suspected IE cases and appeared to have an AoO of 2.3 ± 1.3 years, and a seizure frequency of 5.4 ± 6.5 seizures/year (range 0--25). Seven dogs were classified as EUC, two dogs started before 6 months of age, and five dogs had their first seizures at 8.4 ± 1.2 years of age. The seizure frequency for all EUC dogs was 5.0 ± 3.0 seizures/year (range 0--11). Stress, for both the (suspected) IE and EUC cases, was the most frequently reported seizure precipitating factor (95% of the dogs). AoO and seizure frequency did not seem to be influenced by type of housing, type of owner, or the dog's character as interpreted by the owner. Cluster seizures (CS) were seen in 33% and status epilepticus (SE) in 10% of the included Labradoodles. Many dogs did not need treatment (38%) or only one anti-seizure medication (43%), in which case they tended to respond favorably to treatment. QoL scores were high for both dog (8.3 ± 1.8) and owner (7.3 ± 2.2). Discussion: Compared to the progenitor breeds, epilepsy of Labradoodles is phenotypically like that of the Standard Poodle, except for the existence CS and SE in the Labradoodle. The epilepsy seen in this designer breed has a favorable outcome compared to several other breeds. [ABSTRACT FROM AUTHOR]

Paroxysmal dyskinesias (PDs) are a group of involuntary, hyperkinetic movement disorders that recur episodically and may last seconds to hours. An important feature of PD is that there is no loss of consciousness during the episode. Using a clinical classification, three main types of PDs have been distinguished in canine PD: (1) paroxysmal kinesigenic dyskinesia (PKD) that commences after (sudden) movements, (2) paroxysmal non-kinesigenic dyskinesia (PNKD) not associated with exercise and can occur at rest, and (3) paroxysmal exertioninduced dyskinesia (PED) associated with fatigue. Canine PDs are diagnosed based on the clinical presentation, history, and phenomenology. For the latter, a video recording of the paroxysmal event is extremely useful. An etiological classification of canine PDs includes genetic (proven and suspected), reactive (drug-induced, toxic, metabolic, and dietary), structural (neoplasia, inflammatory, and other structural causes), and unknown causes. In this review, an overview of all reported canine PDs is provided with emphasis on phenotype, genotype, and, where possible, pathophysiology and treatment for each reported canine PD. [ABSTRACT FROM AUTHOR]

Introduction: Chiari-like malformation (CM) and syringomyelia (SM) are disorders that, in dogs, affect mainly small and toy breeds, including the Pomeranian. These disorders are linked to a great number of (owner-reported) clinical signs (ORCS) suggestive of pain. Aging was associated with an increased risk of having SM in several studies. However, there are only a few longitudinal studies that assess the presence and severity of CM/SM over time in CKCS dogs and progression of SM was linked to progression of clinical signs. The aim of this study was to investigate ORCS, CM/SM classification, and quantitative syrinx parameters in relation to progression of time (age) within individual Pomeranians. Materials and methods: Pomeranians with or without ORCS and with or without diagnoses of CM/SM were included that had undergone two (or more) MRI studies of the craniocervicothoracic region between January 2020 and June 2023. Classification of CM/SM and quantitative syrinx measurements were performed. Absolute values as well as ratios for syrinx height, width, and cross-sectional area were included for analysis. Results: A total of 19 Pomeranians were included in the study, of which 11 were male (58%) and 8 were female (42%). The median age at the time of MRI1 was 26 months (range 7-44 months). The median scan interval was 26 months (range 11-49 months). Eleven dogs (58%) were presented with ORCS at the time of MRI1, whereas the other 8 dogs (42%) had no ORCS at that time. At the time of MRI2, there were 17/19 dogs (89%) with ORCS and 2/19 dogs without ORCS (11%). Dogs were significantly more likely to have ORCS at MRI2 than MRI1 (p = 0. 0411). There was no significant difference between CM/SM classification at the time of MRI1 andMRI2. Significant differences were found betweenMRI1 and MRI2 for syrinx height (based on transverse images) (absolute value and ratio P = 0.0059), syrinx width (absolute value P = 0.1055, ratio P = 0.0039), and syrinx cross sectional area (absolute value P = 0.0195, ratio P = 0.0217). Discussion: There are differences in the presence or absence of ORCS as well as quantitative syrinx measurements in Pomeranians at different ages. This finding supports that longitudinal changes occur in the SM status of Pomeranians. [ABSTRACT FROM AUTHOR]

Introduction: Syringomyelia (SM) is a heritable disorder causing a fluid filled cavity (FFC) in the spinal cord with a reported overall prevalence of 39 to 46% in the Cavalier King Charles Spaniels (CKCS). Breeders started screening their CKCS with MRI in the Netherlands since 2004 and in Denmark since 2015. The goal of this study was to evaluate the effect of MRI-based selection in breeding on the prevalence of SM. Method: MRI scans of 2,125 purebred CKCS were available. SM was defined as having a visible FFC in the spinal cord. The prevalence of SM per year of birth was calculated, and a logistic regression was used to evaluate the affected status of offspring from affected versus unaffected parents and age category of the parent and study the combined effect of parental status and age-category to evaluate the effect on the affected status of the offspring. Results: The mean FFC in affected CKCS was 2.03 ± 1.47 mm and ranged from 0.5 to 9 mm (median of 1.5 mm). An age effect exists as older CKCS, which has a higher frequency of being affected compared with younger CKCS. There was no significant sex predilection for SM in this dataset. The mean prevalence of SM decreased slightly from 38% (2010-2014; 2.8 ± 1.3 years of age (mean ± sd); median 2.6 years) to 27% (2015-2019; 2.4 ± 1.2 years of age; median 2.1 years) in the screened population of CKCS (p = 4.3e-07). Breeding with two affected parents increased the odds ratio with 3.08 for producing affected offspring (95% CI 1.58-6.04) compared with breeding with unaffected parents. Discussion: MRI-based screening and selection against SM led to a minimal decrease in the prevalence of SM in the Dutch and Danish CKCS population. Breeding with dogs with SM significantly increases the risk of affected offspring. As the disorder is progressive with age, and based on the results of this study, MRI-based screening for all CKCS is recommended at an age of 3 years or older, and to reduce SM more effectively, CKCS affected with SM should not be used for breeding. [ABSTRACT FROM AUTHOR]

Introduction: Hereditary necrotizing myelopathy (HNM) in young Kooiker dogs is characterized by progressive ataxia and paralysis with autosomal recessive inheritance. The basic genetic defect is unknown. We investigated the possible cause by a genome-wide analysis using six affected and 17 unrelated unaffected Kooiker dogs and by functional follow-up studies. Method: The HNM locus was mapped by a case--control study using a dense SNP array and confirmed by linkage analysis of two pedigrees. The gene exons in the critical region were analyzed by next-generation sequencing. The functional effect of the candidate canine IBA57 pathogenic variant was biochemically examined in an established HeLa cell culture model in which the endogenous IBA75 gene product was depleted by RNAi. Results: The basic defect was localized in the centromeric 5 Mb region of canine chromosome 14. The most associated SNP co-segregated fully with HNM and reached an LOD score of 6.1. A candidate pathogenic mutation was found in the iron--sulfur cluster assembly gene IBA57 and led to the amino acid substitution R147W. The expression of human IBA57 harboring the canine R147W exchange could only partially restore the biochemical defects of several mitochondrial [4Fe-4S] proteins upon IBA57 depletion, showing that the mutant protein is functionally impaired. Discussion: Pathogenic variants in human IBA57 cause multiple mitochondrial dysfunction syndrome 3 (MMDS3), a neurodegenerative disorder with distant similarities to HNM. The incomplete functional complementation of IBA57- depleted human cells by IBA57-R147W identifies the DNA mutation in affected Kooiker dogs as the genetic cause of HNM. Our findings further expand the phenotypic spectrum of pathogenic IBA57 variants. [ABSTRACT FROM AUTHOR]