Project description:BackgroundNeonatal cerebellar cortical degeneration is a neurodegenerative disease described in several canine breeds including the Beagle. Affected Beagles are unable to ambulate normally from the onset of walking and the main pathological findings include Purkinje cell loss with swollen dendritic processes. Previous reports suggest an autosomal recessive mode of inheritance. The development of massively parallel sequencing techniques has presented the opportunity to investigate individual clinical cases using genome-wide sequencing approaches. We used genome-wide mRNA sequencing (mRNA-seq) of cerebellum tissue from a single Beagle with neonatal cerebellar cortical degeneration as a method of candidate gene sequencing, with the aim of identifying the causal mutation.ResultsA four-week old Beagle dog presented with progressive signs of cerebellar ataxia and the owner elected euthanasia. Histopathology revealed findings consistent with cerebellar cortical degeneration. Genome-wide mRNA sequencing (mRNA-seq) of RNA from cerebellum tissue was used as a method of candidate gene sequencing. After analysis of the canine orthologues of human spinocerebellar ataxia associated genes, we identified a homozygous 8 bp deletion in the β-III spectrin gene, SPTBN2, associated with spinocerebellar type 5 in humans. Genotype analysis of the sire, dam, ten clinically unaffected siblings, and an affected sibling from a previous litter, showed the mutation to fully segregate with the disorder. Previous studies have shown that β-III spectrin is critical for Purkinje cell development, and the absence of this protein can lead to cell damage through excitotoxicity, consistent with the observed Purkinje cell loss, degeneration of dendritic processes and associated neurological dysfunction in this Beagle.ConclusionsAn 8 bp deletion in the SPTBN2 gene encoding β-III spectrin is associated with neonatal cerebellar cortical degeneration in Beagle dogs. This study shows that mRNA-seq is a feasible method of screening candidate genes for mutations associated with rare diseases when a suitable tissue resource is available.
Project description:To identify miRNAs associated with retinal development and degeneration in dogs affected with xlpra2, an early-onset canine retinal degeneration caused by a microdeletion in RPGRORF15. XLPRA2-mutant and normal retinas were selected at different ages for RNA extraction and hybridization on Affymetrix miRNA-specific microarrays.
Project description:Progressive retinal atrophy (PRA) is a common cause of blindness in many pure and mixed breed dogs (Canis lupus familiaris). The typical onset of PRA begins with gradual night vision loss followed by day vision loss due to the death of rod and cone receptors, respectively. There are currently no mutations or genes reported to be causative or associated with PRA in the Hungarian Puli. In this study, we use an extensive list of 53 known PRA genes to screen for putative causal variants in this breed of dog.
Project description:Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) is caused by mutations in SACS gene encoding sacsin. ARSACS patients and mouse models display early degeneration of cerebellum in agreement with high sacsin expression in this organ. We performed unbiased transcriptomic of cerebella from Sacs KO mice versus controls to dissect the mechanisms underlying cerebellar degeneration in ARSACS.
Project description:Australian working Kelpie dogs are known to be affected with an autosomal recessive form of inherited cerebellar ataxia (cerebellar abiotrophy, CA) that is characterised by a degeneration of Purkinje and granule cells in the cerebellar cortex. The clinical signs of CA include cerebellar ataxia, head tremor, motor in-coordination, wide based stance and high stepping gait, with varied clinical onset age. The clinical and pathological features are similar to cerebellar ataxias in humans. The genome-wide association study on a group of working Kelpies affected with the later onset form of CA identified a region on chromosome 9 to be strongly associated with the disease phenotype. Homozygosity analysis and whole genome sequencing identified a missense single nucleotide polymorphism, that segregated with the CA phenotype.
Project description:Dogs frequently develop glaucoma, a disease that leads to vision loss due to loss of retinal ganglion cells and degeneration of axons within the optic nerve. We used Affymetrix Gene chips to characterize transcriptional changes between healthy and glaucomatous retinas. These data describe gene expression changes in the canine retina with glaucoma. RNA was isolated from the retinas of 5 dogs with advanced glaucoma and from 5 normal individuals.