Test Detail
Bobtail pack: hereditary ataxia (HA) + exercise-induced collapse (EIC) + primary ciliary dyskinesia (PCD) + degenerative myelopathy (DM exon 2) + ivermectin sensitivity (MDR1)
General · Dog
Genetic panel of the bobtail (Old English Sheepdog) grouping five hereditary conditions: hereditary ataxia/juvenile cerebellar ataxia (HA, Purkinje cell degeneration), exercise-induced collapse (EIC, paralysis after intense exertion), primary ciliary dyskinesia (PCD, defect of respiratory cilia with recurrent bronchopneumonias and situs inversus), degenerative myelopathy (DM, SOD1 exon 2 variant) and sensitivity to ivermectin and other drugs (MDR1, defect of the P-glycoprotein of the blood-brain barrier).
Incidence
Bobtail (Old English Sheepdog). PCD due to CCDC39 has an estimated carrier frequency of ~19% in European bobtails and ~7% in North American ones. MDR1 is present in the bobtail and other herding breeds. For HA and EIC the population frequencies are not reliably published (limited data). DM exon 2 has no published cases in the breed (included as a precaution). EIC/DNM1: validated in Bobtail by the discovering lab and testable via OFA; without a KC scheme or breed-specific publication.
Breeder management
- Genotype breeding dogs for RAB24, CCDC39, SOD1 exon 2 and ABCB1 before mating\n- Do not cross two carriers for the same variant\n- A carrier may be crossed with a clear animal and the offspring intended for breeding must be tested\n- After a confirmed case, do not repeat the parental cross and communicate the status to the buyer\n- For homozygous MDR1: avoid ivermectin, moxidectin, loperamide and other P-gp substrate drugs; warn the veterinarian\n- For PCD: intensive respiratory monitoring in puppies and consider radiographic screening for situs in suspected animals
Specialist notes
HA of the bobtail must be distinguished from other cerebellar ataxias (storage, degenerative, toxic). PCD can be confused with recurrent bacterial bronchitis or feline/canine asthma; the definitive diagnosis combines ciliary biopsy with electron microscopy and genetic test. MDR1 must be borne in mind when prescribing in bobtails, since standard doses of ivermectin can be neurotoxic in homozygotes.
References
1. Agler C et al. (2014) Canine hereditary ataxia in Old English Sheepdogs and Gordon Setters is associated with a defect in the autophagy gene encoding RAB24. PLoS Genet 10:e1003991. PMID: 24516392
2. Merveille AC et al. (2014) Clinical findings and prevalence of the mutation associated with primary ciliary dyskinesia in Old English Sheepdogs. J Vet Intern Med 28:771-8. PMID: 24773602
3. Patterson EE et al. 2008, mutación de DNM1 asociada al colapso inducido por el ejercicio (PMID 18806795)
4. Minor KM et al. 2011, DNM1 en Labrador y otras razas (PMID 21782486)
5. OFA: EIC/DNM1, Old English Sheepdog entre las razas con test registrado (criterio de inclusión: demanda de criadores del club USA; sin esquema UK KC)
2. Merveille AC et al. (2014) Clinical findings and prevalence of the mutation associated with primary ciliary dyskinesia in Old English Sheepdogs. J Vet Intern Med 28:771-8. PMID: 24773602
3. Patterson EE et al. 2008, mutación de DNM1 asociada al colapso inducido por el ejercicio (PMID 18806795)
4. Minor KM et al. 2011, DNM1 en Labrador y otras razas (PMID 21782486)
5. OFA: EIC/DNM1, Old English Sheepdog entre las razas con test registrado (criterio de inclusión: demanda de criadores del club USA; sin esquema UK KC)