Test Detail

Multidisease panel aimed at the Pembroke Welsh Corgi that groups together four molecular tests for hereditary conditions described in the breed: rcd3-PRA progressive retinal atrophy, brachyuria (natural short tail), von Willebrand disease type 1 (vWD-1) and degenerative myelopathy (DM exon 2). Each test reports the clear/carrier/affected status for the corresponding variant and allows matings to be planned while avoiding diseased animals or those with bleeding risk. The panel does not replace the ocular examination or clinical follow-up: DM has incomplete penetrance and vWD-1 may require hemostatic confirmation.

Applicable breed: Pembroke Welsh Corgi. Carrier frequencies are not published systematically for the four variants (limited data); vWD-1 and DM are documented in the breed, and rcd3-PRA (PDE6A) is documented in the Pembroke in addition to the Cardigan (Donner et al. 2016).

- Reduced night vision and early retinal atrophy (rcd3-PRA)
- Natural short tail or partial absence (brachyuria)
- Post-surgical or post-trauma hemorrhages, ecchymoses and epistaxis (vWD-1)
- Progressive paresis of the thoracic and pelvic limbs with proprioceptive ataxia (DM)

rcd3-PRA was classically associated with a mutation in PDE6A described in the Cardigan Welsh Corgi (Petersen-Jones et al., late 1990s); the PDE6A variant is also documented in the Pembroke (Donner et al. 2016, who list it in Cardigan, Pembroke, Chinese Crested and Pomeranian). Natural brachyuria was linked to the T gene (Brachyury) in short-tailed breeds, including the Pembroke. Canine vWD-1 was associated with the c.743G>A variant of the VWF gene described by several groups in affected breeds. Canine DM was linked to the exon 2 variant of SOD1 from the work of Awano and colleagues in 2009.

- Genotype breeding animals before mating; the panel allows four conditions to be managed in a single sample
- For the recessive conditions (rcd3-PRA, vWD-1, DM): do not mate carrier×carrier (25% risk of affected homozygotes); carrier×clear produces 0% affected and 50% carriers
- For brachyuria (T): do not mate two heterozygous natural short-tailed animals because of the risk of non-viable homozygotes; know the genotype before deciding on a short tail
- After a confirmed clinical case, do not repeat the parental mating and communicate the status to the buyer

Check which specific variants each laboratory includes, because not all offer rcd3-PRA for the Pembroke. Annual ocular examination (ECVO) complementary for conditions not detected by DNA or of late onset. vWD-1 is confirmed with von Willebrand antigen measurement; low values are suggestive but the bleeding phenotype is variable. DM is a diagnosis of exclusion: rule out spinal cord compression, disc herniation and neoplasia before attributing the condition to SOD1. Differentiate natural brachyuria from tail amputation or trauma.

1. Petersen-Jones SM et al. 1999, mutación PDE6A y rcd3-PRA en Corgi Cardigan (PMID 10393029)
2. Donner J et al. 2016, PDE6A en Cardigan, Pembroke, Crestado chino y Pomerania (PMID 27525650)
3. Awano T et al. 2009, SOD1 exón 2 y mielopatía degenerativa (PMID 19188595)
4. Hytönen MK et al. 2009, braquiuria T-box en razas de cola corta (PMID 18854372)
5. OMIA:001057 vWD tipo 1 (incluye Pembroke Welsh Corgi)