Test Detail

Multi-disease panel directed at the Spanish Water Dog that groups seven tests for hereditary conditions described in the breed: two forms of progressive retinal atrophy (prcd-PRA and eo-PRA), brachyuria (natural short tail), neuroaxonal dystrophy (NAD), congenital hypothyroidism with goitre (CHG), degenerative myelopathy (DM exon 2) and hyperuricosuria (HUU). The panel allows ocular, neurological, endocrine and urological conditions to be managed in a single sample. Several conditions have variable penetrance or are late-onset, so the molecular test is only one part of reproductive management.

Applicable breed: Spanish Water Dog. Carrier frequencies are not published systematically for the seven variants (limited data); prcd-PRA and HUU are documented in the breed, whereas eo-PRA, NAD and CHG have scarcer case numbers and must be verified in the specific literature.

- Reduced night vision and progressive retinal atrophy (prcd-PRA, eo-PRA)\n- Natural short tail or partial absence (brachyuria)\n- Signs of neuroaxonal dystrophy: ataxia, progressive weakness, proprioceptive deficits (NAD)\n- Lethargy, stunted growth, goitre and signs of congenital hypothyroidism (CHG)\n- Progressive limb paresis with proprioceptive ataxia (DM)\n- Urolithiasis due to cystine stones (HUU)

The panel tests were developed independently. prcd-PRA was associated with the PRCD gene. Natural brachyuria was linked to the T gene (Brachyury). HUU was associated with SLC2A9. Canine DM was associated with the exon 2 variant of SOD1 from the work of Awano and colleagues in 2009. eo-PRA of the Spanish Water Dog is associated with a PDE6B deletion (2020); NAD (TECPR2) and CHG (TPO) are documented in the breed with limited case numbers.

- Genotype breeding animals before mating\n- For the recessive conditions (prcd-PRA, eo-PRA, NAD, CHG, DM, HUU): do not mate carrier×carrier (25% risk of affected homozygotes); carrier×clear produces 0% affected and 50% carriers\n- For brachyuria (T): do not mate two heterozygous animals with a natural short tail because of the risk of non-viable homozygotes; know the genotype before deciding on a short tail\n- After a confirmed clinical case, do not repeat the parental mating and communicate the status to the buyer

Complementary annual ocular examination (ECVO); differentiate prcd-PRA (late) from eo-PRA (early) by age of onset and electroretinography. CHG is confirmed by hormone profile (T4, TSH) and early replacement management. NAD requires neurological study and exclusion of other causes. HUU is confirmed by urinalysis (uric acid) and dietary management. DM is a diagnosis of exclusion: rule out spinal cord compression, disc herniation and neoplasia. Differentiate natural brachyuria from amputation.

1. Awano T y cols. 2009, asociación de la variante del exón 2 de SOD1 con la mielopatía degenerativa canina (PNAS)
2. Trabajos sobre PRCD y prcd-PRA canina
3. Trabajos sobre SLC2A9 e hiperuricosuria en el perro
4. AAVO 2020, PDE6B en Perros de Agua españoles con eo-PRA (PMID 32639685); OMIA:002282