Multi-disease and colour panel aimed at the French Water Dog (Barbet) that groups the prcd progressive retinal atrophy test (prcd-PRA), von Willebrand disease type 1 (vWD1) and the D-locus d1 (dilution) and K-locus colour tests. The panel reports the clear/carrier/affected status for prcd-PRA and vWD1 and the colour genotype for D and K. Molecular testing does not replace ocular examination or haematological monitoring. The applicable breed is the French Water Dog (Barbet): vWD1 due to VWF c.7437G>A is documented in this breed, whereas no documentation exists in the Irish Water Spaniel.

Applicable breed: French Water Dog (Barbet). vWD1 due to VWF c.7437G>A is documented in the Barbet (Donner et al., 2016) and recorded in OMIA:001057-9615; in the Irish Water Spaniel there is no documentation of vWD1 or of prcd-PRA. There are no large population frequency estimates for the Barbet (limited data). prcd-PRA has no published breed-specific validation in the Barbet, although the variant is widespread in many breeds.

- Reduced night vision and progressive retinal atrophy (prcd-PRA)\n- Mild mucocutaneous bleeding or prolonged bleeding after surgery/trauma (vWD1)\n- Diluted coat (blue/fawn) in dd homozygotes (D-locus d1)\n- Colour pattern determined by K-locus (KB dominant over yellow/ky)

prcd-PRA was associated with the PRCD gene and its molecular test became widespread in multiple breeds (Zangerl et al., 2006). vWD type 1 is associated with the VWF c.7437G>A variant, described in the Doberman and in more than a dozen breeds; Donner et al. (2016) documented carriers in the Barbet and OMIA lists the breed among those affected (OMIA:001057-9615). The classic D-locus (dilution) was associated with the MLPH gene (Drögemüller et al., 2007), with additional alleles d2 and d3 described later (Bauer et al., 2018; Van Buren et al., 2020). The K-locus (dominant black) was associated with CBD103 (Candille et al., 2007).

- Genotype breeding animals before mating\n- For prcd-PRA (recessive): do not mate carrier × carrier (25% risk of affected homozygotes); carrier × clear produces 0% affected and 50% carriers\n- For vWD1 (VWF c.7437G>A; dominant expression with incomplete penetrance): a carrier can transmit the variant to ~50% of the offspring; consider mating with a clear animal and confirming the von Willebrand factor level\n- For D-locus and K-locus: useful information to predict coat colours; carries no disease risk\n- Before surgery in animals not genotyped for vWD1, assess the bleeding time\n- After a confirmed clinical case, do not repeat the parental mating and communicate the status to the buyer

The applicable breed of the panel is the French Water Dog (Barbet), not the Irish Water Spaniel: vWD1 due to VWF c.7437G>A is documented in the Barbet (Donner et al., 2016; OMIA:001057-9615) and is not recorded in the Irish Water Spaniel. Annual ocular examination (ECVO) complementary. vWD1 is confirmed by VWF antigen and activity measurement; assess the bleeding time before surgery. The colour tests (D-locus and K-locus) are informative, not diagnostic of disease. prcd-PRA has no published breed-specific validation in the Barbet, although the variant is widespread in many breeds.

1. Zangerl B, et al. Genomics. 2006. PMID: 16938425.
2. Donner J, et al. Genetic panel screening of nearly 100 mutations reveals new insights into the breed distribution of risk variants for canine hereditary disorders. PLoS One. 2016. PMID: 27525650.
3. Drögemüller C, et al. A noncoding melanophilin gene (MLPH) SNP at the splice donor of exon 1 represents a candidate causal mutation for coat color dilution in dogs. J Hered. 2007. PMID: 17519392.
4. Bauer A, et al. A novel MLPH variant in dogs with coat colour dilution. Anim Genet. 2018. PMID: 29349785.
5. Van Buren SL, et al. A third MLPH variant causing coat color dilution in dogs. Genes (Basel). 2020. PMID: 32531980.
6. Candille SI, et al. A beta-defensin mutation causes black coat color in domestic dogs. Science. 2007. PMID: 17947548.
OMIA:001057-9615 (vWD1); OMIA:000031-9615 (D-locus/MLPH); OMIA:001416-9615 (K-locus/CBD103).