OMIA 002275-9615 : Coat colour, cocoa in Canis lupus familiaris
The HPS3 gene encodes a subunit of a protein complex named "Biogenesis of Lysosome-related Organelles Complex-2 (BLOC-2)". This protein complex controls the sorting and transport of newly synthesized integral membrane proteins from early endosomes to both lysosomes and lysosome-related organelles, such as melanosomes and platelet-dense granules. Loss of function variants in HPS3 therefore may result in a syndromic phenotype that was initially recognized in humans with Hermansky-Pudlak syndrome 3. This phenotype is characterized by pigment dilution, mildly reduced visual acuity and a mild bleeding disorder due to the absence of platelet-dense bodies.
"Based on the comprehensive knowledge on HPS3 function together with the observed genotype–phenotype association" Kiener et al. 2020 concluded that "HPS3:c.2420G>A is very likely the causative genetic variant for the brown coat color in the investigated French Bulldogs".Clinical features: HPS3 deficient (cocoa) coloured dogs are born brown. Their colour darkens with age and they become slightly darker than TYRP1-deficient (chocolate) dogs as adults (Kiener et al. 2020). So far, it has not been investigated whether cocoa coloured dogs have any bleeding disorder or visual impairments, similar to what has been observed in human patients with Hermansky-Pudlak syndrome 3. Breed: French Bulldog. Associated gene:
|Symbol||Description||Species||Chr||Location||OMIA gene details page||Other Links|
|HPS3||Hermansky-Pudlak syndrome 3||Canis lupus familiaris||23||NC_051827.1 (44566353..44606057)||HPS3||Homologene, Ensembl, NCBI gene|
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WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.
|Breed(s)||Variant Phenotype||Gene||Allele||Type of Variant||Reference Sequence||Chr.||g. or m.||c. or n.||p.||Verbal Description||EVA ID||Year Published||PubMed ID(s)||Acknowledgements|
|French Bulldog||Cocoa||HPS3||HPS3^co||nonsense (stop-gain)||CanFam3.1||23||g43969695G>A||c.2420G>A||p.(Trp807*)||XM_542830.6:c.2420G>A; XP_542830.3:p.(Trp807*)||2020||32526956|
|2020||Kiener, S., Kehl, A., Loechel, R., Langbein-Detsch, I., Müller, E., Bannasch, D., Jagannathan, V., Leeb, T. :|
|Novel Brown Coat Color (Cocoa) in French Bulldogs Results from a Nonsense Variant in <i>HPS3</i>. Genes (Basel) 11:, 2020. Pubmed reference: 32526956. DOI: 10.3390/genes11060636.|
- Created by Frank Nicholas on 14 Jun 2020
- Changed by Frank Nicholas on 14 Jun 2020
- Changed by Tosso Leeb on 16 Jun 2020
- Changed by Tosso Leeb on 17 Jun 2020