Abstract
Purpose:
Purebred dogs suffer from several hereditary vision disorders, which resembles corresponding disorders in human patients. Our study has focused on the genetics of retinal dysplasia and vitreous degeneration in two different dog breeds, American Cocker Spaniel and Italian Greyhound, respectively. Both disorders are known to be inherited in the studied breeds, but the genetic background has remained unknown. Both disorders may cause vision deterioration and secondary complications may include glaucoma, lens luxation and retinal detachment, which in turn may lead to a complete loss of vision.
Methods:
We have established a large sample cohort for multifocal retinal dysplasia (MRD) in American Cocker Spaniel (ACS) and for vitreous degeneration (VD) in the Italian Greyhound (IT). A genome-wide association study (GWAS) was performed using canine specific SNP array to map the associated loci in both disorders.
Results:
The GWAS data identified a genome-widely significant association for MRD in ACS on canine chromosome 22 (CFA22) with praw=1.9*10-5, pgenome=0.01 and a tentative association, with a 2 Mb homozygous haplotype, for VD in IT on CFA15 with praw=5.1x10-5, pgenome=0.27. Further replication studies are being performed to confirm and to define the critical associated regions.
Conclusions:
We have mapped two novel loci for two separate canine vision disorders. Ongoing candidate gene sequencing is likely to open new insights to the molecular background of the studied conditions. The identification of genes behind these disorders will establish a large animal model for the corresponding human disorders and the associated genes can be studied in human patients with similar phenotypes. While the associated genes will become candidates for human studies, a genetic test can be offered for the studied breeds.
Keywords: 534 gene mapping •
688 retina •
763 vitreous