A genome-wide association study to investigate genetic loci associated with primary glaucoma in American Cocker Spaniels

OBJECTIVE To identify genetic associations with primary glaucoma (PG) in American Cocker Spaniels using a genome-wide association study (GWAS). ANIMALS A nationwide ambidirectional case-control cohort study was performed in American Cocker Spaniels that had an ophthalmic examination performed by a veterinarian. Ninety-four dogs with PG (cases) and 111 dogs without glaucoma (controls) met phenotypic criteria and had a blood sample collected after receiving informed owner consent. PROCEDURES Genomic DNA was extracted from whole blood samples and genotyped (CanineHD BeadChip, Illumina Inc). A case-control GWAS using a linear mixed model was performed, and 3 significance thresholds were calculated (1) using a Bonferroni correction on all single nucleotide polymorphisms (SNPs) included in the GWAS, (2) using a Bonferroni correction on only the unlinked SNPs from a pruned data set, and (3) using 10,000 random phenotype permutations. RESULTS Following genotype data quality control, 89 cases and 93 controls were included in the GWAS. We identified an association on canine chromosome (CFA10); however, it did not reach statistical significance. Potential candidate genes within the surrounding linkage disequilibrium interval include coiled-coil domain containing 85A (CCDC85A) and extracellular growth factor containing fibulin extracellular matrix protein 1 (EFEMP1).

Automated summary

This study aimed to identify genetic associations with primary glaucoma in American Cocker Spaniels using a GWAS. Although an association on canine chromosome CFA10 was identified, it did not reach statistical significance. Potential candidate genes within the surrounding linkage disequilibrium interval include CCDC85A and EFEMP1.