Ocular morphologic traits in the American Cocker Spaniel may confer primary angle closure glaucoma susceptibility

Area of Science:

• Ophthalmology
• Veterinary Medicine
• Genetics

Background:

• Acute primary angle closure glaucoma (PACG) is an ophthalmic emergency causing vision loss in humans and dogs.
• Epidemiological similarities exist between human and canine PACG, with older females being more affected.
• American Cocker Spaniels (ACS) exhibit a high prevalence of PACG.

Purpose of the Study:

• To identify genetic risk factors for PACG in American Cocker Spaniels using a genome-wide association study (GWAS).
• To assess intrinsic ocular morphologic traits associated with PACG susceptibility in ACS.

Main Methods:

• A case-control, breed-matched genome-wide association study (GWAS) was conducted.
• Ocular morphologic traits of normal ACS were assessed.

Main Results:

• The GWAS did not identify specific genetic loci associated with PACG in ACS.
• Normal ACS exhibit a crowded anterior ocular segment and narrow iridocorneal angle, consistent with human risk factors.
• Unique ACS features include posterior iris bowing and extended iridolenticular contact, resembling human conditions like reverse pupillary block.

Conclusions:

• Intrinsic ocular morphology, rather than specific genetic loci, appears to be a significant risk factor for PACG in American Cocker Spaniels.
• The anatomical features observed in ACS suggest their potential as a naturally occurring animal model for studying human PACG.