Heritability of lenticular myopia in English Springer spaniels

• Published in: Investigative ophthalmology & visual science Vol. 54; no. 12; p. 7324
• Main Authors: Kubai, Melissa A, Labelle, Amber L, Hamor, Ralph E, Mutti, Donald O, Famula, Thomas R, Murphy, Christopher J
• Format: Journal Article
• Language: English
• Published: United States 08.11.2013
• Subjects: Animals; Dog Diseases - genetics; Dogs; Markov Chains; Myopia - genetics; Myopia - veterinary; Pedigree; Phenotype; Quantitative Trait, Heritable; Refractive Errors - genetics; Refractive Errors - veterinary; Species Specificity; refractive error; lenticular myopia; English Springer spaniel; heritability
• ISSN: 1552-5783; 1552-5783
• DOI: 10.1167/iovs.12-10993

We determined whether naturally-occurring lenticular myopia in English Springer spaniels (ESS) has a genetic component. Streak retinoscopy was performed on 226 related ESS 30 minutes after the onset of pharmacologic mydriasis and cycloplegia. A pedigree was constructed to determine relationships between affected offspring and parents. Estimation of heritability was done in a Bayesian analysis (facilitated by the MCMCglmm package of R) of refractive error in a model, including terms for sex and coat color. Myopia was defined as ≤-0.5 diopters (D) spherical equivalent. The median refractive error for ESS was 0.25 D (range, -3.5 to +4.5 D). Median age was 0.2 years (range, 0.1-15 years). The prevalence of myopia in related ESS was 19% (42/226). The ESS had a strong correlation (r = 0.95) for refractive error between the two eyes. Moderate heritability was present for refractive error with a mean value of 0.29 (95% highest probability density, 0.07-0.50). The distribution of refractive error, and subsequently lenticular myopia, has a moderate genetic component in ESS. Further investigation of genes responsible for regulation of the development of refractive ocular components in canines is warranted.