Inheritance of cataract in the Bichon Frise

Veterinary Ophthalmology, 2003

Purpose To determine the clinical characteristics of possible inherited cataract in the Bichon Frise breed. These characteristics include the relative frequency, gender effects, site of first cataract formation, age of onset, relationship of age to cataract maturity, and other concurrent pre-and postoperative ophthalmic diseases. Methods Four different populations of Bichon Frise were examined. They included:

2008

PURPOSE. To determine whether the distribution of naturally occurring myopia in Labrador Retrievers has a genetic component. METHODS. Pedigree records of a large canine family were analyzed. Pure Labrador Retrievers, 1 to 8 years of age, free of ocular disease, and available for testing were studied. Refractive error was measured by cycloplegic retinoscopy in both eyes. The family included mating loops, and so an expectation maximization (EM) algorithm (multivar program, MORGAN software; University of Washington, Seattle) was used to calculate log likelihoods of refractive error with environmental and additive genetic models. The fixed effects of coat color, sex, and litter size were also tested. RESULTS. In our sample of 116 dogs from this one family, the average spherical equivalent refraction (SER) was Ϫ0.41 D (range, Ϫ5.38 to ϩ1.65 D, mean of both eyes, n ϭ 116): 31% were myopic (SER Յ Ϫ0.50 D), 60% were emmetropic (SER ϭ Ϫ0.49 to ϩ0.99 D), and 9% were hyperopic (SER Ն ϩ1.00 D). The significance of fixed and genetic effects was tested by comparing the full model (including genetic and all fixed effects) to models with one effect removed. Litter size and additive genetic effects were significant (P ϭ 0.0013 and P ϭ 0.000093, respectively), whereas sex and coat color were not. The overall variance in SER was accounted for approximately equally by additive genetic variance and residual/environmental variance. Narrow sense heritability of SER was 0.506. CONCLUSIONS. The distribution of refractive error within this family of Labrador Retrievers had a significant genetic component, but was also influenced by other factors (litter size, and undefined residual/environmental effects). The dog represents a unique model for the study of naturally occurring, heritable, high-prevalence, low-degree myopia.

Veterinary Ophthalmology, 2004

Objective In this study 2000 dogs were examined ophthalmoscopically to determine presence of cataract. Materials and methods The dogs examined were predominantly from veterinary hospital populations but also from the Waltham Center For Pet Nutrition, rehoming charities and breeding kennels. Prevalence of cataract was thus determined for different age groups (year cohorts). The age at which prevalence of cataract was 50% (C 50 ) was determined indirectly from a fitted prevalence curve.

2013

Progressive retinal atrophies (PRA) are a heterogeneous group of inherited eye diseases common to both dogs and man. Over 100 individual canine breeds display some sort of retinal degeneration, making the dog an extremely valuable resource both for finding the genetic determinants of inherited blindness and for developing naturally occurring animal models that mimic human disease. Progressive retinal atrophies within the English mastiff displayed an ambiguous mode of inheritance. By conducting outcross matings between affected English mastiffs and normal animals from other breeds, the mode of inheritance was confirmed as dominant. This directed candidate gene analysis and led to identification of two synonymous mutations and one nonsynonymous mutation within the canine rhodopsin gene. The nonsynonymous mutation (T4R) is the cause of PRA in the English mastiff, and a test was developed to investigate its presence in 17 additional breeds. Testing of PRA-affected animals from 16 breeds...

Veterinary Ophthalmology, 2016

Objective: To analyze the change in prevalence and incidence of hereditary eye diseases (HED) in dachshunds due to breeding regulations based on biennial examinations performed by the German panel of veterinary ophthalmologists (DOK) from 1998 to 2011. Animals included: A total of 12,242 dachshunds examined by the DOK and pedigree data of 318,852 dachshunds provided by the German Dachshund Club (DTK). Procedures: The prevalence for congenital cataract (CC), distichiasis (DIST), hereditary cataract (HC), persistent pupillary membranes (PPMs), persistent hyperplastic tunica vasculosa lentis / persistent hyperplastic primary vitreous (PHTVL/PHPV), progressive retinal atrophy (PRA), retinal dysplasia (RD) and findings such as fiberglass-like cataract (FGC) and prominent suture lines (PSLs) was analyzed. The significance (P), confidence interval (CI), odds ratio (OR), relative risk (RR) and inbreeding coefficients (F) were calculated and p<0.05 was considered significant. The incidence was evaluated based on affected dogs within birth cohorts from 1993 to 2006. Results: The prevalence of the conditions studied were: CC 0.5%, DIST 6.7%, HC 3.9%, PPMs 8.4%, PHTVL/PHPV 0.4%, PRA 1.5%, RD 0.2%, FGC 2.2% and PSL 1.5%. The incidence of PRA decreased significantly from 6.0% to 0.6% for dogs born from 1993 to 2006, while HC showed a decreasing trend from 8.7% to 3.1%. More males than females were diagnosed with HC and PRA. Dachshunds with HEDs had an F that was not significantly higher than that of healthy dachshunds. Conclusions: The decreasing incidence of PRA and HC in dachshunds supports the use of frequent HED examinations in combination with breeding control.

Investigative Ophthalmology & Visual Science, 2013

PURPOSE. We determined whether naturally-occurring lenticular myopia in English Springer spaniels (ESS) has a genetic component. METHODS. 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 À0.5 diopters (D) spherical equivalent. RESULTS. The median refractive error for ESS was 0.25 D (range, À3.5 to þ4.5 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 ¼ 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). CONCLUSIONS. 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.

Veterinary Medicine: Research and Reports

Dogs are affected by many hereditary diseases just as humans are. One group of these diseases comprises of retinal disorders, which are a growing problem in canine breeding. These disorders are heterogeneous, with diverse causative mutations and modes of inheritance. Some affect only one breed, while others may affect many breeds; some breeds are affected by only one disease, while others can be affected by two or more. Dog breeders should take into account the presence of any deleterious alleles when choosing parents for the next generation.

This paper aims to give an overview on the genetic aspects of PRA in canines through the following topics: (1) fundamentals in genetics; (2) advantages of studies in dogs for both humans and dogs; (3) how to search for genes and mutations involved in hereditary diseases; (4) update on the genes and mutations identified in hereditary retinal diseases; (5) genetic tests: definitions of a mutation genetic test and a linkage genetic test; quality of a genetic test: the methods used, the number of dogs and the populations analyzed within a breed; (6) update on available genetic tests; (7) the role of the veterinary ophthalmologist in fundamental genetic research: example of an X-linked PRA in the Border Collie; (8) the place of genetic tests in ophthalmology for the practitioner.

BMC Veterinary Research, 2020

Background This paper reports the significant prevalence of a presumed hereditary cataract in the Bengal cat breed in Poland. The nuclear part of the lens is affected and previous reports from Sweden and France for this type of feline cataract suggest that a recessive mode of inheritance is probably involved. Results Presumed congenital or neonatal cataract involving the posterior nuclear part of each lens was initially diagnosed in a 12 month old male Bengal cat. As both parents and a sibling were also affected with cataract, a group of 18 related and 11 non-related cats was then subsequently examined. Eight related cats and one non-related cat were found to be similarly affected. A breed survey was then completed using an additional five centres across Poland and a further 190 related cats were examined. A total of 223 cats have been involved in this study, with 75 (33%) being affected with several types of cataract and 67 (30%) being specifically affected with the same or similar...

Veterinary Ophthalmology, 2017

Objective To describe the prevalence and the types of eye disorders that are known or presumed to be inherited (KP-HED) in three small Italian dog breeds. Animals Three small Italian dog breeds: Maltese, Bolognese, and Italian Greyhound. Procedures All dogs of the breeds selected for this prospective observational study that underwent a complete ophthalmic examination between 1994 and 2015 were included. General and proportional KP-HED prevalence with 95% confidence intervals were reported. Results Three hundred and six of 462 dogs were affected by at least one KP-HED (66.2%; 95% CI: 61.8%-70.4%). In the entire population, the five most common KP-HED were cataract (n = 122; rate on the total number of KP-HED: 31.4%), entropion (n = 56; 14.4%), keratoconjunctivitis sicca (n = 33; 8.5%), retinal dysplasia (n = 24; 6.2%), and persistent pupillary membrane (iris to iris) (n = 21; 5.4%). The most common KP-HED in each breed were cataracts in the Maltese (35.1%) and in the Bolognese (24.2%), and presentation of vitreous in the anterior chamber in the Italian Greyhound (46.7%). Conclusions Clinicians should be aware of KP-HED that commonly affect three small Italian dog breeds. Breed standards should be reconsidered, and breeding programs should be directed at limiting such disorders.