Bone disorders in the dog: A review of modern genetic strategies to find the underlying causes

Abstract

SUMMARYIn man, the genetic defects of more than 600 inherited diseases, of which at least 150 skeletal diseases, have been identified as is the chromosomal location for approximately 7000 genes. This rapid progress has been made possible by the generation of a genetical and physical map of the human genome. There is no reason to believe that for the dog not a similar development may occur. This review is therefore focussed on the use of novel tools now available for comparative molecular genetic studies of skeletal dysplasias in the dog. Because the genomes of mammals at the subchromosomal level are very well conserved, likely candidate disease genes known from other species might be considered. In this review, formation of the bones and the most important canine disorders of the skeleton influencing locomotion will be discussed first. The canine disorders discussed are canine hip dysplasia, the three different forms of elbow dysplasia (fragmented coronoid process, ununited anconeal process, osteochondrosis dissecans and incongruency) and dwarfism. Where possible a link is made with similar diseases in man or mouse. Then, the molecular biological tools available to analyse the genetic defect will be reviewed and some examples discussed.

Estimated Breeding Values for Canine Hip Dysplasia Radiographic Traits in a Cohort of Australian German Shepherd Dogs

“…The PennHip method [3] has also been endorsed more recently in Australia. The BVA/KC Scheme is based on a radiograph taken with hips in extension.…”

Anthropometric measurements of the scapula, humerus, radius and ulna in Labrador dogs with and without elbow dysplasia

“…In other words, the incidence of Labrador bitches with ED may appear relatively higher because phenotypic plasticity allows reduction of the male incidence as a result of human management of the environmental risk factors, which affect males more. Our survey showed that the owners/breeders in this study were well versed in the effects of over‐nutrition, early rapid growth and early vigorous exercise in the production of ED, as presented in the veterinary literature 4,8,11,15–17 . In nearly all of our subjects, these environmental factors were well controlled.…”

“…There has been an evolution, in more recent times, to leaner, lighter, early‐exercise‐controlled Labradors, as a result of the veterinary literature regarding the influence of over‐nutrition, over‐early activity and over‐early growth rate on ED 5,6,8,16,17 . A relative increase in the number of bitches with ED could reflect this change in controlling of the environment having a greater impact on the dogs’ phenotype.…”

“…In addition, environmental factors such as nutrition, early rapid growth and overactivity or trauma may add to the ED phenotype 2,5–15 . The prevalence of ED in males has been previously established, 16–19 and Everts et al have suggested that ED is polygenetic and has a multifactorial aetiology 20…”

Canine Chondrodysplasia Caused by a Truncating Mutation in Collagen-Binding Integrin Alpha Subunit 10

“…In addition to humans, inherited chondrodysplasia occurs in the pure-bred dog [21], [22]. The population structure of modern dog breeds is characterized by high inbreeding, severe bottlenecks and isolation, all of which have increased the incidence of simple and complex inherited diseases [23], [24].…”