Hip joint Dysplasia (HD) is a hereditary maldevelopment of the hip joint that occurs in many breeds of dogs.
HD develops only during the growth of the animal. There are different approaches regarding the origin. While some authors assume that primarily a maldevelopment of the acetabulum and possibly also of the femoral head is responsible for the formation of HD, other authors see primarily the presence of a loose joint (subluxation, luxation) as a causal criterion. Osteoarthrosis is a frequent consequence of the dysfunction of the hip joint caused by this dysplasia.
In diagnosis, a distinction must be made between HD as a clinically manifest disease associated with pain and lameness and the classification of radiographic findings as a basis for breeding selection. According to various studies, clinical symptoms do not occur in all animals with changes in the hip joint and do not provide any information about the severity of the deformity. Thus, a reliable diagnosis can only be made radiographically.
Genetics and environment
Genetic factors play the major role in the development of HD, which has been proven by numerous studies. However, it has also been proven that environmental factors such as feeding, husbandry and exercise have an influence on the development of HD in animals that are susceptible from a genetic point of view. The decisive factor, however, is the genetic predisposition, without which the disease cannot occur.
Current status of molecular genetic research
HD is a polygenic inherited trait, i.e. several genes are causally involved in the development of the dysplasia. Due to the progress in molecular genetic research in recent years, it is now possible to elucidate even such complex events. Problematic in the clarification of HD, however, are the already mentioned modulating environmental influences, which considerably weaken the significance of the radiographic findings with regard to the so-called genotypic HD breeding value, i.e. the genetically manifested susceptibility to HD.
Extensive research in the German Shepherd Dog has now identified markers for HD that can be used to select against HD. Further information on this marker test for HD in the German Shepherd can be found here.
In other dog breeds, the extent to which the results in the German Shepherd Dog can be transferred with regard to HD is currently being investigated.
In order to make further progress in the molecular genetic clarification of this disease - which is associated with many restrictions for the animal and often with high costs for the owner - we need blood samples from dogs of the various breeds that have been diagnosed in the course of the official HD X-ray examination. It does not matter to us which result your animal has. Every sample brings us one step further.