Problems with the skeletal and muscular systems are among the most common disorders among purebred dogs.

However, owners of mixed breed dogs with a purebred ancestry often have no idea if their dog is at risk of developing disorder of the skeleton or muscle. This is because many mixed breed owners do not know if their dog has a purebred parent of grandparent.

Mixed breed Dog DNA tests, only available in the past few years, can tell if a mixed breed dog has parent or grandparent that was a purebred. Your vet can determine if your dog is at risk of inheritied genetic disorders once your vet knows the purebred ancestry of your mixed breed dog.

Common disorders include hip and elbow dysplasia, and patellar luxation. Other disorders of the muscular and skeletal system include:

  • Cervical vertebral instability (Wobbler syndrome)
  • Craniomandibular ostopathy (lion jaw)
  • Elbow dysplasia – OCD, osteochondrosis of humeral condyle, fragmented medial coronoid process, ununited anconeal process, incongruent elbow
  • Hemivertebra
  • Hereditary myopathy
  • Hip dysplasia
  • Intervertebral disk disease
  • Legg-Calvé-Perthes disease
  • Masticatory myositis
  • Myotonia
  • Odontoid process dysplasia
  • Osteochondrodysplasia – skeletal dwarfism
  • Panosteitis
  • Patellar luxation
  • X-linked muscular dystrophy

Specific registries record muscular and skeletal health and genetic disorders in dogs, and that provide testing for specific disorders. A good breeder should be affiliated with one or more of these organizations.

The OFA (Orthopedic Foundation for Animals) is an organization that tests dogs for a variety of health disorders, including hip dysplasia and elbow displaysia, and thyroid and cardiac disorders. Reputable breeders will most likely have used the OFA for their testing. You can search the OFA’s online database to determine the relative incidence of health or genetic disorders in specific dog breeds.

You can find more information at the OFA’s website at www.offa.org.

The Institute for Genetic Disease Control in Animals (GDC) is a non-profit organization. It is an international open registry for canine orthopedic genetic diseases, eye, heart, cancer, Globoid Cell Leukodystrophy, skin diseases (only for some breeds), and other genetic diseases. The GDC has an online, searchable registry that contains all breeds and known and suspected genetic diseases. The database contains information from veterinary screening of individual dogs.
You can find more information at the GDC’s website at www.gdcinstitute.org.


PennHIP, the University of Pennsylvania Hip Improvement Program, is also often used to detect hip dysplasia, or susceptibility to hip dysplasia, in dogs. Canine hip dysplasia is a serious disorder, mostly of large breeds, that can result in osteoarthritis in the hip, and potentially lead to lameness. Reputable breeders often use PennHIP testing to test their dogs for hip dysplasia. Currently, the tests can only be done on puppies over 16 weeks of age.
You can find more information at PennHIP’s website at www.pennhip.org.

Hip dysplasia
This occurs when there is a disorder in the way a dog’s thigh bone fits into the hip socket. Over time, the joint may degenerate and develop osteoarthritis, causing pain, weakness and lameness in the joint. Hip dysplasia gets worse with time, can be a crippling disorder, and occurs mainly in large and giant breeds.

Hip dysplasia can be caused by mutations in many different genes, none of which are well identified. As a result, there is no genetic test for hip dysplasia. However, health screening can identify dogs that are likely to develop the disorder. Ask any breeder of large or giant dogs for hip certification in their breeding dogs for several generations back.

Elbow dysplasia
Elbow dysplasia actually refers to a collection of different disorders, including ununited anconeal process. osteochondrosis of the medial humeral condyle, fragmented medial coronoid process, and incongruent elbow. These disorders often affect both front legs, and cause elbow pain and lameness in the forelimbs. It is currently thought that these disorders are actually the result of a single disease, osteochondritis dissecans (OCD). OCD occurs when cartilage develops abnormally.

Elbow dysplasia occurs primarily in large and giant breeds, and affects male dogs more often than females. It is common in the following breeds:

  • Basset Hound
  • Bernese Mountain Dog
  • Bloodhound
  • Bouvier des Flandres
  • Chow Chow
  • German Shepherd
  • Golden Retriever
  • Great Pyrenees
  • Irish Wolfhound
  • Labrador Retriever
  • Mastiff
  • Newfoundland
  • Rottweiler
  • Saint Bernard
  • Weimaraner

Like hip dysplasia, elbow dysplasia results from disorders in several genes, but it is not known which genes. There is no genetic testing available for the disorder, but health screening can identify dogs that are likely to develop elbow dysplasia. Ask any breeder of large or giant dogs if their breeding dogs for several generations back have been screened for elbow dysplasia.

Patellar luxation
Patellar luxation results from a disorder in the way the patella (knee cap) fits into the femur (thigh bone). Patellar luxation occurs when the knee cap slips out of the groove in the femur. Over time, it can lead to degenerative changes, including osteoarthritis, and can be painful and result in lameness.
Patellar luxation is common in many smaller breeds, including:

  • Basset Hound
  • Boston Terrier
  • Chihuahua
  • Lhasa Apso
  • Miniature Poodle
  • Pomeranian
  • Pekingese
  • Shih Tzu
  • Silky Terrier
  • Toy Poodle
  • Yorkshire Terrier

While patellar luxation results from disorders in several genes, it is not known which genes cause the disorder. There is no genetic test currently available.

Health screening can identify dogs with patellar luxation. Ask any breeder if their breeding dogs for several generations back have been screened for patellar luxation.

Genetic Skeletal and Muscular Disorders in Mixed Breed Dogs

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