Canine muscular dystrophy and affected breeds

Muscular dystrophy is a chronic and progressive hereditary disorder that causes muscular degeneration, which over time, leads to loss of movement, weakness, and the destruction of the cells of the body’s muscle tissue. The condition can affect people as well as dogs, and there is a significant amount of crossover and exchange of knowledge between the study of the condition in humans, and that of dogs.

As a hereditary condition, the risk factors for muscular dystrophy are significantly higher for certain breeds and types of dogs than for others, and it is a good idea to learn more about the condition if you are considering buying a dog or a puppy of one of the breeds that are at particular risk.

In this article, we will look at canine muscular dystrophy in more detail, including the types of dogs it most commonly affects, and what it means for them. Read on to learn more.

What is muscular dystrophy?

Muscular dystrophy is a catch-all term to refer to any one of a group of several strains or presentations of the condition, each of which are distinct from each other but that ultimately, act in broadly the same fashion.

The word “dystrophy” means tissue degeneration, and muscular dystrophy affects the skeletal muscles, weakening them over time and leading to the progressive death of the cell and tissue structures of the muscles, muscle protein, and loss of strength and the normal range of movement. Over time, the condition can lead to the dog becoming able to walk at all or perform other muscle-related tasks, without the accompanying loss of sensation that accompanies total paralysis.

Dystrophin, the muscle protein that is responsible for the health and regeneration of muscle tissue, becomes dysfunctional and does not regenerate properly in affected dogs, which is the key to the condition’s action.

Why does it occur?

Muscular dystrophy in dogs is hereditary, and is passed on from dog to dog via their breed line rather than being something that is caught or contracted. The gene for muscular dystrophy in dogs is carried in affected dogs by the “X” chromosome, which is present in female dogs in two copies, and in male dogs, only one. Because male dogs have two copies of the X chromosome, this means that male dogs need only inherit one faulty “X” chromosome from one of their two parent dogs to develop the condition, while for female dogs, it is necessary to inherit two copies of the gene, one from each parent, in order to develop the condition.

This means that muscular dystrophy is more common in male dogs than females, although both males and females are equally likely to be carriers of the faulty gene. Within any given litter, it is entirely possible that male puppies will be affected with the condition, whilst females of the same litter may not be.

What sort of dogs does it affect?

As mentioned, male dogs are at greater risk from the condition than females, but due to the genetic hereditability of the condition, certain breeds of dog, and breed lines from within those breeds, have higher risk factors for the condition than others.

The breeds of dog most commonly affected with the condition include:

• The Belgian Malinois
• The Golden retriever
• The German shorthaired pointer
• The Samoyed
• The Labrador retriever
• The Irish terrier
• The Welsh corgi
• The Miniature Schnauzer

Cross breeds and hybrids consisting of a mixture of one of these breeds and another dog may also be affected, but outcrossing brings with it the benefits of hybrid vigour, and so the condition is much less likely to present in mixed breed dogs than pedigrees.

How can you identify it?

Muscular dystrophy in dogs usually becomes obvious in puppies before they reach the age of twelve weeks old, and so dog breeders in particular should familiarise themselves with the symptoms of the condition, as should potential buyers of puppies of high-risk breeds.

The symptoms of the condition can be variable in terms of their presentation and how badly they affect the dog in question when they are young, but generalised weakness or wobbliness and an inability or apparent unwillingness to exercise and move normally is one of the key symptoms, and muscle spasms or twitching may also become apparent after a period of observation.

Affected dogs may also display breathing difficulties, problems swallowing food or eating normally, and potentially, will salivate or slobber heavily even when this is not a normal breed-specific trait.

It is important not to ignore any of these symptoms in any puppy or litter that you might be considering buying from, as muscular dystrophy is a serious, lifelong condition that is expensive to manage, and will greatly limit what your dog is able to do.

What can be done for affected dogs?

Unfortunately, muscular dystrophy cannot be cured or reversed, and there is no truly effective way of curbing or managing the progression of the condition either. Many puppies with the condition will not live to see their first birthday, and even in dogs in which the development and progression of the condition is slower are unlikely to live to old age, and their quality of life as the condition worsens will be mediocre at best.

Obviously, dogs with muscular dystrophy or with a history of the condition in their breed line should not be used for breeding from, and puppy buyers should ask the breeders of dogs of affected breeds if there is any history of the condition in the puppies’ ancestry.