Download Dogs and Disease: Effects of Muscular Dystrophy by Glenn Kalick

Dogs and Disease: Effects of Muscular Dystrophy
by Glenn Kalick, D.V.M.
On January 22, there was a walk-a-thon at the Dreher Park Zoo with the proceeds
going to the Muscular Dystrophy Association. It was a wonderful event, with affected
children and adults and their supportive families walking or wheelchairing around the
zoo, enjoying the nice weather and appreciating the animal exhibits.
My family was at the primate exhibit when my son, who was having a good day and
wanted to walk instead of using his wheelchair, overheard another little boy talking to
his mother, saying that animals are lucky — they don’t get muscular dystrophy (MD).
My son turned to the boy and told him animals can get muscular dystrophy. “My father’s
a veterinarian and he told me,” said my son.
Ironically, in my senior year of veterinary school, I was given a topic to present and it
was on a form of MD in a litter of golden retrievers. Little did I know that my son would
have a form of MD. And I only own golden retrievers. Golden retrievers with muscular
dystrophy (GRMD) clinically resemble people with Duchenne Muscular Dystrophy (DMD).
This is an x-linked recessive disorder affecting approximately one in 3,500 newborn human
males in whom absence of the protein dystrophin causes progressive degeneration of
skeletal and cardiac muscle. Clinical signs of GRMD occur soon after birth, as pups are
often ineffectual sucklers and must be supplemented. As a result, they are typically
stunted in growth. As they get older, they develop a progressively stilted gait and atrophy
of certain muscle groups. They hyperextend some joints and overflex others. Some dogs
excessively drool, suggesting pharyngeal muscle involvement. Aspiration pneumonia
suggests esophageal muscle involvement. Cardiac failure due to cardiomyopathy can also
occur.
Muscular dystrophies are a diverse group of inherited, progressive and degenerative
polymyopathies that involve either a deficiency of or abnormality in proteins necessary
for proper muscle function. MD has been reported in humans, dogs, cats, mice, hamsters
and chickens. Some MDs affect many muscle groups and some target only specific muscle
groups. Regardless of the type of MD, clinical signs are related to muscle weakness,
usually at a young age. There are many breeds that have a predilection for MD. Bouvier
des Flandres, Brittany spaniel, Cavalier King Charles spaniel, German short-haired pointer,
golden retriever, labrador retriever, rottweiler, samoyed, and miniature schnauzer are just
a few of the susceptible breeds.
The conversation with my son continued for the whole event at the zoo. We would look at
the animal in an exhibit and he would come out of the exhibit and ask me if that animal can
get MD. “If a monkey got MD, how would it jump from tree to tree and not get tired?,” my
son asked me. I told him that there is such a close relationship between GRMD and the
human form of MD that extensive research is being done on breeding colonies of these
specifically affected golden retrievers and German short-haired pointers all over the world.
Most of the research using these dogs is focused on preclinical studies of potential treatments
of DMD in people.
When I told him this, the expression on his face was one of confusion. I asked him what he
was thinking and he told me that he was sad that any dog, especially a golden retriever,
could be affected with muscular dystrophy because he knows what it feels like. “When I get
home, I am going to give Connor and Kelly (our golden retrievers) a huge hug,” my son said.
Glenn Kalick, D.V.M., is the owner of Brookside Animal Hospital of Coral Springs.
The web site is www.Brooksidevet.com.