Canine spinal muscular atrophy is a genetic disorder that affects dogs, particularly those of small and toy breeds. It’s also known as hereditary motor neuron disease or HMD. In most cases, spinal muscular atrophy occurs due to an inherited mutation in a gene which codes for the production of a protein called SMN1, which plays an important role in motor neuron development.
The disorder causes progressive muscle weakening in their limbs and body, leading to paralysis and difficulty breathing. Signs of spinal muscular atrophy usually begin to appear at around three months old. Affected puppies can have signs of wobbliness and difficulty walking, which progressively become worse over time. Other common signs include a reduction in their muscle mass, an abnormal gait, and an inability to hold their head up.
In some cases, affected puppies will also have secondary complications such as aspiration pneumonia due to their difficulties eating and swallowing. Unfortunately, spinal muscular atrophy is a progressive disorder and there is no cure available. Treatment typically focuses on managing the signs of the disease and giving them supportive care in order to increase their quality of life. Supportive care can include physical therapy, medication to reduce their pain and discomfort, and nutritional support.
It’s important for breeders to be aware of the genetic mutation responsible for spinal muscular atrophy so that they can take steps to not to breed dogs with this mutated gene. Genetic testing can be used to identify carriers of the gene mutation and should be tested for before any puppies are bred. Any puppies born from carrier parents should not be used for breeding.
Symptoms of Canine Spinal Muscular Atrophy
The main symptom of spinal muscular atrophy is progressive muscle weakening in their limbs and body, leading to paralysis. Other signs include:
- Wobbliness and difficulty walking
- Reduced muscle mass
- Abnormal gait
- Inability to hold their head up
- Difficulty eating or swallowing
- Secondary complications such as aspiration pneumonia
Diagnosing Canine Spinal Muscular Atrophy
Spinal muscular atrophy is typically diagnosed based on a combination of clinical signs and laboratory testing. A veterinary examination can help determine if your dog has any of the common symptoms associated with spinal muscular atrophy. X-rays and ultrasound imaging can also be used to assess changes in their muscle and nerve structure.
In order to confirm a spinal muscular atrophy diagnosis, genetic testing should be used to identify the presence of a mutation in the gene responsible for producing the SMN1 protein. Depending on the dog breed, this test might be available through commercial laboratories or through your veterinarian.
Stages of Canine Spinal Muscular Atrophy
Spinal muscular atrophy is a progressive disorder, meaning that the symptoms of the disease become worse over time. The progression of spinal muscular atrophy can be split into three stages:
Mild Symptoms:
At this stage, affected puppies might have signs such as wobbliness and difficulty walking, but are still able to stand and walk on their own.
Moderate Symptoms:
At this stage, affected puppies are unable to stand or walk on their own and can start to have signs such as reduced muscle mass and an abnormal gait.
Severe Symptoms:
At this stage, affected puppies have difficulty breathing and are unable to move their limbs. Secondary complications such as aspiration pneumonia can occur due to difficulties eating and swallowing.
Treating Canine Spinal Muscular Atrophy
Treating spinal muscular atrophy typically focuses on managing the symptoms of the disease and giving your pet supportive care. Supportive care can include physical therapy, medication to reduce pain and discomfort, and nutritional support. Unfortunately, there is no cure for spinal muscular atrophy and disease progression can’t be stopped.
Preventing Canine Spinal Muscular Atrophy
In order to prevent spinal muscular atrophy from occurring in future generations of puppies, it’s important for breeders to be aware of the genetic mutation responsible for the disease. Genetic testing can be used to identify carriers of the gene mutation and should be tested for before any puppies are bred from your dogs.
Other steps to reduce the incidence of spinal muscular atrophy include breeding only healthy dogs that have not been affected by the disorder and avoiding inbreeding.