Storage diseases are inherited metabolic disorders characterized by the accumulation of certain substances in various tissues in abnormal amounts. The two most commonly reported storage diseases in veterinary medicine are lysosomal and glycogen storage disease.
Storage diseases of the nervous system are inherited deficiencies of particular enzymes creating an inability to perform normal metabolic functions. Both dogs and cats can be affected, although the disease is extremely rare. Because it is a heritable disorder,
puppies and kittens are most commonly affected.
Lysosomal storage diseases are seen most commonly in the German shorthaired pointer, English setter, beagle, cairn terrier, blue tick hound and West Highland terrier.
Glycogen storage diseases are seen most commonly in the German shepherd dog.
What to Watch For
Lysosomal storage diseases may affect many organs; however, neurologic signs tend to predominate. Watch for:
Failure to thrive
Ataxia (poor balance)
Seizures
Exercise intolerance
Behavioral changes
Compromised vision
Signs associated with glycogen storage diseases are often vague and nonspecific. Watch for:
Growth and muscle development failure
Fainting
Seizures
Diagnosis
Breed and clinical history raise an index of suspicion. Your veterinarian will likely perform the following tests:
Complete blood count (CBC)
Biochemical profile
Urinalysis
Thoracic (chest) and abdominal X-rays
Abdominal ultrasound
Tissue biopsy
Measuring enzyme activity
Treatment
Supportive fluid and electrolyte therapy may be necessary in weak and dehydrated patients.
The main objective of treatment with glycogen storage diseases is the control and prevention of hypoglycemia (low blood sugar) with appropriate dietary therapy.
It is important to restrict activity and avoid stairs in patients with lysosomal storage diseases.
Affected individuals may be at high risk for developing secondary infections, therefore should be closely monitored.
Home Care and Prevention
Maintaining a good nutritional plan in the patient is essential. Routine monitoring of blood sugar, growth and hydration status is especially important with glycogen storage disease. Lysosomal storage diseases are progressive and ultimately fatal.
Be careful, as inbreeding increases the risk if the defective gene is in the family. Do not breed affected individuals and avoid using the parents of affected individuals in a breeding program.
