What Is Neuronal Ceroid Lipofuscinosis?
Neuronal Ceroid Lipofuscinosis (NCL) is a group of severe neurodegenerative diseases resulting from the intracellular accumulation of wax-like lipid materials in neurons. It affects the cerebellum, other areas of the brain and the spinal cord.
Numerous mutations responsible for spontaneous neuronal ceroid-lipofuscinosis have been documented in domestic and research animals including sheep, cattle, mice and dogs. Mutations in canine orthologs of human TPP1, CLN5, CLN8 and CTSD have been discovered. Recently a new form of the disease in a Miniature Dachshund with a mutation in PPT1 has been described.3
Signs & Symptoms
Affected dogs are typically less than 1 year old; however, they may not show clinical signs until they mature. The majority of dogs begin to exhibit clinical signs between 12 and 18 months of age. The disease progresses over 2 – 3 years and is manifested by:
- Uncoordinated gait
- Difficulty in swallowing
- Vision and hearing loss
- Nystagmus (Rapid eyeball movement)
- Increased nervousness
- Decreased interactions with other dogs in the household
- Severe loss in the ability to recognize or respond to commands or his name
- Loss in the ability to recognize the primary owner or other people in the household
- Increased sensitivity to loud noises
- Circling behavior
- Increasing inappropriate vocalization
- Loss of ability to climb stairs or other obstacles
- Loss of coordination
- Severe loss of vision
- Persistent head movements
- Bumping into obstacles
- Enlargement of the nerves of the forelimbs can be detected
- At a later stage, seizures and tremors develop
Diagnosis of ceroid lipofuscinosis is based upon clinical signs, especially in a susceptible breed. Cerebrospinal fluid analysis is usually normal but may reveal increased protein levels with a normal cell count. Computed tomographic (CAT) or magnetic resonance imaging (MRI) of the brain may reveal brain atrophy and abnormal brain-tissue density.
At present, the prognosis for the lysosomal storage diseases in dogs and cats is grave. For the majority of these disorders, affected animals are euthanized within the first year of life due to progressive worsening neurological dysfunction.
Despite the poor outlook for this disorder, bone marrow transplantation and lysosomal enzyme replacement therapy have been successful in some human and animal cases. Gene transfer therapy is also being actively investigated and will hopefully be available in the future.
- M.P. Mattson – Genetic Aberrancies and Neurodegenerative Disorders
- Curtis W. Dewey – A Practical Guide to Canine and Feline Neurology
- Sanders et al. – A Mutation In Canine PPT1 Causes Early Onset Neuronal Ceroid Lipofuscinosis In A Dachshund