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CNS atrophy with cerebellar ataxia (CACA) - Belgian Shepherd Type
| Acronym: | CACA |
| Gene: | SELENOP |
| Mutation: | g.66946539 _66963863del17325 |
| Inheritance: | Autosomal Recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Central nervous system (CNS) atrophy with cerebellar ataxia (CACA) in dogs is a neurodegenerative disease characterized by uncoordinated movements which are a relatively non-specific sign. There is a form of this disease linked to a specific genetic mutation in Belgian Shepherds. In Belgian Shepherds, symptoms of variable severity develop early during the first few weeks of the dog’s life and include uncoordinated movements, intention tremor, reduced swallowing reflex, general elevated muscle tone and spastic fits. The disease reduces the quality of life of affected dogs and in severe cases requires euthanasia. CACA in Belgian Shepherds is caused by a genetic mutation, more specifically a large deletion in the SELENOP gene that encodes a protein called selenoprotein P required for selenium transport into the central nervous system. The absence of this protein results in extremely low blood and brain selenium levels which is required for the function of various enzymes in the brain. Selenoprotein P itself is probably directly involved in signaling processes in the brain. These deficiencies result in the formation of lesions caused by the death of neurons in various parts of the brain.
CACA is inherited as an autosomal recessive trait. This means that two copies of the mutated gene are required for the disease to develop. Belgian Shepherds with only one copy of the mutated gene won’t develop the disease but act as carriers that can potentially pass the mutation to their offspring. Early detection by genetic testing can identify Belgian Shepherds that carry the mutation and inform the breeders’ decisions when selecting mating pairs. This can be used to avoid unintentional breeding of infected puppies.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Christen, Matthias, et al. "Deletion of the SELENOP gene leads to CNS atrophy with cerebellar ataxia in dogs." PLoS genetics 17.8 (2021): e1009716. https://doi.org/10.1371/journal.pgen.1009716