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Canine Multiple System Degeneration (CMSD) Chinese Crested Type
| Acronym: | CMSD |
| Gene: | SERAC1 |
| Mutation: | c.128+1_128+4delGTAA |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Canine multiple system degeneration Chinese Crested Type (CMSD) is an early onset autosomal recessive movement disease. It is a progressive inherited neurological disease that affects Kerry Blue Terriers (KBT) and Chinese Crested Dogs (CCD). The CMSD was for the first time recognized in the 1940s in the Kerry Blue terrier dog and is commonly called PNA among the Kerry Blue terrier breeders. The first clinical signs in the affected dogs are recognized by a tremor of the head, which is most noticeable during the dog’s attempt to eat. The first symptoms start developing along with cerebellar ataxia already at 3–6 months of age. At this early stage, the affected dogs will exhibit a goose-stepping gait and infrequent falls. Also, in the case of histopathological examination, loss of the Purkinje cells in the cerebellum is prominent. By 6-8 months of age, the nature of movement disorder changes, and falls become more frequent. The dog starts shifting their body weight, until the point where they begin to stumble forward. By the time of 12-18 months of age, the dog’s instability is severely developed and the dog is incapable of making any voluntary movement, it becomes akinetic. An attempt of standing independently ends in falling. The disease affects a dog’s life length and most dogs die due to disease complications or are euthanized by 18 months of age. No matter the severity of the disease, affected dogs show normal mentation and social behavior.
The canine multiple system degeneration of the Chinese Crested type, as well as the Kerry Blue terrier type, is caused by a mutation in the SERAC1 gene, which is located on chromosome 1. The primary symptom of the affected dogs is a movement disorder, caused by motor system degeneration. Motor system degeneration occurs due to the degeneration of neurons in one of the midbrain regions and the loss of cerebellar cells. CMSD course and symptoms appear very similar to Parkinson’s disease in humans. Parkinson’s disease is caused by a mutation in a gene that is localized in the same gene region as the SERAC1 gene.
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:
O’Brien, D. (2005.): Genetic Mapping of Canine Multiple System Degeneration and Ectodermal Dysplasia Loci. Oxford Journals Volume 96, Issue 7.
Zeng, R. (2013.): Molecular genetic studies in canine inherited diseases including neonatal cerebellar ataxia, degenerative myelopathy and multiple system degeneration. Dissertation.