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Episodic Falling Syndrome (EFS)
| Acronym: | EFS |
| Gene: | BCAN |
| Mutation: | g.41325010_41340731delinsAAGGCC |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
The episodic falling syndrome is a syndrome of muscle stiffness and collapse, a paroxysmal hypertonicity disorder found in Cavalier King Charles spaniels. It is a recessive hereditary condition and is often mistaken for epileptic seizures. It is caused by a deletion in the BCAN gene, encoding the brain-specific extracellular matrix proteoglycan brevican which has an essential role in the formation of perineuronal nets governing synapse stability and nerve conduction velocity. Episodes begin between fourteen weeks and four years of age and are triggered by exercise, stress, or excitement and characterized by progressive hypertonicity throughout the thoracic and pelvic limbs, resulting in a characteristic ‘deer-stalking’ position and/or collapse. Between episodes, dogs appear to be completely normal neurologically. Carriers are found to be extremely common (12.9%).
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:
Gill, J.L., Tsai, K.L., Krey, C., Noorai, R.E., Vanbellinghen, J.-F., Garosi, L.S., Shelton, G.D., Clark, L.A., and Harvey, R.J. (2012). A canine BCAN microdeletion associated with episodic falling syndrome. Neurobiol Dis 45, 130–136.