Episodic Falling Syndrome (EFS)

Episodic Falling Sydrome

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Price: $45.00Price: £40.00

Breeds: Bernalier, Cavachon, Cavalier King Charles Spaniel, Cavapoo, Goldadoodlier, Goldalier, King Charles Bernedoodle, King Charles Spaniel, Mixed Breed, Unspecified


Episodic Falling Syndrome (EFS) is an autosomal recessive disorder predominantly found in King Charles Spaniels. It is characterized by muscle stiffness and collapse of the dog during times of excitement, stress, or exercise. Episodes can last for several seconds or several minutes. Approximately 13% of King Charles Spaniels are carriers for the mutation responsible for EF.

Signs associated with EFS typically appear around the time that the puppy is three to seven months old. These symptoms are brought on during times of high excitement, stress, or exercise. Signs include:

  • Sudden rigidness in rear muscles

  • Muscle spasms

  • Limb rigidity

  • Muscle stiffness

  • Loss of coordination

  • Stumbling

  • Falling or collapse

  • Yelping

  • Arched back

  • Overheating due to being unable to pant and release heat

Due to a deletion in the BCAN gene, a protein required for proper formation of the central nervous system is not produced in appropriate proportions. EFS is commonly mistaken with epileptic seizures however dogs do not lose consciousness like they do with epilepsy. Dogs seem conscious of what is happening to them and often stand up as if nothing happened after an episode. EFS can be managed with appropriate care, although some dogs have such extreme episodes that they are euthanized to maintain quality of life. Fortunately, this disorder often improves with therapy and mild cases experience stabilization of the disease once the puppy reaches a year old.

EFS is an autosomal recessive disorder. This means that a dog must inherit two copies of the mutation in order to present symptoms of EFS. A dog with one copy of the mutation is known as a carrier and does not present symptoms. If two carriers are bred to one another, there is a 25% chance per puppy born that they will develop symptoms of EFS and a 50% chance per puppy born that they will also be carriers of EFS. Although EFS is treatable, the best way to manage EFS is through prevention. Genetic testing can reveal the likelihood of a dog developing EFS and can inform a breeder of major health concerns. 

Possible Results

Genotype Description
EFS/EFS Affected: Dog has two copies of the Episodic Falling mutation and will pass the gene on to every offspring.
n/EFS Carrier: Dog has one copy of the mutation associated with Episodic Falling. The mutation may be passed to offspring.
n/n Clear: Dog is negative for mutation associated with Episodic Falling.


Gill JL, Tsai KL, Krey C, Noorai RE, Vanbellinghen JF, Garosi LS, Shelton GD, Clark LA, Harvey RJ. A canine BCAN microdeletion associated with episodic falling syndrome. Neurobiol Dis. 2012 Jan; 45(1):130-6. [PubMed: 21821125]

Herrtage ME, Palmer AC. Episodic falling in the cavalier King Charles spaniel. Vet Rec. 1983 May 7; 112(19):458-9. [PubMed: 6868317]