Acral Mutilation Syndrome (AMS) Testing Guide for Dogs

Acral mutilation syndrome (AMS) is a rare, hereditary neurological condition in dogs causing affected animals to excessively lick, bite, and groom their own limbs and paws. This is driven by a loss of pain sensation and feeling in these areas, meaning the dog cannot detect injury or discomfort, which unfortunately leads to severe self-inflicted damage.

Though AMS may appear as behavioural, it is a polyneuropathy affecting the sensory nerves. Affected dogs may gnaw off claws or even parts of their footpads and digits. This condition has a profound impact on the dog's welfare and health, so it is essential for affected dogs to be excluded from breeding to prevent passing the gene on.

Recognition of AMS's inherited nature has led The Kennel Club and British Veterinary Association to establish testing schemes. These schemes help breeders identify if their dogs carry or are affected by the AMS gene mutation, guiding responsible breeding choices to reduce incidence in future generations.

Understanding Acral Mutilation Syndrome

The first sign of AMS is persistent and obsessive grooming of the paws, limbs, and feet, often resulting in raw, bleeding wounds. Puppies may be smaller than their littermates and show these signs before weaning. Because they do not feel pain normally, they may cause damage so severe it includes claw loss, footpad ulceration, and even fractures without limping or visible discomfort.

The self-mutilation is a result of the dog’s inability to sense pain or touch normally in these areas, which escalates as the dog continues to bite absent pain feedback. Multiple limbs can be affected, and despite the injuries, affected dogs may still walk normally.

Breeds at Risk of AMS

AMS has been reported primarily in certain pedigree breeds with inherited gene mutations affecting nerve function. Most notably, it affects Cocker Spaniels puppies, English Setter puppies, German Shorthaired Pointer puppies, and Miniature Schnauzer puppies. These dogs are genetically predisposed and affected from a young age, often showing symptoms before leaving their litter.

Genetic Inheritance of AMS

AMS is an autosomal recessive condition, meaning a dog must inherit two copies of the mutated gene—one from each parent—to develop the condition. Dogs with just one mutated gene are carriers and do not show symptoms but can pass the gene to offspring.

• If both parents are clear, puppies will be free of the gene.
• If both parents are affected, all puppies will have AMS.
• Breeding two carriers results in a 25% chance of affected puppies, 50% carriers, and 25% clear puppies.
• Affected bred to clear dogs produce all carrier puppies.
• Breeding an affected dog to a carrier leads to 50% affected and 50% carriers.

AMS Genetic Testing for Responsible Breeding

Breeders are advised strongly to test their breeding stock for AMS status to avoid producing affected puppies. The test involves a simple DNA sample, typically a cheek swab or blood sample, which is sent to an approved laboratory such as those accredited by The Kennel Club.

Testing is available for the breeds identified as at risk, and importantly, the dog's status (Clear, Carrier, or Affected) will be recorded in a breed health database. This transparency helps breeders make informed mating decisions.

What Testing Involves

• Sample collection: Buccal (cheek) swabs or EDTA blood samples collected by a vet or trained person.
• Lab analysis: DNA testing to identify presence or absence of mutant alleles.
• Result interpretation: Dogs are classified as Clear (no mutation), Carrier (one mutated gene), or Affected (two mutated genes).

Breeding Recommendations Based on Results

• Clear dogs: Can be safely bred with any status without producing affected puppies.
• Carrier dogs: Should only be bred with Clear dogs to avoid affected puppies.
• Affected dogs: Should not be bred due to the likelihood of affected offspring and welfare concerns.

Promoting Responsible Pet Ownership

If you are considering adding one of the susceptible breeds to your family, always seek puppies from reputable breeders who actively test for hereditary conditions like AMS. Responsible breeders share health test results openly and work to reduce inherited diseases.

For existing pet owners, if your dog shows signs of excessive licking or self-injury to the limbs or paws, consult your vet promptly to diagnose the cause and manage any injuries or infections with compassionate care.

Conclusion

Acral mutilation syndrome is a distressing inherited condition affecting certain breeds that impairs sensation in the paws, causing self-mutilation. Genetic testing is a powerful tool for breeders to prevent spreading AMS in the pedigree population. Responsible pet ownership means being informed about hereditary health risks and making breeding and buying choices that prioritise animal welfare.

Consult your vet or breed club for AMS testing details and always support ethical breeding practices for the health and happiness of future generations of dogs.