Shaking puppy syndrome or Hypomyelination

Shaking Puppy Syndrome or SPS, is a disorder that can affect certain breeds negatively impacting nerve bundles or white matter found around a dog's brain. With this said, studies have established that the problem which involves the breakdown of myelin that surrounds nerve fibres both in the brain and in other areas of a dog's system including their spinal cords, brainstem and other areas around the brain, is responsible. The scientific name for the disorder is Spongiform Leuco-Encephalo-Myelopathy or SLEM as such both SPS and SLEM are the same condition.

Symptoms associated with SPS

The first time the condition was reported was in 2012 when it was seen that puppies began "shaking" as they tried walking for the first time when they were typically about 2 weeks old. The most affected areas were a puppy's hindquarters which shook more than other parts of the body. Over time, more puppies in the UK were reported as suffering from the condition with the symptoms first being seen they were around 2 weeks old, although other puppies showed symptoms when they were between the ages of 8 and 12 weeks old. The reason why some puppies display symptoms that much later needs further investigation.

With this said, affected puppies in a same litter typically show symptoms of SPS at the same time rather than at different points in their lives. Other signs apart from shaking include puppies having trouble gaining weight and condition. It is thought that this is due to them shaking so much they are unable to feed as they should and that these tremors use up a tremendous amount of their energy.

Affected puppies also tend to be that much smaller, weighing less than their littermates when born and even before they show any signs of there being something wrong with them. However, once a puppy is diagnosed as suffering from the condition, it is much kinder to have them put to sleep rather than to let them suffer, although a few puppies have survived thanks to the intensive care and nursing given by their owners once the condition has been diagnosed by a vet. With this said, a puppy would never make a full recovery because of the brain damage they suffer as a result of suffering from shaking puppy syndrome.

As previously mentioned, the function of myelin is to insulate nerve fibres found in the brain, but it also helps transmit nerve impulses in each nerve fibre too. Any sort of negative impact to this function has a serious effect because nerve impulses no longer work as they should. The result is just as serious with dogs showing neurological issues that leads to incoordination, seizures or tremors, hence the name "shaking puppy syndrome".

What breeds are the most susceptible?

There are certain breeds that seem to be more predisposed to suffering from the condition and this includes the following:

Border Terriers

Springer Spaniels

Australian Silky Terriers

Golden Retrievers

Weimaraners

Chow Chows

Dalmatians

Welsh Springer Spaniel

Bernese Mountain Dogs

Samoyeds

Vizslas

It is assumed the condition is inherited with research having established that a genetic mutation exists in specific breeds, namely the Weimaraner and Springer Spaniel.

How SPS is inherited

Both parent dogs must have the gene mutation to pass the disorder onto their offspring with some puppies being affected by SPS whereas others could be "clear" and some could be "carriers". If just one parent carries the mutated gene and passes this on to their puppies they will be "carriers" and although free of any symptoms, they can pass the mutation on if they are used for breeding purposes. Dogs that do not carry the gene mutation are referred to as being "clear" when DNA tested for the condition.

It is worth noting that if mated even two "carriers" could produce puppies that can test "clear", "carrier" or "affected" and it is estimated that 25% of puppies could be clear, 25% could be affected and 50% could test clear.

Treatment options

Just why a dog inherits a faulty metabolic process that leads to them suffering from SPS remains unknown and as such, sadly, there is no treatment or therapy available for puppies suffering from the disorder. It is important to understand that any sign of a puppy recovering from SPS or where an improvement is seen, is typically because their condition is not as severe and therefore any degeneration in the insulation myelin provides is less severe too. With this said, if there is some improvement, this could be due to a little in the way of regeneration of the myelin in a puppy's brain that occurs as they mature, but more research is necessary to establish whether this is the case.

Diagnosing the problem

It has been established that MRI scans can be useful when identifying any signs of myelin changes in an affected puppy's brain. This together with a visual diagnosis of a puppy and their lack of coordination, tremors and difficulty in putting on condition and weight, would establish whether a puppy is suffering from shaking puppy syndrome.

DNA testing is essential

Fortunately, there is now a DNA test available and all breeders are strongly advised to have their dogs tested before using them for breeding purposes. This is the only way of reducing the chances of puppies inheriting shaking puppy syndrome.

Much research is being undertaken in America at the University of Missouri and more recently this has been carried out with the Kennel Club Genetic Centre which is located at the Animal Health Trust, being closely associated with the studies. In the UK, the Liverpool Veterinary School and the Glasgow Veterinary School are also carrying out research into SLEM. The DNA test is available through the Animal Health Trust (AHT).