What is JLPP?

JLPP is an inherited neurological disease resulting in certain death for any puppy affected with it. This disease cannot be cured or prevented once the puppy is conceived. Neither can this disease develop during the life cycle of a dog nor be the result of complications from other illnesses. All puppies affected by this disease die very young – most before they are one year of age.

How is it inherited?

The JLPP gene is a recessive gene. This means that a puppy must carry two JLPP genes in order to be affected. This requires both parents to be carriers of the gene and for them both to pass on the gene to the puppy. Statistically, from a litter where both parents are carriers of the JLPP gene there is a 25% chance that a puppy will be affected (always lethal), 50% chance that it will be a carrier and 25% chance that the puppy will be clear of the gene. It is important to note that only an affected puppy (one that carries two JLPP genes) will have any symptoms from this disease. Any puppies born carriers (ones that have a single JLPP gene) or clears (ones with no JLPP genes) will never suffer from this disease.

What do the different JLPP status’s mean?

Clear: This puppy/dog does not carry any JLPP genes. If bred to another clear then 100% of puppies produced will be clear of the JLPP gene. If bred to a carrier then there is a 50% chance that a puppy will be clear and a 50% chance that it will be a carrier.

Carrier: This puppy/dog carries one JLPP gene. This dog will live a normal life, with no ill effects associated with this gene. A carrier should only ever be bred to a clear. Breeding a carrier to a clear will produce puppies with a 50% chance of being clear and a 50% chance of being a carrier. If the carrier is bred to another carrier (which should never be done) then they will produce puppies with 25% chance of being affected (always lethal), 50% chance of being a carrier and 25% chance of being clear.

Affected: This puppy carries two JLPP genes. Sadly this puppy will die at a young age – in most cases before it is one year old. Symptoms start at 12 weeks and will continue for a number of months until death. This dog should never be bred with under any circumstances.

What are the symptoms?

The first noticeable symptom of this disease is shortness of breath from minor physical activities and the inability to bark properly (if at all). Most owners, however, first notice a weakness in the puppy’s back legs. The puppy begins to lose co-ordination - eventually losing all function in the backend. This then progresses forwards and into the front legs until the puppy can no longer move under its own power. Eventually the puppy dies as the nerves in its body continue to shut down. In most cases the puppy is euthanized before this point.

What causes it?

JLPP is caused through the mutation of the RAB3GAP gene and is hereditary. It is a neurological disease which causes the puppy’s nervous system to shut down. The first nerves to begin to die are those that control the larynx (the longest nerve in the body), which is why the first symptom is shortness of breath and the inability to bark properly. The nerves that control functions farthest from the brain (i.e. Back legs) die first, which is why there is a progression forwards towards the brain.

What are the origins of this disease in the Rottweiler?

It is unclear when the JLPP mutation first occurred or was introduced in the Rottweiler. However, it is safe to assume that the mutation was restricted to an isolated bloodline (a line that was not commonly used by a large number of breeders in their breeding program). The gene is likely to have been passed down through the female line with very few offspring kept for breeding. It is likely at this stage that there were only a handful of breeding dogs from this bloodline in the population – of which not all would have been carriers. This is, of course, speculation, but, it is plausible.

In the 1950’s 5 Rottweilers were selected by the Russian Military to take part in their breeding program for the creation of a new breed – the Black Russian Terrier (BRT). This is where we get the first piece of evidence of the existence of the JLPP gene in the Rottweiler. Unfortunately (and unbeknown to them) it seems the Russians had inadvertently chosen one of the handful of carriers for their breeding program. The evidence suggests that the BRT introduced the JLPP gene into their breed from one of these 5 foundation Rottweilers as the gene exists in the same location for both breeds and the same test can be used for both. The 5 Rottweilers used to create the BRT are as follows:

Sarro (Date?) male (Unknown x Unknown)

Kastor (1947) male (Unknown x Unknown)

Tina (Date?) female (Unknown x Unknown)

Birma (Date?) female (Unknown x Unknown)

Nelli (Date?) female (Unknown x Unknown)

From the 1950’s until the 1980’s the JLPP gene continued to play a minor role in the Rottweiler population’s gene pool. Even after another 30 years since the gene was accidentally introduced to the BRT there would have only been a handful of carriers. The instance of affected litters would have been incredibly rare and would almost always have occurred within instances of inbreeding (breeding close relatives together). If this had continued then there was a chance that the gene (through luck in the selection of breeding stock) could have disappeared from the Rottweiler breeding population.

However, in the 1980’s something changed within the gene pool. One of the carriers from this rare and little used bloodline seems to have produced at least two sons that went on to become popular sires. Many of their sons became popular sires too and the gene spread quickly within the population – this is known as the Popular Sire Syndrome. Still, in the first few generations after this event most of the JLPP affected litters would have been from inbreeding or line breeding and this could account for some instances of affected offspring being thought of as a by-product of breeding closely related dogs together.

Within the next 35 years the bloodlines that contained the original popular sires with the carrier gene became highly sought after and by 2017 nearly all bloodlines contain at least one link to those dogs. JLPP is a good example of how devastating the Popular Sire Syndrome can be to a population – not just in diversity, but, in health related issues as well. At present there is an estimated 18 – 20 % carrier rate in the Rottweiler breeding pool (based on data collected from different labs. In most cases more than 1500 dogs have been tested by each lab and the percentages are not expected to change by any significant degree). The instances of affected litters being produced has risen with the percentage of carriers within the population. However, the Rottweiler breed was very lucky that the BRT breeders had already funded research into having a test for the gene and that not only was it available but compatible with Rottweilers. If this had not been the case then JLPP may have had a devastating blow on the Rottweiler as a breed.

How will breeders contain the spread of JLPP within the gene pool?

Up until now the JLPP gene has been working as an ordinary gene in any population would - with each passing generation of successful (popular) breeders who carry the gene the instance of that gene will rise within the population. That is what began to happen in the 1980’s when the gene started to spread very quickly. However, one should note that it took more than 35 years to reach the current point of 18-20% of the population. If this gene had remained hidden or unidentified then the instance of the gene within the population would have increased further, provided that those carrying the gene remained successful (popular) breeders.

However, selective breeding changes the dynamics of population genetics. The JLPP gene (now that it has been identified and can be controlled) will no longer act in the same manner as before. Breeders will always choose the clear puppy over the carrier when there is little difference between puppies. Most litters will give the breeder choice. For example: In a litter of 10 puppies there may be 6 girls. Out of those 6 girls 3 are considered to be potentially show quality. One puppy is slightly better than the other 2, but, is a carrier. The other 2 are clear. The breeder chooses one of the clears as the carrier is only slightly better than the other 2 (let’s say the pup's tan colouration is slightly deeper and the other two pups have good colouration). If, however, there are only 3 pups in the litter and only 2 are girls then the choice becomes harder. What happens if the other pup has a white patch? Or there is a marked difference in type/quality? If the best pup in this litter is a carrier then the breeder will/may choose the carrier. Regardless, in most instances the pup kept will be a clear. No breeder will keep a carrier simply to keep one. It makes finding potential suitors harder and the breeder may not have the use of the best dog for their bitch because of her carrier status. With these limitations in mind most breeders are going to choose the clear and the instance of the JLPP gene will fall. More than likely it will be gone or almost gone from the breeding pool within 3 generations.

Why is it important to test a dog if the JLPP status of both parents is clear?

It's important to test all breeding stock - even those from a clear - clear mating for 2 reasons. Firstly it helps with statistical data. If all breeding stock are tested then we can monitor the percentage of carriers over several generations to determine how well the progress of eliminating the gene is going.

Secondly there is such a thing as a false reading. While this is extremely rare it can happen. If there was a false reading stating that a dog was clear and its offspring was just assumed to be clear then any carriers that this dog would produce would remain hidden to disastrous effect. Getting all breeding stock tested regardless of the status of the parents is the smartest and most reliable course of action to eliminate this gene in the Rottweiler.

Who is to blame?

Up until early 2017, JLPP in Rottweilers was largely unknown. Most breeders, vets and specialists knew nothing about the disease and most instances of JLPP were misdiagnosed. It wasn’t until 2014 that the disease was even discovered to exist in the Rottweiler. Indeed, until the ADRK made testing compulsory in late 2016, most breeders had never even heard of JLPP. When it became apparent that JLPP was far more prevalent in the Rottweiler gene pool then anyone had thought, many breeders across the world began to test their breeding stock and a clear picture began to form.

The spread of this gene cannot be blamed on any one breeder or dog. At the time, the existence of the gene was unknown and the spread of the gene was a natural result of breeding high quality dogs that other people valued and wanted in their bloodlines. It is perhaps a lesson in the value of diverse breeding programs and the dangers of over using particular bloodlines to the detriment of the diversity of the gene pool, but, nothing more.

However, that being said, anyone who now refuses to test their breeding stock for this disease to ensure that they are not producing JLPP affected puppies can and should be held accountable for their actions. There is no longer any excuse for producing puppies that will die from this disease.