Primary Lens Luxation (PLL)

What is Primary Lens Luxation (PLL)?
Primary Lens Luxation, or PLL for short, is an easily recognizable, painful, and blinding hereditary defect in a wide variety of dog breeds, particularly in the terriers and terrier type. In affected dogs, the bands with which the lens is fixed degenerate. When the lens is eventually no longer in the correct position, the dog will go blind.
The symptoms develop at a young age. Within a few hours to a few weeks after birth, the characteristics associated with these DNA variants can be observed.

PLL research
A DNA test is available at a number of laboratories to investigate whether a dog has this disease. We use blood EDTA for this test, this is taken from the vet and sent directly to the laboratory.

Results

Free
The dog has two healthy alleles.
This animal will not develop any abnormalities when used in breeding and cannot pass the abnormality on to the next generation.
Carrier
The dog has a healthy allele and a defective allele.
The animal will pass on the mutant (defective) allele to half of its offspring.
Sufferer
The dog has two defective alleles.
Sufferers pass on the abnormal allele to all their next-generation offspring and develop symptoms associated with the disease.

Inheritance
This characteristic is inherited in an autosomal, recessive manner. This means that an animal can be free (homozygous normal), sufferer (deviating homozygous) or carrier (heterozygous).
Carriers can spread the mutation in the population without having the symptoms themselves. This makes it particularly important to detect carriers to prevent spreading.

Treatment
There is no known treatment for this disease.

PLL and breeding
It is recommended to breed with animals that do not have the mutation.
In order not to compromise genetic diversity, it is recommended to use breeding technically valuable animals that carry the mutation for breeding, but only in combination with animals that do not have the mutation. It is therefore recommended to identify the genetic carriers among the offspring through the DNA test.

To prevent puppies from being born with this condition, all parents will be tested on this before breeding.

Larynx anatomy
The Larynx (or voice box) consists of a cartilage structure covered with muscle tissue (8 muscles) and connects the pharynx to the windpipe. The larynx also contains the vocal cords and is covered by a movable valve-like structure called epiglottis. The epiglottis closes the trachea when the dog eats and drinks to prevent food or water from entering the trachea.

The larynx itself can also close to prevent food debris from entering the trachea.
The larynx also regulates the airflow in the trachea during breathing. The closing function is very important and 7 of the 8 muscles ensure closing of the larynx during eating and drinking. Only 1 muscle opens the larynx during breathing.

Laryngeal
paralysis Laryngeal paralysis means a disturbance in the laryngeal function. With paresis (sagging) or paralysis (paralysis) of the larynx, the dog is no longer able to open the voice gap properly, so that insufficient oxygen can be absorbed when inhaled. An obstruction has developed in the airway. This causes unpleasant symptoms: a changed voice, gagging or coughing during eating and drinking, decreased stamina during exertion, too clear breath sounds (like a seal), difficulty breathing, blue discoloration of the tongue or even fainting. There may then be a condition called laryngeal paralysis or vocal slit narrowing.

The cause of the malfunction of the voice cleft is due to the malfunctioning of the muscles of the larynx, the nerves that control the muscles, or a combination of both conditions. It can in principle occur in all breeds, but it is most commonly found in somewhat older dogs of the larger breeds. Usually the cause is unknown (idiopathic).

Fortunately, it has been possible to find out by means of a DNA test since 2019 whether the dog carries this condition. There are 3 possible results: Clear / Carrier / Suffer

Breeding
The transfer of LP to the offspring is:
Clear x Clear = 100% Clear
Clear x Carrier = 50% Clear and 50% Career
Carier x Carier = 25% Clear and 50% Carrier and 25% Affected

Information source LABOKLIN NV *

To prevent puppies from being born with this condition, all parent animals will be tested on this before breeding.

What exactly is LAD?
In short, simple: LAD is a very nasty congenital condition that ultimately leads to the death of the dog. It occurs with both the Standard and the Miniature Bull Terrier. There are veterinarians who say that they have seen it in other breeds, but no official records can be found.

Most striking about dogs with LAD are the many skin infections. These are somewhat similar to the inflammation seen in people with acrodermatitis enteropathica, among others. In humans, this is caused by the inability to properly absorb zinc. Because of this, dogs with LAD are also called Zincertjes (with a c, in English).

In humans, the symptoms can be remedied by giving a lot of zinc, with the Bull Terrier that is not possible.

LAD from head to butt & inside out:
A dog with LAD is remarkably small, often half the size of their litter companions. In addition to smaller, they look thin. Once older they look stunted.

Eating is a bit difficult due to a raised palate. At first they seem to drink well, but when you weigh them before and after the meal they seem to have eaten (almost) nothing. The transition to a porridge often works reasonably well, but if the food becomes a bit more solid, it will stick to the raised palate. It also talks about swallowing problems and a shortened tongue.

It is also difficult to keep the body at the right temperature for LAD dogs.

Dogs with LAD are born with a normal coat color. After a few weeks it slowly starts to fade. Not to be confused with dogs born with a faded coat due to a “fading gene”. There are reports that in “good periods” the coloring increases slightly again.

Crusty inflammation develops on the feet and head and the soles of the feet are hard and cracked. The excessive development of this "hard skin", also called keratin, causes the legs to look somewhat deformed. In places where there is a lot of frictional contact, such as the elbows and heels, inflammation of hair roots is seen. Due to the reduced functioning of the immune system, other skin infections often occur here. Impaired vision and other eye problems. Dogs with LAD seem to look with closed eyes. The third eyelid may protrude slightly and they may have reduced vision.

In terms of behavior, they are reported to be aggressive and growl directly instead of barking. People who have dogs with LAD report that the growl is not always meant to be angry, but rather is a different way of communicating. The response can be quite fierce and out of proportion.

Just born you see absolutely nothing, absolutely nothing. Over time, the stunted growth becomes somewhat noticeable, when you switch to solid food you see a somewhat difficult eater and a coat that slowly appears to become paler (which is difficult with a white one)…. It usually was. The first truly characteristic symptoms, such as persistent skin inflammation, do not appear until the puppy is between 4 and 12 weeks old. Not always, not all symptoms & not always as serious. There are dogs with LAD that are less severely affected and dogs that show very serious symptoms. Not all symptoms have to show.

Living in the puppy are a few moments when a handsome attack on the immune system takes place. Grafting, deworming and of course the move to the new owner. This move is already quite a condition for healthy puppies, let alone for a dog with LAD. It can therefore happen that the characteristic inflammations only start at one of these moments, including the move. This can cause a lot of stress and misunderstanding between the breeder and the ultimate owner. Many dogs with LAD are put to sleep at a young age.

Because the condition is not well known by many veterinarians and until recently the diagnosis could only be made by adding up the symptoms, it was sometimes difficult to get the correct diagnosis. The fact that the Bull Terrier is known with allergies, stomach / intestinal problems and atopic dermatitis

Breeding:
The transfer of LAD to the offspring is:

Clear x Clear = 100% Clear
Clear x Carrier = 50% Clear and 50% Carrier
Carier x Carier = 25% Clear and 50% Carrier and 25% Suffer

information source LABOKLIN NV *

Om To prevent puppies from being born with this condition, all parents will be tested on this before breeding.