Question 1

Hereditary Necrotizing Myelopathy (ENM)

Accepted Answer

Also called ‘Kooikerverlamming’ (Kooiker Paralysis) or Leukodystrophy. It affects currently only 0.2% of the population approximately. ENM is a devastating disease that is still undergoing intense study. It is a recessive degenerative spinal disease.

The disease breaks out between the third and 12th month of life. Noticeable is a change in movement and muscle weakness that starts in the hind legs and progresses to the front legs until there is a complete paralysis of the body. Affected dogs die of asphyxiation if they are not euthanized. ENM is not painful and is not treatable. ENM is always lethal. After the first physical signs have started, Kooikers will die within 2 weeks to 11 months.

The cause is a destruction of the spinal cord. Post mortem examination has revealed a symmetrical bilateral necrotizing myelopathy with malacia in the ventral and dorsal white matter. The disease resembles the hereditary myelopathy seen in Afghan Hounds and the leucoencephalomyelopathy in Rottweilers. A research article from 1993 has concluded that it is an autosomal recessive disease. Currently, the only way to effectively eliminate ENM is to use preventative selection when choosing a sire and dam to breed. Your breeder should know about ENM!

A DNA blood test is available to screen for carrier status of ENM. The first analysis were performed beginning of July 2012 at the University of Utrecht. A dog that has been identified as carrying ENM does not necessarily mean that it is unhealthy. However the result does help with the selection of sire and dam. A carrier can be mated with a non-carrier or two non-carriers can be mated. Two carrier should NEVER be mated since their offspring can get the disease.

Please follow this link http://www.kooikerhondje.nl/en/fokkerij/data-vwd-enm-onderzoek/ (http://www.kooikerhondje.nl/en/fokkerij/data-vwd-enm-onderzoek/)to learn more about the test and research that has been done in The Netherlands.

Frequency
Since DNA analysis has been available, no affected animals have been born within the reported kooikerhondje population.

How to Test for ENM
Required for CHIC. 4 ml of blood in an EDTA tube or a cheek swab taken by your veterinarian sent to the University of Utrecht. Download the DNA test form at the top of this page for you and your veterinarian to fill out and send to the university in The Netherlands. ENM, vWD, and PM can be combined on one form and blood sample/cheek swab. Once the results from Utrecht have been received, fill out the OFA DNA test form here,(https://ofa.org/applications/) and send a copy of your results along with the form and payment to OFA.

Question 2

von Willebrand's Disease (vWD)

Accepted Answer

VWD is a hereditary clotting disorder caused by a defect or deficiency of a blood clotting protein, called von Willebrand Factor, protein that is required for platelet adhesion. This condition makes those afflicted likely to bleed abnormally and severely. This can lead to potentially life threatening consequences in situations such as accidental injuries, spaying, or neutering.

Frequency
Because DNA analysis has been available since 1990, no affected animals or carriers have been born within the reported kooikerhondje population the last 20 years. vWD is considered functionally extinct within the breed.

How to Test for vWD
Required for CHIC. 4 ml of blood in an EDTA tube or a cheek swab taken by your veterinarian sent to the University of Utrecht. Download the DNA test form at the top of this page for you and your veterinarian to fill out and send to the university in The Netherlands. ENM, vWD, and PM can be combined on one form and blood sample/cheek swab. Once the results from Utrecht have been received, fill out the OFA DNA test form here,(https://ofa.org/applications/) and send a copy of your results along with the form and payment to OFA.

Question 3

Polymyositis (PM)

Accepted Answer

It is assumed to be an autoimmune disease that causes chronic inflammation of one or more muscle groups resulting in loss of functionality and muscle weakness in the affected areas. Myositis is a progressive form of the disease with a very poor prognosis. We see two groups. The first  group consists of relatively young dogs with swallowing or eating problems. The second group consists of dogs that are young to middle aged and have more musculoskeletal problems and sometimes a combination with swallowing problems.  Depending on the location , the most common symptoms are:

• reduced endurance
 • muscle weakness
 • swallowing problems
 • fever
 • general fatigue
 • lack of drive to play or walk
 • lameness
 • stiffness
 • walking with curved back
 • salivation
 • vomiting
 • poor appetite

Because many symptoms are also features of other disorders, this condition is often difficult to recognize. If left undiagnosed, myositis is lethal; if diagnosed early, available treatments are immunosuppression and management with steroids. Kooikers with myositis seem to pass away at  3 or 4 years  after being diagnosed. Myositis in general can be hereditary or caused by infections, autoimmune diseases and toxins. It can be misdiagnosed as  Myasthenia Gravis, for example, by veterinarians. In order to  make a definitive diagnosis, a muscle biopsy by a qualified veterinarian is required. This tricky disease has been found more often in the Kooikerhondje population in recent years. We hope that current research in the Netherlands will give us a better understanding of the disease in the near future. There is no gender disposition which means males and females are affected equally.  It is difficult for general veterinarians that are not specialized to make the diagnosis.

The medical work-up includes an electro-myography (test to measure the muscle reaction after a stimulus is given) and a muscle biopsy (tissue sample taken from the affected muscle group). If the dog has difficulty swallowing, a bronchoscopy (internal exam with a camera visualizing the lungs and bronchial tree) as well. Before starting steroid therapy, the diagnosis of Polymyositis needs to be confirmed because steroids can alter test results. Dr. Paul J.J. Mandigers from the Veterinary Faculty at Utrecht University in The Netherlands thinks that Polymyositis in the Kooiker is a breed specific disease that is familial and hereditary. There is most likely a trigger that causes Polymyositis to break out. Dr. Mandigers is the leading world expert on PM. If your kooiker has been definitively diagnosed with PM, please contact him at p.j.j.mandigers@veterinair-neuroloog.nl (p.j.j.mandigers@veterinair-neuroloog.nl)to report your case and get the most up to date information on course of treatment for the disease. New developments in treatment are being made everyday.

Dr. Mandigers and Utrecht University have developed a partial genetic test for Polymyositis that can give a general risk assessment. This blood test can be run in conjunction with the DNA test for ENM and vWD, and detects the presence of 2 identifiable markers for PM. Dogs are given the designation of clear (WW - homozygous wildtype), carrier (WM - heterozygous), or affected (MM). Please note that any of the designations do not mean that your dog will or will not develop PM, they simply give an idea of the risk of your kooiker developing the disease.

Frequency
Unfortunately we see polymyositis more regularly at the moment. The frequency is around 1% of the population.

How to Test for PM
4 ml of blood in an EDTA tube or a cheek swab sent to the University of Utrecht. Download the DNA test form at the top of this page for you and your veterinarian to fill out and send to the university in The Netherlands. ENM, vWD, and PM can be combined on one form and blood sample/cheek swab.

Question 4

Patellar Luxation

Accepted Answer

A luxating patella occurs when the dog patella (kneecap), which normally sits on the groove of the femur (thigh bone), shifts out of alignment. It can occur in one, or both, of the hind legs.

When luxation of the patella occurs, your dog may experience intermittent hind limb "skipping," lameness, or a locking up of the limb at an odd angle. Once everything realigns, they return to normal as if nothing had happened. The Kooikerhondje is generally diagnosed with medial patellar luxation (kneecap slides to the inside of the knee), but in some cases the luxation is lateral (slides to the outside). Severe forms (PL grade 2 and higher) cause instant lameness in the dog.
 
A luxating patella in dogs can stem from a traumatic injury but more commonly is associated with joint or limb structure abnormalities, such as the groove of the femur where the kneecap sits being too shallow, or the area where the kneecap attaches to the shinbone (tibia) being displaced. These limb and joint changes result in an alteration of forces placed on the knee and, in turn, luxation of the patella.

This can be a hereditary defect, it can also be caused by malnutrition and over-exercise. Kooikerhondjes, as well as all mixed dogs or purebred, are susceptible to this structural defect. It is prevented through selective breeding and by use of a licensed canine orthopedic specialist’s diagnosis. The official evaluation normally occurs after 12 months, once most of the growing of the dog is done. However you may have your dog inspected earlier by a veterinarian for symptoms. A grade 1 luxation is considered acceptable for breeding. Grade 2 or higher should not be bred.

Frequency
15% of the tested dogs are mild cases (up to grade 1). About once a year a severe case (grade 2 and more) is reported to the VHNK (Dutch parent club).

How to test for Patellar Luxation
Required for CHIC. This test can be performed by your regular veterinarian. Find the form to take to your veterinarian here.(https://ofa.org/applications/) Mail the completed form and payment information to OFA.

Question 5

Eye Disease

Accepted Answer

As with patella luxation all dogs, mixed or purebred are susceptible to hereditary eye abnormalities and deformations such as cataracts, retinal dysplasia, or distichiasis (where the eye lash grows towards the lens). A cataract is typically a visual clouding of the lens inside the eye. The effect is seen as a blueish gray eye in stead of the normal brown.

Kooikers can only be examined by a board certified Veterinary Ophthalmologist for their CAER Eye Certification with OFA. Dogs used for breeding must carry a valid CAER certificate. A dog should be checked at age 12 months and then again before being bred if there is a time difference of more than 2 years.

Frequency
Occurrence of hereditary eye disease is rare.

How to test for Eye Disease
Required for CHIC. This test must be performed by a board certified veterinary ophthalmologist. The OFA form will be provided and mailed to OFA by your veterinary ophthalmologist. Find a board certified veterinary ophthalmologist in your area here.(https://www.acvo.org/ophthalmologist-search) OFA Eye Clinics are frequently available for testing at AKC shows, as well.

Question 6

Hip Dysplasia

Accepted Answer

Hip dysplasia is a common skeletal condition, often seen in large or giant breed dogs, although it can occur in our kooikerhondje as well. The hip joint functions as a ball and socket. In dogs with hip dysplasia, the ball and socket do not fit or develop properly, and they rub and grind instead of sliding smoothly. This results in deterioration over time and an eventual loss of function of the joint itself (i.e. loose hip socket to thighbone connection). Hip dysplasia can cause pain and lameness that can range from mild to crippling.

Some dogs begin to show the signs of hip dysplasia when they are young, others develop it in conjunction with osteoarthritis as they age.  Afflicted dogs may show:

• Decreased activity
 • Decreased range of motion
 • Difficulty or reluctance rising, umping, running or climbing stairs.
 • Lameness in the hind end
 • Swaying gait
 • Grating in the joint during movement
 • Loss of thigh muscle mass
 • Noticeable enlargement of the shoulder muscles as they compensate for the hind
 • Pain
 • Stiffness

Hip dysplasia can be caused by and inherited structural defect or environmental variables such as obesity and physical over-exertion. Like patella luxation, hip dysplaysia can be screened for. Ask a qualified veterinarian to x-ray your dog and submit results to OFA. Although hip dysplaysia is not a prevalent problem in the breed, it is always good to test for and to avoid mating Kooikers that have poor hip testing results.

How to test for Hip Dysplasia
Required for CHIC. The official OFA test for hip dysplasia cannot be performed before 2 years old. This test is a simple radiograph and can be performed by your regular veterinarian. Find the form to take to your veterinarian here.(https://ofa.org/applications/) Your vet will mail the form and your payment to OFA.

Question 7

Kidney Disease (renal dysplasia)

Accepted Answer

Renal dysplasia is defined as disorganized development of renal parenchyma that is due to abnormal differentiation. For definitive diagnosis of this category of conditions, microscopic observation of structures in the kidney that are inappropriate for the stage of development of the animal is required. The presence of immature glomeruli and tubules usually within radial bands adjacent to more normally developed tissue (i.e., asynchronous differentiation of nephrons) is the most consistent feature. Other findings indicative of renal dysplasia include persistent immature mesenchyme, persistent metanephric ducts, atypical tubular epithelial proliferation, and (albeit rare in dogs) dysontogenic metaplasia. Secondary changes that are commonly observed include compensatory hypertrophy and hyperplasia of glomerular tufts and tubules, interstitial fibrosis, tubulointerstititial nephritis, pyelonephritis, dystrophic mineralization, cystic glomerular atrophy, microcystic tubules, retention cysts, and glomerular lipidosis.

Renal dysplasia is reported in Kooikerhondjes and is diagnosed via ultrasound of the kidneys. Additionally, juvenile nephropathies with microscopic features of renal dysplasia have been reported in one or more unrelated dogs of so many different breeds that it seems likely that the disorder occurs at least sporadically in all breeds. The causes and pathogenesis of canine renal dysplasia are unknown. To date, data documenting the validity of genetic testing for renal dysplasia have not been published for any breed.

There is currently no genetic test available for kidney disease in canines.

Question 8

Epilepsy

Accepted Answer

Epilepsy is a brain disorder in which a dog has repeated seizures over time. Seizures are episodes of disturbed brain activity that cause changes in attention or behavior. An epileptic seizure is the clinical manifestation of abnormal brain activity in the cerebral cortex.

There are several types of seizures that are seen, and many times the dog owner isn’t even aware of the problem. Visible symptoms can include collapsing, jerking, stiffening, muscle twitching, loss of consciousness, drooling, chomping, tongue chewing, or foaming at the mouth. Dogs may fall to the side and make paddling motions with their legs. They sometimes poop or pee during the seizure

Epilepsy in canines is classified into two types: Idiopathic (also known as Primary) and Secondary. In Secondary epilepsy, a specific cause for the seizures is discovered, such as ingesting toxins or hypoglycemia.

Idiopathic epilepsy, which is diagnosed when there is no known cause for the condition is assumed to be inherited. This disease can only be avoided by careful selective breeding. A new research project has started in the Netherlands in order to find a gene marker for epilepsy but there are currently not enough cases and blood samples collected. Every breeder should follow breeding rules established by the VHNK when breeding with lines affected with epilepsy.

Frequency
Because of the special attention the VHNK is paying to this disorder, the number of affected dogs reported is declining. In recent years the number has varied between 1 and 5 dogs a year.

There is currently no genetic test for epilepsy in canines.

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