Genetic diseases

As with all dogs, hereditary disorders are also found in the kooikerhondje. Therefore, if one of the known hereditary disorders is found in previous generations, it is recommended to use as little inbreeding as possible when choosing breeding pairs.

Despite careful breeding – by the Association Breeding Regulations and with the help of the extensive documentation in the club register and ZooEasy – hereditary diseases can never be completely prevented.

A list of all known hereditary diseases in the kooikerhondje follows below.

Von Willebrand Disease (VWD)

A coagulation abnormality that causes bleeding (wounds, heat cycle) to last longer and to be life threatening.


In the Kooikerhondje, type 3 of this bleeding disorder is found (total absence of vWFactor). Often, gastrointestinal bleeding and urogenital bleeding occur.


Because DNA analysis is available since 1990, nowadays no affected animals are born within the VHNK population.
The VHNK offers a subsidy arrangement for members for VWD DNA testing at Utrecht University, provided it concerns a breeding animal.

Hereditary Necrotising Myelopathy (ENM)

Also known as ‘Kooikerverlamming’ (Kooiker paralysis)
Neurological disorder that affects the spinal cord white matter and leads to paralysis.


Affected dogs show symptoms from the age of 6 to 15 months. At first, the symptoms are mild: subtle coordination problems in the hind limbs. As the disorder advances, the progressive character will be emphasized. The dogs will ‘walk like a drunk’ in the rear end. At this time, the front will also show functioning problems and postural reactions are disturbed.
Affected animals are not in pain, but the disease is progressive and will lead to the dog’s death before it has reached the age of 2.


Since a few years DNA analysis is available, therefore nowadays no affected animals are born within the VHNK population.
The VHNK offers a subsidy arrangement for members for ENM DNA testing at Utrecht University, provided it concerns a breeding animal.

Patella luxation (PL)

In this disorder, the patella (knee cap) spontenaously dislocates or moves out of its normal location.


The Kooikerhondje is generally known with medial patella luxation, but in some cases the luxation is lateral. Severe forms (PL grade 2 and higher) cause instant lameness in the dog. Often they cry out of pain. The leg can not be used anymore. If the kneecap spontaneously moves back to its location, the dog will immediately be able to walk again.


15% of the tested dogs are mild cases (up to grade 1). About one time a year a severe case (grade 2 and more) is reported to the VHNK.

More information

The breeding policy (obligatory testing of all breeding animals / using a minimum of affected animals) makes sure the frequency of affected animals is kept at a low level.


Epilepsy is a disorder that causes dogs to have recurring seizures. Depending on the type of epilepsy, seizures can be described as recurring abnormal behaviour with a number of distinctive characteristics.
Epilepsy falls into two categories: primary epilepsy and secondary epilepsy. Primary epilepsy is the hereditary form.
In the veterinary world the definition of epilepsy requires that seizures, in any form, are recurrent.


Seizures can vary from small, atypical seizures, showing a broad variety of symptoms, to classic generalised seizures. Classic seizures generally occur within the age of 6 months to 5 years (not strictly!).
Seizures often happen at night or in early morning. The dog is unconscious and will fall on its side, has extended legs and moves its head over its back to the rear. After that, the dog will paddle with all four limbs. The seizure lasts between a couple of seconds and a couple of minutes. Sometimes a seizure can be predicted, most of the time it can’t.
The next stage is called the post-ictal period. This recovery can come in many forms and takes seconds to hours. Atypical seizures can limit themselves to abnormal muscular movement of paws or eyelids etc. and the dog is generally more conscious.


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 varied between 1 and 5 dogs a year.

More information

If a dog has over one seizure a month, it is recommended to start treatment. The usual medication prescribed is Phenobarbital. The response varies per dog. For more information we refer to a veterinarian or veterinary specialist in neurology.
The Information committee is willing to help finding more information or making contact with a veterinary specialist.


Autoimmune disease that causes chronic inflammation of one or more muscles, preventing them to function, which results in muscle weakness of the affected muscles. Myositis is a progressive disease with a very poor prognosis.
There are two groups. A group of relatively young dogs with mainly swallowing or eating problems. The second group of dogs is young to middle aged and has musculoskeletal problems or a combination with swallowing problems.


Depending on the location and kind of myositis, the most common symptoms are:

  • Reduced endurance
  • Muscle weakness
  • Swallowing problems
  • (Muscular) pain!
  • Fever
  • Total exhaustion, no more desire to play / walk.
  • Limping / stiffness
  • Walking with curved back
  • Drooling
  • Nausea
  • Anorexia / unwilling to eat

Because many symptoms are also indications of other diseases and often start as “vague complaints”, myositis will often be difficult to recognize / distinguish. To make a definitive diagnosis, additional blood tests for muscle enzymes (CPK / CK) are required, as well as an EMG, and a muscle biopsy for diagnosis and prognosis. Sometimes a swallowing film or scopy is needed.


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

More information

Treatment with medication is not always successful and the dog will die. At this moment research is done to the (genetic) cause of the disease in the kooiker breed and to the best treatment. For more information, please refer to Dr. P. Mandigers, working as a veterinary specialist at Evidensia Dierenziekenhuizen – department Arnhem

February 2017 – 10.000,- euro for research to polymyositis:
A donation of €10.000,- from the Deutsche Club für Kooikerhondje

August 2018 – How researcher and owner can help eachother. Read here: Polymyositis in Het Nederlandse Kooikerhondje

April 2019 – Some important steps forward in the research around polymyositis: Genotyping and Fit2Breed

November 2020 – Update polymyositis research and improvement in the treatment of polymyositis:
Mutation found

December 2022 – A Beta-version of Fit2Breed is now available:

Hereditary eye diseases

Within the Kooikerhondje population are only a few hereditary eye diseases, for instance:


Non congenital cataract, clouding of the lens inside the eye that can lead to blindness.
Because of restrictive breeding, the disorder is rarely seen in the breed.


An extra set of eyelashes, can be corrected surgically with a good prognosis.

A strict breeding policy makes sure that there are very few dogs with eye problems within the breed.

Kooikerhondje with health problems?
Contact the Information committee.