Neurologische ziektes bij het Kooikerhondje

The Kooiker dog, officially called ‘het Nederlands Kooikerhondje’ and hereafter called Kooiker dog, is a small Spaniel-type breed historically used to catch ducks in a decoy [1, 2]. Although the breed dates most likely back to the 16th century [3] it faced extinction in the 20th century as it had lost its purpose. However, shortly after World War II the breed was re-established by Baroness van Hardenbroek van Ammerstol by carefully selecting a small number of Kooiker dogs. Although she was able to retrieve 30 Kooiker dogs only 10 dogs were used to re-establish the breed [1, 4, 5]. The breed gained popularity and currently it can be found throughout Europe, the USA and Japan. The total number of Kooiker dogs born between 1942 and 2022 is approximately 35000.

When using such a small number of dogs to re-establish a breed there is an increased risk of genetic disorders. The Dutch breeders association (Vereniging Het Nederlandse Kooikerhondje - VNHK), aware of these risks, promoted the use of all dogs for breeding to limit inbreeding and health records were kept in a club register that contains info of all Kooiker dogs born across the globe [4]. Despite this, the first hereditary disease identified in the breed was hereditary necrotizing myelopathy described in 1993 by Mandigers et al., [1] and von Willebrand Factor Deficiency in 1994. Our group, the Expertise Centre of Genetics, found both the causative mutation for von Willebrand Factor Deficiency as well as the causative mutation of hereditary necrotizing myelopathy [6-8]. Hence neither of these two diseases still exist within this breed.

Currently we are working on a disease first noted in 1970: Kooiker dogs having neuromuscular problems [4]. The Kooikerdogs are presented with clinical signs of exercise intolerance, a stiff gait, cervical ventroflexion, sialorrhea and difficulty eating. We have described in detail the clinical and pathological presentation of this disease, polymyositis, in the international journal 'Animals' [9].
We already have found the causative mutation (publication expected early 2024) but we are now working on:

  1. Exact immunohistochemistry (publication expected early 2024)
  2. Effect of various treatments (publication expected mid 2024)
  3. MRI features of Polymyositis (publication expected mid 2024)

Kooikerdogs with polymyositis are still welcome for clinical workup as well as treatment. If you want to support our research this can be done using the following link. The link will transfer you to our foundation collecting financial support to enable this research.

Many thanks

Dr. Paul Mandigers
Project leader


  1. Mandigers PJ, van Nes JJ, Knol BW, Ubbink GJ, Gruys E. Hereditary Kooiker dog ataxia. Tijdschrift voor diergeneeskunde. 1993;118 Suppl 1:65S. Epub 1993/03/01. PubMed PMID: 8480326.
  2. Mandigers PJ, Van Nes JJ, Knol BW, Ubbink GJ, Gruys E. Hereditary necrotising myelopathy in Kooiker dogs. Research in veterinary science. 1993;54(1):118-23. PubMed PMID: 8434139.
  3. Stipriaan Rv. De Zwijger. Het leven van Willem van Oranje. Amsterdam, The Netherlands: Querido; 2021 16-11-2021.
  4. Snels C. Clubregister van de vereniging Het Nederlandse Kooikerhondje. VHNK, editor. Westendorp, The Netherlands: VHNK; 2022 1962-2022. 1533 p.
  5. Mandigers PJ, Ubbink GJ, Vanden Broek J, Bouw J. Relationship between litter size and other reproductive traits in the Dutch Kooiker dog. The Veterinary quarterly. 1994;16(4):229-32. Epub 1994/12/01. PubMed PMID: 7740749.
  6. Mandigers PJJ, Stehling O, Vos-Loohuis M, Steenbeek FGv, Lill R, Leegwater PAJ. A novel IBA57 variant is associated with mitochondrial iron-sulfur protein deficiency and necrotizing myelopathy in dogs. Frontiers in Genetics. 2023:10.
  7. Slappendel RJ, Beijer EG, van Leeuwen M. Type III von Willebrand's disease in Dutch kooiker dogs. The Veterinary quarterly. 1998;20(3):93-7. Epub 1998/07/31. PubMed PMID: 9684296.
  8. van Oost BA, Versteeg SA, Slappendel RJ. DNA testing for type III von Willebrand disease in Dutch Kooiker dogs. Journal of veterinary internal medicine / American College of Veterinary Internal Medicine. 2004;18(3):282-8. Epub 2004/06/11. PubMed PMID: 15188812.
  9. Opmeer Y, Grinwis GCM, Shelton GD, Rosati M, Alf V, Fieten H, et al. An Inflammatory Myopathy in the Dutch Kooiker Dog. Animals (Basel). 2023;13(9). Epub 20230429. PubMed PMID: 37174546; PubMed Central PMCID: PMCPMC10177195.