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Chiari malformation and syringomyelia are well-known neurological disorders in toy breeds. PhD candidate , supervised by associate professors Paul Mandigers and Hille Fieten and professor Hans Kooistra, investigated these conditions in Pomeranians. His research demonstrated the behavioural signs linked to Chiari malformation and syringomyelia and identified anatomical features that increase the risk of developing them. Santifort defended his thesis at Utrecht ľ¹Ï¸£ÀûÓ°ÊÓ on 11 September.

Earlier studies showed that over 60 percent of Pomeranians have Chiari malformation and that 25 percent suffer from mild to severe syringomyelia. Both conditions are also , such as the Cavalier King Charles Spaniel, Griffon, and Chihuahua. They can occur independently and may appear as early as one year of age, or only later, around five years.

Because the diseases are not visible externally, early and accurate diagnosis is challenging. Breeders who wish to prevent transmission of these hereditary conditions cannot rely on outward signs and depend on MRI screening. Santifort’s findings provide owners, veterinarians, and breeders with valuable tools for recognising the diseases and improving breeding decisions.

Repeated observation of such behaviours should prompt timely investigation, as they may indicate the presence of these conditions

Behavioural characteristics

Santifort's research looked at behavioural symptoms in dogs with Chiari malformation or syringomyelia. Owners of Pomeranians were asked to report their observations. This study shows that dogs with Chiari malformation or syringomyelia frequently displayed signs such as excessive vocalisation, head shaking, paw licking or biting, spontaneous pain attacks, air licking, and scratching. Dogs showing these behaviours were four to five times more likely to have abnormalities on MRI than dogs without such complaints. 

These behaviours can be key warning signs for veterinarians and owners. Santifort advises that repeated observation of such behaviours should prompt timely investigation, as they may indicate the presence of these conditions.

Anatomical characteristics

In addition to behavioural symptoms, the team examined the anatomy of Pomeranians with Chiari malformation and syringomyelia. This revealed that dogs with syringomyelia often have specific characteristics, including a shorter skull base and altered contents of the cranial cavity. Although not all questions have been answered yet, there is a clear relationship with the size of the dog: the smaller the Pomeranian, the greater the risk of syringomyelia. Pomeranians weighing less than 2.5 kilograms are six times more likely to develop syringomyelia than heavier dogs. MRI and CT scans, alongside physical measurements, supported these findings.

The disease is often progressive, with symptoms worsening or appearing later in life

Effective breeding strategies

Santifort followed a smaller group of Pomeranians with syringomyelia over time. The study revealed that the disease is often progressive, with symptoms worsening or appearing later in life. This highlights the importance of carefully timed MRI screenings for breeding animals. Screening too early can give false reassurance, while delaying screening until later in life helps ensure that only unaffected dogs are included in breeding programmes. This approach supports more effective breeding strategies against syringomyelia. Meanwhile, researchers at the Expertise Center for Genetic Veterinary Medicine at Utrecht ľ¹Ï¸£ÀûÓ°ÊÓ are studying the genetic background of Chiari malformation and syringomyelia. In the future, this may enable the development of a DNA test to aid breeders in selecting healthy dogs.

The insight that syringomyelia can progress over time underscores the need for effective treatments. Two studies have now been conducted to investigate a potentially better medication for Chiari malformation and syringomyelia and how we can .