Only 37% of Scanned Pomeranians Were Free of Both Conditions
If you own a Pomeranian — or are thinking about getting one — a large MRI study suggests Chiari-like malformation and syringomyelia are far more common in this breed than many owners realize. Research published in the journal Pets screened 999 Pomeranians and found that 57% showed signs of Chiari-like malformation and 31% showed syringomyelia, a fluid-filled cavity in the spinal cord. Only 37% of the dogs in the study were free of both conditions. The findings support a heritable (genetic) pattern in the breed and point toward MRI screening as a useful tool for responsible breeding decisions.
These are two of the most talked-about neurological conditions in small companion breeds. They don’t always cause obvious symptoms — and that’s partly what makes them tricky for owners and breeders to detect without imaging.
What Are Chiari-like Malformation and Syringomyelia?
Chiari-like malformation (CLM) is a structural problem where the back part of the skull is too small for the brain. This crowding pushes brain tissue toward the opening at the base of the skull. Think of it like trying to fit a slightly-too-large orange into a bag that’s just a little too small — the contents get squeezed toward the exit.
Syringomyelia (SM) often develops as a result of this crowding. When fluid movement around the brain and spinal cord is disrupted, it can form a fluid-filled pocket inside the spinal cord itself. This is called a syrinx (pronounced SY-rinks), and it can press on nerve tissue in a way that triggers pain, scratching at the neck or shoulders, or weakness in the limbs.
Both conditions are seen in many small and toy breeds, but Pomeranians appear to be among those with a notably high rate of occurrence. Because the skull shape is partly determined by genetics, these conditions tend to run in family lines — which is why the research team looked specifically at familial aggregation (the tendency of a trait to cluster among related animals).
How This Study Was Done
The researchers used MRI scans to look at a cohort of 999 Pomeranians. MRI (magnetic resonance imaging) is the gold standard for diagnosing CLM and SM because it gives detailed pictures of soft tissue — the brain, the fluid around it, and the spinal cord — that X-rays cannot show.
The team also looked at familial relationships between the dogs to see whether CLM and SM appeared more often in related animals than you’d expect by chance. Finding that pattern would suggest a genetic component is at work — not just random occurrence.
This was a retrospective study, meaning the researchers reviewed MRI data that had already been collected, rather than running a new experiment. That approach allows for large sample sizes but means the results reflect associations in the data, not direct proof of one thing leading to another.
What the Numbers Show
CLM and SM Were Extremely Common
The headline finding is striking: 57% of the 999 Pomeranians in the study showed Chiari-like malformation on MRI. 31% showed syringomyelia. And only 37% were free of both.
These figures suggest that most Pomeranians carry some degree of this structural issue — even if they are never formally diagnosed or never show any obvious symptoms during their lifetime. For breeders, that distinction matters. A dog that looks and acts healthy could still pass on the skull shape that is associated with these conditions in future litters.
A Pattern Consistent with Heritability
The study’s familial aggregation findings indicate that CLM and SM appear to cluster in related animals — a pattern consistent with a heritable trait. In plain terms, if a dog’s parents or close relatives had these conditions, that dog may be more likely to have them too. This supports what researchers and veterinary neurologists have suspected for years: skull shape in these small breeds is partly governed by genetics.
The research team concluded that MRI screening of breeding stock is a meaningful step toward managing this health issue in the Pomeranian population.
What Pomeranian Owners and Breeders Should Do Next
Symptoms Are Not Always Present
One of the most important takeaways is that many dogs with CLM or SM on MRI may not show any noticeable signs. When symptoms do appear, they can include:
- Persistent scratching at the neck, shoulder, or ear area — especially without making contact with the skin (called “phantom scratching” or “air scratching”)
- Yelping, crying, or sensitivity when touched around the head or neck
- Stumbling, wobbling, or weakness in the back legs
- Changes in posture — like carrying the head low or curving the body in an unusual way
- Apparent discomfort when wearing a collar
These signs range from mild and occasional to more frequent and disruptive. If your Pomeranian shows any of them, it’s worth raising with your vet — and asking whether a neurological evaluation or referral to a veterinary neurologist makes sense.
If You’re Buying or Breeding
If you are buying a Pomeranian puppy, it is worth asking the breeder whether the parents have had MRI screening for CLM and SM. Given the high rates found in this study, a breeder who screens their dogs is taking a meaningfully more informed approach to health management.
If you are a breeder, the study supports a strong case for MRI screening before pairing dogs. No screening program can eliminate these conditions entirely, but selecting breeding pairs with less severe or absent findings may help reduce the rate over generations.
Limitations of This Study
Because this was a retrospective cohort study, it describes patterns seen in a group of dogs whose MRI data was already available — it does not track the same dogs over time or measure whether any of them developed symptoms. The sample may not represent all Pomeranians worldwide, and the study notes that prevalence estimates should not automatically be applied to every Pomeranian population.
The study also does not establish which specific genes are involved, or how much any given dog’s risk changes based on its family history. That kind of work would require further genetic research. What the study does well is describe just how common these conditions appear to be in a large, MRI-screened group — which is itself valuable information for owners and breeders.
Why MRI Screening Matters for Pomeranian Breeding
A retrospective MRI study of 999 Pomeranians found that 57% showed Chiari-like malformation and 31% showed syringomyelia — with only 37% free of both. The familial pattern in the data is consistent with a heritable component, which supports the use of MRI screening in breeding dogs as a practical health management step.
If your Pomeranian scratches at the neck for no clear reason, seems sensitive around the head, or moves awkwardly at times, it’s worth mentioning to your vet. And if you’re planning to breed or buy a Pomeranian, asking about MRI health screening is a question worth adding to your list.
This article summarizes peer-reviewed research for educational purposes. Always consult with your veterinarian for personalized advice about your pet’s health and behavior.
