July 06 2022 18:54:25 

Health Matters
Health Matters

Syringomyelia and Chiari-like Malformation (CMSM) is a recent hereditary condition first identified in the Cavalier King Charles Spaniel. It has now been diagnosed in other toy breeds including the Griffon Bruxellois. The condition is of a growing concern to breeders and dog owners alike.

SYRINGOMYELIA (SM) is where the normal flow of cerebrospinal fluid in the brain and the spinal cord is altered or blocked so that cavities develop, called syrinxes. These cavaties/syrinxes filled with the cerebrospinal fluid can cause damage to the spinal cord and function of the nervous system. A syrinx can develop as young as 3 months or more slowly over a period of years. There is no cure, the condition can be managed through medical intervention with high strength analgesics or corticosteroids for pain management and medication to reduce cerebrospinal fluid production

CHIARI-LIKE MALFORMATION (CM) is a malformation or mismatch between the skull size and brain size. In CM the skull is too small and the brain is too big, which leads to the brain being squashed and pushed out the back of the dog’s skull (foramen magnum) into the vertebral canal. This obstructs the flow of cerebrospinal fluid in and out of the brain. CM can be extremely painful and surgery may be an option to relieve pain and suffering and improve the flow of cerebrospinal fluid. Chiari-like malformation is a birth defect where the dog is born with the condition.

CMSM is rarely fatal but can be increasingly painful and debilitating. Suffering is such that affected dogs may need surgery or early euthanasia. Early diagnosis and treatment can help in slowing the progression of the disease. The severity of syringomyelia relates to the width and asymmetry of the syrinx

Symptoms can vary from dog to dog and not all dogs exhibit all of the same symptoms. Though symptoms may be unnoticeable in some dogs other dogs are quite affected but vary in the way the outward symptoms show. Dogs are usually diagnosed upwards from the age of 6 months. Due to the progressive nature of the condition symptoms may not show themselves until around the age of three or four years or even later as a dog ages and matures. Some badly affected dogs exhibit symptoms from a very young age.

Symptoms include pain or sensitivity to touch around the neck region including ears and shoulders. Scratching in the air without body contact or scratching around the regions of neck, shoulders, head, face and ears .Biting hind quarters or chewing front paws. Sudden yelping or crying out for no obvious reason. Limb weakness, particularly hind legs. Rubbing of eyes, ears, face on to the ground or rubbing on to paws. Slowing down of movement or reluctance to walk due to pain. Reluctance or hesitation to jump on to furniture or climb stairs. Random screaming because of pain which may lead to aggressive behaviour particularly to other dogs. Curving of the spine leading to scoliosis. Seizures.

All symptoms need thorough investigations by an expert (neurologist ) to rule out other causes. Some symptoms are common to other diseases and conditions. A MRI scan is the only conclusive way of confirming a diagnosis of syringomyelia and chiari-like malformation.

The nature of syringomyelia means that a dog may not show any symptoms of the condition but are carriers of CMSM and pass on these genes to their litters. Subsequent litters of pups may show symptoms from an early age or be carriers themselves. Due to the progressive nature and late onset of SM dogs may have sired or bred a number of litters before it is known that they syringomyelia.

For indepth information on all aspects of CMSM check out Dr Clare Rusbridge,BVMS PhD DipECVN MRCVS, very informative website. http:www.veterinaryneurologist.co.uk

Chiari-like Malformation and Syringomyelia Research

Research into understanding various aspects of CM/SM has been carried out by several researchers worldwide. In the UK Dr Clare Rusbridge is a leading researcher into chiari-like malformation (CM) and syringomyelia (SM) in cavaliers. In Canada Dr Zoha Kibar with Dr Guy Rouleau is undertaking the genome DNA research. In the USA Dr Simon Platt is researching CM/SM in the Griffon Bruxellois (Brussels Griffon).

Since 2004 the CM/SM genome research has been underway. The International Research Team believe CM/SM is polygenetic. This indicates that CM/SM is controlled by different genes which may affect one another in particular ways. There appears to be separate genes for CM and SM. Finding the gene’s involved in this complex trait is very challenging because studies suggest some environmental influences are also involved. Another problem is the 'late onset' nature of SM (it is a progressive condition and dogs may show no signs for several years).

The Genome Research in Canine CM/SM is currently lead by Dr Zoha Kibar and Dr Clare Rusbridge. The mammoth task of finding the genes was initiated by Dr Rusbridge and Dr Guy Rouleau whose laboratory is at CHU Sainte Justine Research Centre in Montreal Canada. The DNA collection has been ongoing since 2004 and many individual owners and veterinarians worldwide have contributed, funding the MRIs mostly themselves. Additional CKCS DNA samples have been provided by North Carolina University and Guelph University in conjunction with their own investigations into CM/SM.

In 2010 Genome wide linkage studies identifies a novel locus for syringomyelia associated with chiari-like malformation in the Cavalier King Charles Spaniel. This states that researchers have identified an area on the cavalier genome that is highly likely to be the genetic site specifically for SM, and that this area is unaffected in clear dogs. In the Cavalier King Charles Spaniel the continuing work on this project is to hone in on the fine mapping of the genes, to determine in as much detail as possible, exactly where this is happening.

CMSM in Griffon Bruxellois - research in this breed initially investigated chairi-like malformation because, unlike 99% of Cavaliers, Griffons do not all have chiari-like malformation. A radiograph study of the skull identified abnormalities and this study underpinned an investigation at Georgia University ‘The MRI, Clinicopathology and Prevalence’ funded in part by the American Kennel Club Canine Health Foundation. The USA team is led by leading researcher Dr Simon Platt and in collaboration with Dr Rusbridge and Dr Kibar, the project will also provide additional DNA and phenotypic information to investigate chiari-like malformation . The team have already identified the part of the chromosome where the gene/s are located.

Syringomyelia Research Update May 2014

The Griffon Bruxellois Club has been working closely with a number of Researchers specialising in Chiari Like Malformation (CM) and Syringomyelia (SM).

The Club has helped to fund MRI scans and encouraged breeders and owners of Griffons to get their dogs scanned and at the same time submit DNA so that the areas affected in the Canine Genome can be identified with the aim of eventually being able to identify those dogs that are at risk of developing CM/SM from a genetic test. The disease is complex and thought to be Polygenic with a number of mutations on different genes being responsible for causing the disease.

There have been 2 very important pieces of Research published recently. These Papers are specific to the Griffon Bruxellois and as such we are very grateful to the researchers who put so much time and effort into publishing them.

Quantitative trait loci (QTL) study identifies novel genomic regions associated to Chiari-Like Malformation in Griffon Bruxellois Dogs

Philippe Lemay, Susan P. Knowler, Samir Bouasker, Yohann Nedelec, Simon Platt, Courtnay Freeman, Georgina Child, Luis B. Barreiro, Guy A. Rouleau, Clare Rusbridge, Zoha Kibar.
Published April 2014
DOI: 10.1371/jpurnal.pone.0089816


Quantative Analysis of Chiari-Like Malformation and Syringomyelia in the Griffon Bruxellois Dog
Susan P. Knowler, Angus K. McFadyen, Courtneay Freeman, Mark Kent, Simon R. Platt, Soha Kibar, Clare Rusbridge.
Published February 2014
DOI: 10.1371/jpurnal.pone.0088120


Other articles of interest are:

Chiari-Like Malformation in the Griffon Bruxellois
Clare Rusbridge, Susan P. Knowler, Lee Pieterse, A.K. McFadyen
Published online: August 2009
DOI: 10.1111/j.1748-5827.2009.00744.x


Grading for Chiari-Like Malformation and Syringomyelia

The Kennel Club (KC) and British Veterinary Association (BVA) have now put an official scheme in place to grade the presence and/or severity of Chiari-Like Malformation (CM) and Syringomyelia (SM).

This involves an MRI scan of the dog's head and neck area. The dog will have to be sedated or anaesthetised in order to keep it still for the duration of the scan.

There are a number of veterinary centres in the UK that offer low cost scans for submission to the KC/BVA CMK/SM scheme. The cost is currently around £240.00 (inc VAT) for the scan and £100.00 (inc VAT) for the BVA grading.

Please see the BVA website for full details:


Results are published in the Breed Records Supplement published quarterly by the Kennel Club:


Also, available when you click on "health tests" for a specific dog on the Kennel Club's Mate Select database:


Breeding Recommendations

The BVA/KC has produced breeding recommendations for breeds that are affected by CM/SM:


When buying a puppy always ask whether the parents have been tested for CM/SM and if so then ask to see the certificates. The Club recommends that at least one parent be scanned and graded free of SM. Ideally both parents should be tested.

Club Scanning Scheme:
The GBC have a scheme in place for scanning Griffons. This scheme is open to UK members only and details about how a member qualifies for the scheme can be requested from our Breed Health Co-ordinator - Miss Jessica Gruninger.

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