Three individuals of the Griffon Bruxellois breed from geographically well-spaced parts of the United Kingdom were presented with similar clinical signs. Two of them were male and one was female; they were 6, 5 and 3 years of age at the time of presentation. All three dogs showed an intermittent shifting lameness and two were periodically ataxic with mild proprioceptive deficits. The dogs were mildly hypertonic and hyperreflexic in the pelvic limbs. The most marked clinical feature was an intermittent pain reaction to palpation of the pelvic limbs. An apparent hyperaesthesia in the limbs resulted in periodic frantic biting and chewing without causing mutilation. There were no significant cranial nerve abnormalities.

Magnetic resonance imaging was carried out in all three dogs. The most dramatic finding was extensive syringomyelia. An extremely large syrinx was present in the spinal cord from the cervical spine to the lumbar intumescence. The syrinx in all three dogs was dorsally situated, unusually reaching the periphery of the dorsal funiculus. The sagittal MRI scans revealed caudal protrusion of the cerebellar vermis into the foramen magnum and there was bilateral distension of the lateral ventricles.

It is not surprising that this condition of the Griffon Bruxellois is similar to the well-known and frequently occurring Chiari malformation of the Cavalier King Charles Spaniel since the breeds are closely related in their origin. However, there are some important and significant differences in both the pathology and the clinical presentation. The position of the syrinx within the spinal cord of the Griffon contrasts with the central location in the Cavalier. Clinically the Griffon seems to show altered ambulation, not often a feature in the Cavalier. Certainly the likely inheritance of this condition in the Griffon and the small gene pool in the UK could have serious consequences for the breed.