One of the toy dog breeds that can be affected by Chiari malformation is Cavalier King Charles Spaniel……Mylo’s breed. Fortunately, vets had a good inspection of Mylo when he was a puppy and stated that this will not affect Mylo in his later life.
“A new study from the University of Surrey, published today in the journal PLOS One, has identified the specific effect Chiari malformation has on the shape of a dog’s skull and brain. This condition has become prevalent as a result of selective breeding and affects many toy dog breeds which have been bred to look more doll-like, including Griffon Bruxellois, Cavalier King Charles Spaniels, Chihuahuas and their crosses.
Researchers took brain, skull and vertebrae measurements of 155 Griffon Bruxellois and compared dogs affected by the condition, with normal Griffons. They discovered that Griffons with the disease had taller foreheads and that it had also caused the shape of the brain to change, with severely affected animals having their cerebellum pushed underneath the main part of the brain.”