One of the more heartbreaking disorders that can strike your dog is an inherited brain disorder known as cerebellar abiotrophy. In this condition there is premature aging and deterioration of the cerebellum, which is the part of the brain that controls movement and coordination. In most animals with this condition, the cerebellum matures normally before the puppy is born, but then specific cells in the cerebellum, known as Purkinje cells, deteriorate steadily after birth. Occasionally cells in other areas of the brain are affected as well.
Cerebellar abiotrophy is an inherited disorder which is carried through recessive genes. The sole exception are English Pointers. These animals are subject to a different form of the disease that's carried through dominant genes.
The problem causes poor coordination and balance in the affected animal, and there are several varieties that can strike. A very rare type is known as neonatal cerebellar abiotrophy, in which the brain cells begin degenerating before birth. Puppies with this disorder will display symptoms immediately after birth and/or when they first begin to walk. This form often strikes Beagles and Samoyeds.
Postnatal cerebellar abiotrophy appears when cells are normal at birth, but begin to degenerate afterward. How soon this process begins and how fast it progresses varies widely, depending on the breed of dog affected. Symptoms usually appear around six to 12 weeks of age, and the condition worsens rapidly in only a few weeks. Dogs with cerebellar abiotrophy will have poor balance and stand with their feet wide apart. They usually have a stiff or high-stepping gait and seem unaware of where their feet are located. (Many dogs will stand or walk with a foot turned under.) They also display head and/or body tremors, and may become unable to climb stairs or stand without support. The dog is mentally alert, but the as the disease progresses it frequently causes confusion, aggression, incontinence, blindness and seizures. Breeds most often affected with the postnatal form are Australian Kelpies, Border Collies and Labrador Retrievers.
Other breeds are affected somewhat differently by the condition. Airdeales usually display symptoms around 12 weeks of age, and in these animals the disease progresses slowly. Signs show up by six months of age in Bern Running Dogs, Bernese Mountain Dogs and German Shepherds. Other affected breeds include: Brittany Spaniels, Collies, Gordon Setters, Kelpie Blue Terriers and Miniature Poodles.
Veterinarians make a determination of cerebellar abiotrophy by observing the dog's symptoms and using a variety of tests, including MRI, especially if the dog is of a breed that is known to carry the defective gene. However, a definite diagnosis can only be made by examining brain tissue after the animal is deceased. Sadly, there is no effective treatment for this condition, and at some point the affected animal will have to be euthanized.
Dogs with cerebellar abiotrophy obviously should not be bred, and neither should their parents or siblings. In the case of x-linked cerebellar ataxia (the form of the disease that strikes English Pointers), only male puppies are affected; although the mother is the carrier of the affected gene.