Clinical signs are present by 3 months of age, and the condition rapidly progresses. Signs include generalized cerebellar ataxia, tremors, and failure to thrive. Cerebellar shrinkage is detectable through MRI. Due to the fast disease progression, euthanasia is usually elected within 1 month of onset. If performed, pathological and histological examinations yield evidence of cerebellum-restricted neurodegeneration with marked loss of Purkinje cells in the cerebellar cortex and secondary changes in other cortical layers.

Affected puppies are usually euthanized on welfare grounds because of the severity of the condition.

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. However, carriers with one copy can show clinical signs. Breeding with clear dogs will eliminate the risk of producing puppies that show clinical signs due to this disease mutation. However in breeds with a high frequency of this mutation, use of carriers may be needed to maintain breed diversity whilst gradually removing the disease mutation from the breed population. Breeding a carrier dog with a clear dog will produce a litter of about half clear puppies and half carrier puppies. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the Early-Onset Cerebellar Ataxia mutation could develop due to a different genetic or clinical cause.