Canine multiple system degeneration is a fatal, hereditary disease of dogs comparable to familial, juvenile-onset Parkinson's disease of people. Affected pups appear normal until about 4 months of age. Early signs include head shakeing when they try to focus on something. Other signs are exaggerated, goose-stepping movements (cerebellar ataxia). Age of onset from 4 months, progressing to severe signs of disease at 12-18 months, and most becoming incapacitated by 2 years. Affected dogs have difficulty even starting a movement and fall frequently. This is not to be confused with a form of cerebellar ataxia observed in the Kerry Blue Terriers. Signs of the disease can appear simmilar.