Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Spinocerebellar ataxia 15 ?
    ### Response:
    Spinocerebellar ataxia 15 (SCA15) is a neurological condition characterized by slowly progressive gait and limb ataxia, often in combination with eye movement abnormalities and  balance, speech and swallowing difficulties. The onset of symptoms typically occurs between ages 7 and 66 years.
    