Hereditary ataxia is a general term for a group of neurodegenerative diseases with ataxia as the main manifestation and a familial tendency. The causes of most of them are unknown. The lesions mainly involve the spinal cord, cerebellum and brainstem, so it is also called spinocerebellar-brainstem degeneration. Other parts such as spinal nerves, cranial nerves, basal ganglia, thalamus and cerebral cortex can be affected. It is often accompanied by abnormalities of other systems, such as bones, eyes, heart, endocrine and skin. Due to the differences in the degree of focal degeneration damage, age of onset and inheritance mode, this type of disease manifests itself clinically in many types or syndromes, with at least 60 types. There are often overlapping symptoms between the various types, and there is no ideal classification method so far.