Spinocerebellar disorders are often neurodegenerative diseases. They constitute a large group of rare disorders characterized by various manifestations of ataxia, in some cases with selective dysfunction of other systems (e.g. the corticospinal tract). Damage to the corticospinal tract is the key symptom of some other neurodegenerative disorders, namely hereditary spastic paraplegia and primary lateral sclerosis. The ability to diagnose these various disorders has improved enormously thanks to the rapid developments in DNA testing. The treatment is currently still purely symptomatic. Rather than focusing on all manner of rare disorders, this chapter is primarily intended to spotlight developments in the field of neurodegenerative disorders, as well as the various ways in which these can be regarded from a clinical and genetic point of view. By way of an introduction, there is a general discussion of neurodegenerative disorders, which also extends to other chapters (sect. 26.1). This is followed by a classification of spinocerebellar disorders, in which both hereditary and non-hereditary forms are described (sect. 26.2). The section after that deals with the autosomal dominant, autosomal recessive, and non-hereditary forms respectively, linking clinical and genetic aspects where possible (sect. 26.3). The final topic is another neurodegenerative disorder, that mainly affects the spinal cord – hereditary spastic paraplegia (sect. 26.4).
