Parkinsonism & related disorders. Ataxias.

The ataxias are a group of progressive neurodegenerative disorders with ataxia as the leading symptom. Current classifications distinguish between hereditary and non-hereditary ataxias. The hereditary ataxias are further divided into the autosomal recessive ataxias, the most frequent of which is Friedreich's ataxia, and the autosomal dominant spinocerebellar ataxias. The non-hereditary ataxias are separated into the acquired ataxias, such as alcoholic cerebellar degeneration or paraneoplastic cerebellar degeneration, and the sporadic degenerative ataxias, such as multiple system atrophy or sporadic adult onset ataxia. The causative mutations of many hereditary ataxias have recently been identified. Therapies based on the knowledge of the underlying molecular pathogenesis are available for a number of ataxia disorders.