Spinocerebellar ataxia (SCA)

Spinocerebellar ataxia (SCA) is a progressing neurodegenerative hereditary group of diseases each of which is considered a separate disease. To date over 20 types of the disease are known. The spinocerebellar ataxia is an extremely heterogeneous group of neurodegenerative diseases. Before introduction of the molecular methods of testing into the general practice, no standard classification of these diseases existed and clearcut subdivision of the dominant spinocerebellar ataxias became possible thanks to DNA diagnostics and detection of the specific mutations in the examined patients (Illarioshkin SN et al., 1999; Rosenberg R., 1995; Stcvanin G. et al., 2000).

A general clinical characteristic of autosomal dominant spinocerebellar ataxias is a progressing disorder of movement coordination that manifests at an early or middle age, often in combination with other neurotological symptoms: pyramidal and extrapyramidal symptoms, ophthalmoplegia, polyneuropathia, dementia, optic nerve atrophy and retina degeneration (Ivanova-Smolenskaya IA et al., 1998, Rosenberg R., 1995). Usually, the degeneration of the cortex of both hemispheres, cerebellar vermis, inferior olive, nuclei and pons cerebelli as well as demyelinization of the white matter of the cerebellum are detected in the dominant spinocerebellar ataxias. In the majority of such cases for which the molecular defects have been identified, the ubiquitinated polyglutamine-containing proteins aggregates are found in the nuclei (rarely in cytoplasm) of the degenerating neurons (Paulson H., 1999).