Article: Olivopontocerebellar atrophy

Olivopontocerebellar atrophy (OPCA) are a group of diseases characterized by neuronal degeneration in the cerebellum, pontine nuclei, and inferior olive. They are also referred to as spinocerebellar ataxias (SCA) or atrophies. Some also involve brain stem motor nuclei and/or cerebral cortex. All produce gait ataxia, and some also result in tremors, proprioceptive abnormalities, dysarthria, brain stem motor impairment, or dementia. Most are autosomal dominant in inheritance pattern. The primary cause of these hereditary ataxias also appears to be an unstable expansion of the polyglutamine trinucleotide repeat CAG, similar to Huntington's disease. Non-inherited, or sporadic OPCA, is now considered a form of multiple system atrophy (MSA).[1]

Subcategories

Olivopontocerebellar atrophy is group of disorders which overlap certain other groups, such as spinocerebellar ataxia (SCA). Some but not all types of SCA are in the Olivopontocerebellar atrophy group. Some but not all Olivopontocerebellar atrophy conditions, are types of SCA. This situation causes some controversy and confusion about what terms and system of categorization should be used. The subcategories of Olivopontocerebellar atrophy are:

OPCA1

• OPCA, Menzel type (OMIM 164400)
• Spinocerebellar ataxia type 1 (SCA1)

OPCA2

• OPCA, Holguin type (OMIM 183090)
• Spinocerebellar ataxia type 2 (SCA2)
• OPCA, Fickler-Winkler type (OMIM 258300)

OPCA3

• Spinocerebellar ataxia type 7 (SCA7) (OMIM 164500)
• OPCA with retinal degeneration

OPCA4

• OPCA, Schut-Haymaker type (OMIM 164600)

OPCA5

• OPCA with dementia and extrapyramidal signs (OMIM 164700))

See also

• Multiple system atrophy