-Spinocerebellar ataxias (SCAs) constitute a heterogeneous group of neurodegenerative diseases characterized by progressive cerebellar ataxia in association with some or all of the following conditions: ophthalmoplegia, pyramidal signs, movement disorders, pigmentary retinopathy, peripheral neuropathy, cognitive dysfunction and dementia. Objective: To carry out a clinical and genetic review of the main types of SCA. Method: The review was based on a search of the PUBMED and OMIM databases. Results: Thirty types of SCAs are currently known, and 16 genes associated with the disease have been identified. The most common types are SCA type 3, or Machado-Joseph disease, SCA type 10 and SCA types 7, 2, 1 and 6. SCAs are genotypically and phenotypically very heterogeneous. A clinical algorithm can be used to distinguish between the different types of SCAs. Conclusions: Detailed clinical neurological examination of SCA patients can be of great help when assessing them, and the information thus gained can be used in an algorithm to screen patients before molecular tests to investigate the correct etiology of the disease are requested.KEY WORDS: spinocerebellar ataxias, cerebellar atrophy, genotype, phenotype. Ataxias espinocerebelaresResumo -As ataxias espinocerebelares (AECs) compreendem um grupo heterogeneo de enfermidades neurodegenerativas, que se caracterizam pela presença de ataxia cerebelar progressiva, associada de forma variada com oftalmoplegia, sinais piramidais, distúrbios do movimento, retinopatia pigmentar, neuropatia periférica, disfunção cognitiva e demência. Objetivo: Realizar uma revisão clínico-genética dos principais tipos de AECs. Método: A revisão foi realizada através da pesquisa pelo sistema do PUBMED e do OMIM. Resultados: Na atualidade existem cerca de 30 tipos de AECs, com a descoberta de 16 genes. Os tipos mais comuns são a AEC tipo 3, ou doença de Machado-Joseph, a AEC tipo 10, e as AECs tipo 7, 2 1, e 6. As AECs apresentam grande heterogeneidade genotípica e fenotípica. Pode-se utilizar um algoritmo clínico para a pesquisa dos diferentes tipos de AECs. Conclusões: O exame clínico neurológico minucioso nos pacientes com AECs pode auxiliar sobremaneira na avaliação clínica destes pacientes, utilizando-se desta forma de um algoritmo, com os dados clínicos, que pode servir como um instrumento de triagem para a solicitação dos testes de genética molecular, para a correta investigação etiológica.

Knowledge of primary ataxias has been growing rapidly in recent years. Here we review different forms of primary ataxia, including inherited forms, which are subdivided into congenital, autosomal recessive cerebellar ataxias, autosomal dominant cerebellar ataxias, episodic ataxias, X-linked ataxias, and mitochondrial ataxias, as well as sporadic ataxias and idiopathic degenerative ataxias. Secondary or acquired ataxias are also reviewed and the most common causes are discussed.

Spinocerebellar ataxia type 3 or Machado-Joseph disease is the most common spinocerebellar ataxia worldwide, and the high frequency of nonmotor manifestations in Machado-Joseph disease demonstrates how variable is the clinical expression of this single genetic entity. Anatomical, physiological, clinical, and functional neuroimaging data reinforce the idea of a degenerative process involving extracerebellar regions of the nervous system in Machado-Joseph disease. Brain imaging and neuropathologic studies have revealed atrophy of the pons, basal ganglia, midbrain, medulla oblongata, multiple cranial nerve nuclei, and thalamus and of the frontal, parietal, temporal, occipital, and limbic lobes. This review provides relevant information about nonmotor manifestations and extracerebellar symptoms in Machado-Joseph disease. The main nonmotor manifestations of Machado-Joseph disease described in previous data and discussed in this article are: sleep disorders, cognitive and affective disturbances, psychiatric symptoms, olfactory dysfunction, peripheral neuropathy, pain, cramps, fatigue, nutritional problems, and dysautonomia. In addition, we conducted a brief discussion of noncerebellar motor manifestations, highlighting movement disorders. © 2013 Movement Disorder Society.

OBJECTIVE:Spinocerebellar ataxias are neurodegenerative disorders involving the cerebellum and its connections. There are more than 30 distinct subtypes, 16 of which are associated with an identified gene. The aim of the current study was to evaluate a large group of patients from 104 Brazilian families with spinocerebellar ataxias.METHODS:We studied 150 patients from 104 families with spinocerebellar ataxias who had received molecular genetic testing for spinocerebellar ataxia types 1, 2, 3, 6, 7, 8, 10, 12, 17, and dentatorubral-pallidoluysian atrophy. A statistical analysis of the results was performed using basic descriptive statistics and the correlation coefficient (r), Student's t-test, chi-square test, and Yates' correction. The statistical significance level was established for p-values <0.05.RESULTS:The results show that the most common subtype was spinocerebellar ataxia 3, which was followed by spinocerebellar ataxia 10. Moreover, the comparison between patients with spinocerebellar ataxia 3, spinocerebellar ataxia 10, and other types of spinocerebellar ataxia revealed distinct clinical features for each type. In patients with spinocerebellar ataxia 3, the phenotype was highly pleomorphic, although the most common signs of disease included cerebellar ataxia (CA), ophthalmoplegia, diplopia, eyelid retraction, facial fasciculation, pyramidal signs, and peripheral neuropathy. In patients with spinocerebellar ataxia 10, the phenotype was also rather distinct and consisted of pure cerebellar ataxia and abnormal saccadic eye movement as well as ocular dysmetria. Patients with spinocerebellar ataxias 2 and 7 presented highly suggestive features of cerebellar ataxia, including slow saccadic ocular movements and areflexia in spinocerebellar ataxia 2 and visual loss in spinocerebellar ataxia 7.CONCLUSIONS:Spinocerebellar ataxia 3 was the most common subtype examined, followed by spinocerebellar ataxia 10. Patients with spinocerebellar ataxia 2 and 7 demonstrated highly suggestive features, whereas the phenotype of spinocerebellar ataxia 3 patients was highly pleomorphic and spinocerebellar ataxia 10 patients exhibited pure cerebellar ataxia. Epilepsy was absent in all of the patients with spinocerebellar ataxia 10 in this series.