Clinical Findings of Type 3 Spinocerebellar Ataxia

Background: Spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of progressive autosomal disorders of dominant inheritance with a gradual degeneration of the cerebellum and related pathways [1]. This leads to a movement disorder, loss of balance and coordination, accompanied by slurred speech [2]. Among the approximately 40 types of SCA, the spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease, is the most clinically heterogeneous [3]. It involves the cerebellar, pyramidal, extrapyramidal, motor neuron and oculomotor systems [2]. Objectives: Understand the clinical findings of SCA3. Methods: The review was based on papers from SciELO and LILACS databases. Articles presented in full, written in English or Portuguese, were researched. Results: SCA3 is a consequence of the ATXN3 gene modification, which generates pathogenic repeated expansions of trinucleotides CAG, leading to polyglutamine coding. The common clinical phenotype includes the presentation of symptoms such as cerebellar ataxia, ophthalmoplegia, spasticity, basal ganglia symptoms, sensory symptoms, amyotrophy, including facial atrophy and fasciculations [4]. In addition, atrophy of the cerebellar vermis, hemispheres, brainstem and medial cerebellar peduncle are visualized on MRI in the early stages, resulting in an enlargement of the fourth ventricle. Furthermore, changes also occur in the caudate nucleus, putamen and upper cerebellar peduncle [5]. Conclusion: Through data analysis, there is a necessity to know the clinical and pathological characteristics of SCA3. This neurological disorder causes suffering for the patients, since it is a highly debilitating serious condition.