The mains objective of this study was to evaluate the presence and presentation of muscle cramps in the different forms of SCAs.

Spinocerebellar ataxias (SCAs) are a group of autosomal dominant degenerative disorders, characterized by progressive damage to the structures of the cerebellum and its connections. The most common ataxias in the Brazilian population are SCA2, SCA3 and SCA10. Despite the heterogeneous character, they present common characteristics, being muscle cramps a prevalent symptom in certain types of ataxias. Studies associate cramps with SCAs but there is no accurate information on this symptom in the different types of SCAs.

Seventy-nine patients with a diagnosis of SCA were selected. The patients had: (1) confirmatory clinical and genetic diagnosis, (2) clinical characteristics and first-degree relatives with genetic confirmation, or (3) clinical diagnosis, family with autosomal dominant inheritance, but genetic test not yet completed. The subjects of the study answered a questionnaire to assess the characteristics of cramps. In order to evaluate the severity of their ataxias, the Scale for the Assessment and Rating of Ataxia (SARA) was used.

The cramps occurred in 18 patients (100%) of the AEC2 group, 17 patients (70.8%) of the AEC3 group, 5 patients (26.3%) of the AEC10 group, 4 patients (57.1%) and 8 patients (72.7%) from the "Undefined" group (p = 000.1). When comparing the cramp profile in the most affected groups, AEC2 and AEC3, it was demonstrated that the age of onset of cramps was on average 8 years earlier in patients with AEC2 (p = 0.03).

The most relevant finding of the study was a significant difference in the incidence of cramp in the analyzed groups, which was elevated in AEC2 and AEC3, with a predominance in the first group.