RESUMO
INTRODUCTION: Information on achieving presymptomatic diagnosis of spinocerebellar ataxia (SCA) is limited. The advent of molecular diagnosis makes it possible to identify the carriers of different diseases and has also introduced the prospect of detecting diseases even before their onset. This has drawn attention to the ethical implications that must be considered in these subjects with a view to preserving their physical and psychological well-being. DEVELOPMENT: SCA is composed of a group of neurodegenerative disorders with autosomal dominant inheritance. Only a few publications have described the genetic counselling processes and guidelines to be followed during the process of presymptomatic diagnosis (PSD). The size of the multidisciplinary teams, their areas of expertise, and the number of counselling sessions are different for each of the studies analysed here. However, the basis of presymptomatic diagnosis originates in common guidelines to which members of our team have contributed recently. CONCLUSION: Presymptomatic diagnosis should be performed according to guidelines that safeguard the subjects' welfare. The diagnostic process is only recommended for patients over 18 years old with symptoms suggesting SCA, and a minimum risk of 50%. Genetic counselling programmes must be available in all centres that offer presymptomatic diagnosis of SCA.
