Phenotype variability in spinocerebellar ataxia type 2: A longitudinal family survey and a case featuring an unusual benign course of disease

Abstract

We report a 67 years old female patient out of a multigenerational family with spinocerebellar ataxia type 2 (SCA2) with an unusually benign course of disease. Although all SCA2 gene carriers have by now developed the predominant gait ataxia and brainstem oculomotor dysfunction, the index patient presented with a very mild course of disease, scoring only six points on the Scale for the Assessment and Rating of Ataxia after a disease duration of 13 years. Otherwise, intragenerational variability within family members such as the age at onset of disease and the course of disease was low. Reinvestigation of the genetic background variables in the SCA2 gene carrier reported here showed 27 repeats in the normal allele and 37 noninterrupted repeats in the abnormal allele. Interestingly, this patient has been taking lithium-carbonate over more than 30 years because of psychotic depression. Although anecdotic, this SCA2 case may provide promising insights into possible disease modifying mechanisms in SCA2.