MRI Signal Abnormalities of the Inferior Olivary Nuclei in Spinocerebellar Ataxia Type 2

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant spinocerebellar degeneration, associated with extended repeats of the trinucleotide CAG in the ATXN2 gene on the long arm of chromosome 12. Magnetic resonance imaging (MRI) of SCA2 showed significant atrophies of the brainstem, middle cerebellar peduncles, and cerebellum. We report two genetically proven SCA2 patients who showed hypertrophy of the inferior olivary nuclei on proton density- and T2-weighted MRI. This pattern has never been reported in patients with SCA1, SCA3, or SCA6, and may make it possible to differentiate SCA2 from other hereditary spinocerebellar ataxias.