Involvement of Cerebellum in Leigh Syndrome: Case Report and Review of the Literature.

Background: Leigh syndrome is an early-onset progressive neurodegenerative disorder typically involving lesions of the bilateral basal ganglia, thalami, and brainstem. Isolated involvement of the cerebellum is uncommon.

Methods: We present a six-year-old boy with Leigh syndrome who presented with recurrent episodes of ataxia and dysarthria. He was diagnosed with Leigh syndrome at two years of age with bilateral basal ganglia lesions on brain magnetic resonance imaging (MRI). Genetic testing confirmed a diagnosis of Leigh syndrome secondary to a homoplasmic mitochondrial DNA mutation (m.9176T>C). He experienced regressive episodes (ages five and six years). Each regressive episode had a similar presentation with worsening of baseline ataxia and dysarthria. The first episode mimicked infectious cerebellitis, with elevated cerebral spinal fluid (CSF) protein and white blood cell count. No organisms were isolated from the CSF/blood during any of the regressive episodes. Brain MRI consistently showed cerebellar lesions, however cerebellar spectroscopy during the second episode found an elevated lactate peak, a decrease of the N-acetylaspartate peak, and elevation of the choline peak; consistent with an acute exacerbation of Leigh syndrome.

Conclusions: Leigh syndrome can present primarily with involvement of the cerebellum, and it should be considered in the differential diagnosis for acute cerebellitis.