Atypical presentations of leigh syndrome: a case series and review.

Patients with Leigh syndrome classically present in early childhood with developmental regression, ataxia, and hypotonia with subsequent respiratory and brainstem dysfunction. However, the clinical presentation can be highly variable. This report presents five cases of Leigh syndrome with atypical presentations. The first patient is a 17-month-old female who presented with progressive limb weakness diagnosed as Guillain-Barre syndrome. Postmortem examination demonstrated Leigh syndrome confined to the spinal cord. The case series then describes two sisters one of whom presented at 11 years of age with central respiratory failure and encephalopathy. Her 15-year-old sister presented with a progressive diplegia. The fourth patient presented with bronchiolitis and apnea at 3 months of age due to bilateral brainstem lesions. Her second cousin presented at 6 months of age with hypotonia, blindness, and tonic seizures. All patients had laboratory and radiologic findings consistent with Leigh syndrome. Evidence of spinal cord involvement was observed on magnetic resonance imaging in four of the five patients. Leigh syndrome can involve any level of the neuroaxis, resulting in a wide variety of presentations. Many atypical variants are observed, of which clinicians should be aware. Evidence of brainstem or spinal cord involvement should also be sought in patients with Leigh syndrome.