Ptosis as the Only Presenting Feature of a Mitochondrial Cytopathy

Abstract

Mitochondrial cytopathies (MCs) result from a genetic defect in cells that leads to reduction in energy production. This can affect any organ, especially those with high-energy consumption. The authors highlight two cases of MCs who presented with isolated ptosis. The characteristics initially suggested myasthenia gravis. Subsequently the ptosis became progressive and the diagnosis was revised to MC because mitochondrial rearrangements were found in skeletal muscle DNA. Limb muscle biopsy was conclusive in one patient, but the other patient required periocular muscle to confirm the diagnosis. MC can present in this manner because heteroplasmy of mitochondrial DNA means that not all organs will exhibit clinical manifestations.

Keywords::

• age-related CPEO
• chronic progressive external ophthalmoplegia
• isolated ptosis
• mitochondrial cytopathies
• myasthenia gravis

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.