Oculomasticatory rhythmic movements, insomnia and stroke-like episodes in a patient with POLG mutation

Area of Science:

• Genetics
• Neurology
• Mitochondrial Biology

Background:

• The POLG gene provides instructions for making an enzyme called mitochondrial DNA polymerase, essential for replicating and repairing mitochondrial DNA.
• Mutations in POLG are a significant cause of inherited mitochondrial diseases, often presenting with diverse neurological symptoms and variable age of onset.
• Mitochondrial diseases can affect multiple organ systems, with the nervous system frequently involved due to high energy demands.

Observation:

• An elderly male patient presented with an unusual constellation of symptoms including a stroke-like episode, chronic insomnia, and oculomasticatory rhythmic movements.
• Medical history revealed long-standing constipation and progressive bilateral ophthalmoplegia (paralysis of eye muscles) starting in his early sixties.
• Neurological examination confirmed bilateral complete ophthalmoplegia, ptosis (drooping eyelids), and involuntary rhythmic movements of the eyes and jaw.

Findings:

• Brain imaging revealed abnormalities consistent with a stroke-like episode.
• Genetic analysis identified a homozygous missense mutation in the POLG gene.
• The patient's clinical presentation, including chronic constipation, encephalopathy, chronic insomnia, and oculomasticatory myorrhythmia, represents an atypical phenotype for POLG mutations.

Implications:

• This case expands the known clinical spectrum of POLG gene mutations, particularly in individuals over 60 years of age.
• The rare combination of stroke-like episodes, chronic insomnia, and oculomasticatory rhythmic movements associated with a POLG mutation highlights the complexity of mitochondrial disorders.
• Recognizing such atypical presentations is crucial for accurate diagnosis and management of mitochondrial diseases in the elderly population.