Adult-onset Leigh Syndrome with a m.9176T>C Mutation Manifested As Reversible Cerebral Vasoconstriction Syndrome

Area of Science:

• Neurology
• Genetics
• Vascular Neurology

Background:

• Adult-onset Leigh syndrome is a rare mitochondrial disorder typically presenting with neurological deficits.
• Reversible Cerebral Vasoconstriction Syndrome (RCVS) is characterized by multifocal cerebral artery narrowing and typically presents with thunderclap headaches.

Observation:

• A 26-year-old woman presented with sudden headache, ptosis, and diplopia.
• Neuroimaging revealed a brainstem lesion and multifocal cerebral artery narrowing, initially suggesting RCVS.
• Elevated serum pyruvate and subsequent genetic analysis identified the m.9176T>C mutation in mitochondrial DNA.

Findings:

• The patient's symptoms improved with vasodilatation, consistent with RCVS.
• The genetic findings confirmed a diagnosis of adult-onset Leigh syndrome.
• The study links Leigh syndrome to an RCVS-like presentation.

Implications:

• This case expands the phenotypic spectrum of adult-onset Leigh syndrome.
• It highlights the importance of considering mitochondrial disorders in patients presenting with RCVS.
• Potential mechanisms include baroreflex dysfunction or endothelial dysfunction secondary to the brainstem lesion.