Objective: To describe 2 unrelated patients with novel variations in the POLG1 gene and features undistinguishable from multiple sclerosis, ie, optic neuritis, brain white matter hyperintense areas, and unmatched cerebrospinal fluid oligoclonal bands.
Design: Case report.
Setting: University hospital. Patients Both patients subsequently developed bilateral ophthalmoplegia, ptosis, myopathy, cardiomyopathy, ataxia, dysphagia, and hearing and cognitive impairment.
Main outcome measures: Detailed clinical and laboratory examinations including brain magnetic resonance imaging, morphological analysis of a muscle biopsy, characterization of mitochondrial DNA integrity, sequencing of the POLG1 gene, and screening of control subjects for POLG1 sequence variants.
Results: Ragged red fibers and multiple deletions of mitochondrial DNA were detected in the skeletal muscle. Four compound heterozygous variations, including 3 previously unreported, were identified in POLG1.
Conclusion: Clinicians should be aware of the existence of POLG1-related multiple sclerosis-like illness, as it has important implications for management, treatment, and genetic counseling.