Comprehensive Diagnostic Criteria for MELAS Syndrome; a Case Study Involving an Elderly Patient With MT-TWm.5541C>T Mutation

Background: Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a matrilineal hereditary multi-system disease due to mutations of mitochondrial DNA. Though the initial diagnostic criteria prevail till nowadays, which take a range of clinical phenotypes into consideration including clinical onset after the age of 40, a confirmative diagnostic standard for MELAS is still needed.Case presentation: A 71-year-old female patient presented with recurrent stroke to our hospital. Magnetic resonance imaging showed a cerebral gyrus-like area with hyperintensity in the parietal-occipital lobe on DWI and this area expanded with disease progression. The Lac/Lip peaks were significantly inverted in the MRS imaging. Nucleic acid sequencing showed a MT-TWm.5541C>T mutation, and the mutation rate of the blood sample was 12.86%. The patient had a 6-year history of type 2 diabetes. The patient experienced recurrent stroke and was given coenzyme Q10 capsules and idebenone tablets to improve metabolism, vitamin B to nourish nerves, edaravone to scavenge oxygen free radicals, and oxcarbazepine to manage seizures. At 1-month follow-up, her condition was stable.Conclusion: Patients with MELAS syndrome have complex clinical manifestations. Our data demonstrated that, for patients with atypical cerebral infarction and suspected MELAS syndrome, gene sequencing and muscle biopsy should be completed in time, which may serve as a reference for the diagnostic criteria of MELAS syndrome.