Clinical,neuroimaging and myopathological features of MELAS:a retrospective analysis of 31 patients / 中华神经科杂志

ABSTRACT

Objective To investigate the clinical,neuroimaging and myopathological features of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes(MELAS).Methods The clinical manifestations,neuroimaging and myopathological features of 31 patients with MELAS diagnosed in our Neuromuscular Center in the recent 7 years were retrospectively analyzed.A3243G point mutations were analyzed by RFLP method in 10 patients.Results ①Clinical featuresThere were 18 male patients and 13 female patients.The age of onset ranged from 3 to 43 years,averaging 21.9 years.The averaged duration was 4.9 years.Thirteen patients in this group had family history of maternal inheritance pattern.The main clinical manifestations included short stature(26 patients),recurrent headache and vomiting(24 patients), muscle weakness(22 patients),epileptic seizure(21 patients),cognitive decline(19 patients),visual disturbance(17 patients),sensorineural deafness(16 patients),ataxia(6 patients),psychiatric symptom (8 patients),external ophathalmoplegia(2 patients)and diabetes mellitus(9 patients).The serum CK level was slightly elevated in 6 patients,and the fasting blood lactic acid was increased in 15 of the 18 detected patients.②Neuroimaging featuresThe stroke-like lesions were mostly confined to cerebral cortex, including temporal lobe(24 patients),occipital lobe(21 patients),parietal lobe(12 patients)and frontal lobe(4 patients).Three patients had deep white matter involvement.Migrating stroke-like lesions were confirmed in 4 patients by repeated cranial CT/MRI examination.In addition,cerebral atrophy(17 patients)and bilateral basilar ganglion calcification(11 patients)were found.③Myopathological features Scattered ragged red fibers(RRF)in various number were found in all the patients by MGT staining.Other founding included strongly SDH-reactive blood vessel(27 patients),COX enzyme deficiency(19 patients), and mild to moderate lipid storage in RRF(20 patients).④MtDNA analysis showed 9 patients with A3243G point mutation in all the detected 13 patients.Conclusion The clinical and neuroimaging features may offer important clue to the diagnosis of MELAS,but a definite diagnosis of MELAS relies on the myopathology and mtDNA mutation analysis.