OVERLAPPING SYNDROME OF MERRF AND MELAS - MOLECULAR AND NEURORADIOLOGICAL STUDIES

We describe a 42-year-old woman with overlapping syndrome of MELAS (mi tochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and MERRF (myoclonus epilepsy and ragged-red fibers). Clinic ally, she had episodic headache, stroke-like episode with left hemipar esis and lactic acidosis commonly found in MELAS syndrome. However, my oclonus seizure, and ataxia with dyssynergic gait characteristic of ME RRF were also noted. Computed tomographic scans showed a right temporo -parietal hypodense lesion. The lesion disappeared 20 months later, ev en magnetic resonance images also failed to reveal this abnormality. A molecular analysis of mitochondrial DNA was conducted by using restri ction endonucleases ApaI and NaeI. A transition from A to G was found at the nucleotide position 3243, but not found at the 8344th nucleotid e pair. In this report, we document the fluctuating CT changes and emp hasize the importance of molecular analysis in patients with overlappi ng syndrome of mitochondrial encephalomyopathies.