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[A case of MELAS associated with prosopagnosia, topographical disorientation and PLED]
1Department of Internal Medicine, Kawasaki Medical School.
Abstract:
We report a case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) associated with prosopagnosia, topographical disorientation, and periodic lateralized epileptiform discharge (PLED) on electroencephalography (EEG) in a 23-year-old right-handed man. The first MELAS attack occurred on March 1, 1991, while the patient was drinking. Magnetic resonance imaging (MRI) revealed a lesion of abnormal intensity in the left occipital lobe. The second attack occurred on October 1, 1991. This time, the major symptoms were visual loss of acute onset, nausea, and vomiting. EEG examination showed transient PLED. MRI revealed a new area of abnormal intensity in the right occipital lobe, lingual gyrus, fusiform gyrus and the posterior part of the parahippocampal gyrus. During the clinical course of the patient, prosopagnosia and topographical disorientation appeared. There have been few reports of MELAS associated with prosopagnosia, topographical disorientation, and PLED. However, MELAS attacks tend to occur in the cortex of the occipital lobe. We therefore believe that these neuropsychological symptoms and PLED are likely to be associated with MELAS.
Insights
This study details a rare case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) presenting with prosopagnosia and topographical disorientation. These symptoms, along with periodic lateralized epileptiform discharges (PLEDs), were linked to occipital lobe involvement in MELAS.
Area of Science:
- Neuroscience
- Neurology
- Genetics
Background:
- Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a rare mitochondrial DNA disorder.
- Neurological manifestations of MELAS can vary widely, but occipital lobe involvement is frequently observed.
Observation:
- A 23-year-old male presented with recurrent stroke-like episodes characteristic of MELAS.
- The patient developed prosopagnosia (face blindness) and topographical disorientation (difficulty navigating).
- Electroencephalography (EEG) revealed periodic lateralized epileptiform discharges (PLEDs), and MRI showed occipital lobe lesions.
Findings:
- This case highlights a unique association between MELAS, prosopagnosia, topographical disorientation, and PLEDs.
- Neuropsychological deficits and PLEDs correlated with occipital lobe lesions in the affected individual.
- The findings suggest a potential link between MELAS, occipital cortical dysfunction, and specific cognitive impairments.
Implications:
- This case expands the spectrum of known neurological and neuropsychological manifestations of MELAS.
- It underscores the importance of considering MELAS in patients presenting with stroke-like episodes and cognitive deficits, particularly those involving visual processing and spatial orientation.
- Further research may elucidate the precise mechanisms underlying these complex associations in MELAS.