1/246. adult-onset MELAS presenting as herpes encephalitis. OBJECTIVE: To report an unusual presentation of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) manifested in late life with a clinical picture of herpes simplex encephalitis. DESIGN: Case report. SETTING: Clinical neurology department in a tertiary care hospital. CASE DESCRIPTION: A 55-year-old woman developed aphasia and delirium during ophthalmic herpes zoster infection treated with oral prednisone and ophthalmic steroids, which was followed by progressive cognitive decline without acute neurologic events for 5 years. At age 60, the patient presented with new onset of seizures, hemiparesis, and hemianopsia. Subsequently she developed cortical blindness, multiple traumatic soft tissue injuries from falls, acute psychosis, and severe dementia with periods of agitation. She died in a nursing home in March 1997, 6 years after initial presentation. RESULTS: magnetic resonance imaging scan of the brain showed hyperintensity on T2-weighted images involving temporal, parietal, and occipital lobes bilaterally as well as mild atrophy of brainstem and cerebellum. Single photon emission computed tomographic imaging showed hypoperfusion of temporal, parietal, and occipital lobes. Results of video electroencephalographic monitoring showed periodic lateralizing epileptiform discharges in temporal and occipital areas. The serum lactate level was normal in May 1996 and elevated in October 1996. The creatine kinase level was elevated with a 100% MM fraction in August 1991 and normal in March 1996. Results of repeated cerebrospinal fluid analyses indicated elevated protein levels. Analysis of dna was diagnostic of MELAS by mitochondrial dna point mutation at position 3243. The results of autopsy showed moderate cerebral, cerebellar, and brainstem atrophy with signs of infarction in temporal and parietal lobes bilaterally. CONCLUSIONS: The clinical presentation as well as age at onset of MELAS are highly variable. Onset of mitochondrial disorders can be provoked by febrile illness when there is mismatch between energy requirements and availability. In the differential diagnosis of herpes encephalitides, melas syndrome should be considered. ( info) |
2/246. Serial electroencephalographic findings in patients with MELAS. To clarify the electroencephalographic characteristics of mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS), the medical records and electroencephalograms of six patients with MELAS and two of their relatives with MELA (mitochondrial myopathy, encephalopathy, and lactic acidosis, without strokelike episodes) were retrospectively reviewed. All have a point mutation in the mitochondrial dna at nucleotide position 3243. The electroencephalograms (n = 79) were divided into four groups according to the time relation to the strokelike episode: (1) before the first strokelike episode, (2) within 5 days after the strokelike episode (acute stage), (3) between 6 days and 1 month after the strokelike episode (subacute stage), and (4) more than 1 month after the strokelike episode (chronic stage). In the acute stage, 10 of the 11 electroencephalograms (9 strokelike episodes in four patients) revealed focal high-voltage delta waves with polyspikes (FHDPS), which were recognized as ictal electroencephalogram. Ictal events during FHDPS included focal clonic or myoclonic seizure and migrainous headache. In the subacute and chronic stages, focal spikes or sharp waves and 14- and 6-Hz positive bursts were frequently recorded. The authors' results suggest that FHDPSs present a reliable and accurate indicator of a strokelike episode in patients with MELAS. ( info) |
3/246. Effect of coenzyme Q10 in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS): evaluation by noninvasive tissue oximetry. We evaluated the effect of coenzyme Q10 supplementation to two patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) by using noninvasive tissue oximetry with near-infrared spectra of hemoglobin from the quadriceps muscle during bicycle ergometer exercise. patients showed distinct oxygen consumption patterns reflecting the defect in oxidative phosphorylation and the impairment in oxygen utilization during exercise. Based on the oxygen consumption pattern, we considered one patient as having severe mitochondrial disorder and another patient as having mild one. After coenzyme Q10 supplementation, the oxygen consumption pattern of the patient with the severe form shifted to the mild one, while that of the patient with mild form remained unchanged. The shift of the pattern to the mild form correlated well with reduction of the sum of the serum lactate and pyruvate content during exercise. Noninvasive tissue oximetry may be useful to evaluate the effect of coenzyme Q10 supplementation to patients with mitochondrial encephalomyopathy including MELAS. ( info) |
| We describe a clinically full-blown MELAS patient, who had an A3243G point mutation of mitochondrial dna (mtDNA) in muscle and blood cells, and his family members. From the proband two muscle biopsies from the vastus lateralis muscle were analysed; one had typical ragged red fibers and focal cytochrome c oxidase deficiency and the other was completely normal. He also had a peripheral neuropathy confirmed by nerve conduction velocity and sural nerve biopsy studies. Axonal degeneration, relative loss of large myelinated fibers and paracrystalline inclusion bodies in the schwann cells were noted. Intriguingly, the A3243G mutation of mtDNA was not found in the sural nerve biopsy. Therefore, we conclude that tissue mosaicism is present in the muscle fibers and that the mtDNA mutation may not be detected in the nerve involved as proved by pathology. We also suggest that the involvement of specific tissues in patients with mitochondrial diseases should be further determined by single fiber mtDNA analysis. ( info) |
| OBJECTIVE: To describe methods of assessing cochlear implant candidacy in patients with potentially significant peripheral and central nervous system (CNS) degeneration. STUDY DESIGN: A patient with a degenerative CNS disease (melas syndrome) undergoing evaluation for cochlear implantation is described. SETTING: This study took place at a tertiary care center. PATIENT: A patient with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) who had cortical blindness and profound sensorineural hearing loss was evaluated and rehabilitated with cochlear implantation. INTERVENTIONS: Pure-tone audiogram, behavioral responses to promontory stimulation electrical auditory brainstem response, and electrically evoked middle-latency responses (MLRs) were used to assess eighth nerve, auditory brainstem, and cortical auditory pathways. cochlear implantation with Cochlear Corporation mini 22 implant was performed. RESULTS: Repeatable electrically evoked MLRs and behavioral responses to promontory stimulation documented the presence of auditory cortical responses. Successful implantation resulted in open set speech recognition and communication using the auditory/oral mode. CONCLUSION: This report describes successful implantation in a patient with melas syndrome and demonstrates the ability to preoperatively confirm the integrity of brainstem and cortical auditory pathways despite significant CNS degeneration. ( info) |
6/246. MELAS with prominent white matter gliosis and atrophy of the cerebellar granular layer: a clinical, genetic, and pathological study. This report concerns an autopsy case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) with unusual neuropathological findings. The patient was a Japanese woman who was 21 years old at the time of death. Her mother is a patient with genetically confirmed MELAS. Her clinical manifestations included convulsions and lactic acidosis in the latter half of the first decade of life, followed by deafness, dementia, muscle weakness in the lower extremities, slight ataxia in the upper and lower extremities, and diabetes mellitus. Muscle biopsy revealed ragged-red fibers, and genetic study showed a point mutation at nucleotide pair 3243 in mitochondrial dna. She died of lactic acidosis. In the clinical course, she did not develop stroke-like episodes. The neuropathological examination revealed not only minute to small necrotic foci in the cerebral cortex, amygdala, hippocampus, and cerebellum, but also prominent white matter gliosis in the central nervous system and cerebellar cortical degeneration of granular cell type. Our neuropathological findings, including prominent white matter gliosis of the central nervous system and cerebellar cortical degeneration of granular cell type, may indicate morphologically widespread cellular dysfunction, not restricted to either neuronal or vascular derangement, in the brain pathology of MELAS. ( info) |
7/246. dystonia as a presenting feature of the 3243 mitochondrial dna mutation. A variety of neurologic phenotypes have been described in patients with mitochondrial disorders. We report a 32-year-old man in whom dystonia was the salient and presenting feature of a mitochondrial dna mutation. He presented at age 23 with writer's cramp and progressed over 5 years to exhibit dystonia in facial muscles and lower limbs. He also has exercise intolerance, mild, bilateral ptosis, proximal muscle weakness, and sensorineural hearing loss. Molecular genetic analysis of blood, urine, and muscle biopsy demonstrated the presence of a heteroplasmic point mutation at nucleotide position 3243. The 3243 mtDNA mutation has pleomorphic manifestations, and dystonia should be added to the list of associated clinical features. ( info) |
8/246. The mitochondrial dna A3243G mutation in portugal: clinical and molecular studies in 5 families. Out of 90 Portuguese patients with mitochondrial cytopathy, six harbored the A3243G mutation in the mtDNA tRNA(Leu(UUR)) gene ('MELAS mutation'). They had heterogeneous clinical features, including myopathy with stroke-like episodes, progressive external ophthalmoparesis, diabetes mellitus, and subacute encephalopathy. Histochemical and biochemical analyses of muscle biopsies showed abundant ragged-red fibers reacting positively with the cytochrome oxidase stain, and decreased respiratory chain enzyme activities. On average, the proportion of mutated mtDNA was 67% (20-88%) in tissues from patients and 21% (0-49%) in blood from 20 maternal relatives. The proportion of mutated mitochondrial genomes in muscle did not correlate with clinical presentation or duration of disease. This study, the first in Portuguese patients, confirms the frequent occurrence of the A3243G mutation in patients with mitochondrial diseases, and emphasises the usefulness of genetic testing in reaching a correct diagnosis. ( info) |
9/246. Flow cytometric evaluation of defects of the mitochondrial respiratory chain. Cultured human skin fibroblasts from 12 patients with a variety of mitochondrial respiratory chain defects were examined for their capacity to oxidize dihydrorhodamine-123 to the fluorescent molecule rhodamine-123 using a flow cytometer. We found that cells from patients with functional defects in respiratory chain enzymes were less able to oxidize dihydrorhodamine-123 than those of healthy controls. Ten of the cell strains had reduced activity in at least one of the respiratory chain complexes and also showed significantly reduced fluorescence when compared to the mean of eight normal control cell strains. One patient had mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (with the A3243G mutation) and reduced respiratory chain activities in muscle and liver. Molecular analysis did not show the mutation in cultured skin fibroblasts, and had correspondingly normal fluorescence. The 12th cell strain showed reduced fluorescence but did not reach statistical significance. This strategy could be of use in helping direct further investigations in patients, and in studying the biochemical pathogenesis of mitochondrial dna mutations in cybrid studies. ( info) |
10/246. skin manifestations of a patient with mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes (melas syndrome). skin abnormalities in a patient with newly diagnosed melas syndrome are reported. He presented with scaly, pruritic, diffuse erythema with reticular pigmentation on his entire body. Moderate hypertrichosis was also noted on the lower extremities. Thickened arrector muscles with longitudinal and cross sections were seen in the dermis. Analysis of mitochondrial dna in a biopsy specimen from the biceps brachii disclosed the presence of an A-to-G point mutation at nucleotide pair 3243. Electron microscopy revealed marked increase in the number of morphologically abnormal mitochondria in the arrector muscles of the involved skin. This is the first report of a melas syndrome patient with skin manifestations and evidence of morphologically abnormal mitochondria. ( info) |