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PubMedDate not supplied

Melas syndrome.

An 11 year old male presented with headache, vomiting and weakness of right side of body. One day after admission he developed right focal seizures. He had 5 previous episodes of stroke, the first at 11 months age. His milestones were normal upto the first episode but subsequent mile stones were delayed. His serum and CSF lactic acids were raised. Muscle biopsy showed ragged red fibres on modified Gomori-trichrome staining. His EEG, CT scan and MRI were normal this time. The child improved spontaneously after 7 days. His recovery time progressively became shorter with each episode of stroke. Maximum time for recovery was noted during first episode and least in current episode. This is the first report of Melas syndrome in Indian literature.

Child↗
PubMed1998

Childhood MELAS syndrome presenting with seizure and cortical blindness: a case report.

An 11-year-old boy presented with seizure and cortical blindness. A T1 weighted magnetic resonance image of the brain showed high signal intensity in the bilateral corpus striatum and long T1 and T2 changes in the bilateral occipital and cerebellar hemispheric regions. Increased cerebrospinal fluid lactate concentration of 56.7 mg/dl and blood lactate concentration of 34.2 mg/dl were also noted. A muscle biopsy obtained from the quadriceps femoris muscle showed the presence of ragged red fibers and mitochondrial DNA (mtDNA) analysis showed an A-->G mutation at nucleotide position 3243. MtDNA analysis of the patient's mother revealed the same mutation. These findings indicated MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes).

Blindness, Cortical↗
PubMedDate not supplied

Moyamoya disease initially mimicking MELAS syndrome in a 14-month-old child.

Moyamoya disease is a neurological disease rarely seen in children outside Japan. It is difficult to differentiate moyamoya disease in its early stage from mitochondrial disorders in children when nontraumatic ischemic stroke is considered. We present a 14-month-old Taiwanese female child who had suffered from sudden onset of nontraumatic seizure attack, after which progressive left limb weakness was noted. Initial brain imaging and a series of laboratory studies were performed which suggested mitochondrial disorders, especially mitochondrial encephalopathy, lactic acidosis, and strokelike episodes (MELAS) syndrome. The patient underwent an oral glucose lactate stimulation test (OGLST), and mitochondrial disorders were not favored. MR angiography of the circle of Willis showed moyamoya disease. The patient then underwent an encephalo-duro-arterio-myo-synangiosis (EDAMS) operation. Evaluation of the neurodevelopmental and intelligence outcome required close long-term follow-up.

Brain↗
PubMed1991

MELAS syndrome. Report of two patients, and comparison with data of 24 patients derived from the literature.

We present two unrelated MELAS patients, and compare them with 24 patients derived from the literature. In most patients the stroke-like features of the MELAS syndrome occur late in the course of the disease. The diagnosis is based on characteristic clinical symptoms, presence of lactic acidemia, mitochondriopathy in muscle, and low density lesions on cerebral CT, most frequently occurring in the posterior and parieto-temporal regions. In some cases, a metabolic defect could not be demonstrated, in other cases a partial deficiency of various respiratory chain enzymes was found.

Biopsy↗
PubMed2000

[Mitochondrial diabetes complicated by or associated with "MELAS" syndrome?].

We report the case of fifty-two year-old mentally deficient female who presented with diabetes mellitus, deafness, stroke-like episodes, cardiomyopathy, and macular pattern dystrophy of the retina. Her brain exhibited calcification within basal ganglia, lactacidaemia was not increased. Although her skeletal muscles had never been clinically impaired, a quadriceps biopsy led to the diagnosis of mitochondrial disease because it exhibited ragged red fibers and heteroplasmic point-mutation at position 3243 of the mitochondrial DNA, although not any detectable respiratory chain complex deficiency was found. The mutant percentage in muscle was 70 p.100 and 5 to 10 p.100 in leukocytes. The question of whether a diabetic microangiopathy may be responsible stroke-like episodes is discussed. We suggest it was rather a complicated form of diabetes-deafness than a incomplete MELAS syndrome associated with mitochondrial diabetes.

Brain↗
PubMed1988

MELAS syndrome: characteristic migrainous and epileptic features and maternal transmission.

Severe prolonged migrainous symptoms and prolonged partial status epilepticus are characteristic features of the MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). Maternal transmission previously found in myoclonus epilepsy and ragged-red fibers (MERRF), another mitochondrial disease, is suggested in this disorder as well.

Adolescent↗
PubMed1999

Tissue mosaicism in the skeletal muscle and sural nerve biopsies in the MELAS syndrome.

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.

Adult↗
PubMed1991

[Complex I (NADH coenzyme-Q-reductase) deficiency, MELAS syndrome and hypertrophic cardiomyopathy].

A 24-year-old male had a deficiency of the complex I (NADH coenzyme-Q-reductase) of the mitochondrial respiratory chain, which clinically presented as a mitochondrial encephalomyopathy, with lactic acidosis and stroke-like episodes (MELAS syndrome). The encephalopathic episodes were preceded by migraine and were characterized by focal deficit signs, motor partial seizures and hypodense areas in the CT scan. An echocardiographic diagnosis of hypertrophic cardiomyopathy without intracavitary thrombi was made. It is suggested that hypertrophic cardiomyopathy is caused by the mitochondrial abnormalities that have been reported in the myocardium, and that migraine and cerebral infarctions are associated with abnormalities in the mitochondria from the endothelium and smooth muscle fibres of the cerebral small arteries and arterioles.

Acidosis, Lactic↗
PubMed1993

Generalized mitochondrial microangiopathy and vascular cytochrome c oxidase deficiency. Occurrence in a case of MELAS syndrome with mitochondrial cardiomyopathy-myopathy and combined complex I/IV deficiency.

The pathophysiological significance of the mitochondrial microangiopathy in MELAS (mitochondrial encephalopathy, lactic acidosis, and strokelike episodes) syndrome was evaluated in an autopsy study of a nearly 13-year-old girl who had suffered from multiple infarctlike lesions in the brain, a mitochondrial myopathy-cardiomyopathy, and a generalized mitochondrial microangiopathy. Cytochemically, defects of cytochrome c oxidase (complex IV) were visualized by light and electron microscopy in the skeletal and heart muscle and in the altered vessels, as well as in single bile duct cells, with the activity of the hepatocytes being diffusely reduced, whereas in the brain, the cytochemical activity was only slightly diminished. Biochemical studies revealed a 50% reduction of both NADH (the reduced from of nicotinamide-adenine dinucleotide) dehydrogenase (complex I) and complex IV in the skeletal muscle. In the brain, complex I was diminished to 20%, whereas complex IV was only slightly below the low-normal range. Immunohistochemical studies with the use of subunit-specific antiserum samples against cytochrome c oxidase showed a varying protein profile, with loss of both mitochondrially and nuclearly derived subunits being most pronounced in the heart muscle and lesser in the skeletal muscle. In the brain, liver, bile ducts, and especially the vessels, no loss of enzyme protein content was observed. The results illustrate heterogeneous tissue expression of respiratory chain defects in MELAS syndrome and indicate that vascular cytochrome c oxidase deficiency may be involved in the cerebral manifestation of the disease, whereas in other organs like the heart, a similar pathogenetic importance of the microangiopathy cannot be verified.

Adolescent↗
PubMed2002

The course of vision disturbances in a patient with the MELAS syndrome.

BACKGROUND: This article describes the neuropsychological and ophthalmic symptoms presented by a patient with MELAS, a mitochondrial cytopathy. This rare disease is characterized by a remitting-relapsing course against the background of a slowly progressive degenerative process. CASE REPORT: The patient is a 22-year-old Polish female, with initial onset of symptoms in 1994; the clinical diagnosis of MELAS was established in 1998, and confirmed in 2000 by the discovery of a novel mtDNA mutation. Her visual acuity fluctuates from near-normal to near-blindness, often changing dramatically within a matter of weeks; the visual field has more or less steadily narrowed to lunate. Visual evoked potentials show sporadic disturbances, while the nerve fiber layer shows significant attenuation. The evidence points to a complex etiology, involving both cortical damage and attenuation of the optic nerves and neural pathways. A similar two-phase pattern--episodic disturbances with rapid spontaneous recovery against a background of progressive deterioration--occurs in neuropsychological testing, which reveals progressive dementia and episodic aphasia. CONCLUSIONS: The peculiar pathomechanism of MELAS results in simultaneous insults to various parts of the central and peripheral nervous systems, creating the complex and highly variable pattern seen in this patient. In clinical practice care should be taken not to overlook the possible significance of such a pattern appearing in various systems and on varying levels.

Adult↗
PubMed1995

MELAS syndrome: imaging and proton MR spectroscopic findings.

PURPOSE: To evaluate imaging findings in MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, strokes) syndrome for the presence and location of infarctions and the presence of lactate. METHODS: Eight patients were studied with MR (n = 8) and CT (n = 2). One patient underwent single-photon emission CT with technetium 99m hexamethyl-propyleneamine oxime and one patient had conventional catheter angiography. One fixed brain was studied with MR imaging. Five patients underwent single volume proton MR spectroscopy. Imaging studies were evaluated for atrophy, edema, and infarctions. Proton MR spectroscopy was visually analyzed for presence or absence of lactate. RESULTS: One patient showed a cerebral infarction, and later a second distant infarction developed. One patient showed a transient area of cortical edema. Two patients had small nonspecific periventricular white matter abnormalities and one patient had diffuse white matter hyperintensities. Two patients had nonspecific MR abnormalities (probably age-related changes), and two had normal MR findings. None had basal ganglia involvement. Proton MR spectroscopy showed presence of lactate in one case with transient cortical edema; in two cases with nonspecific (probably age-related) brain findings; and in two patients with normal MR findings. CONCLUSIONS: Patients with MELAS have a variety of MR findings. The fact that proton MR spectroscopy showed lactate in all five cases studied, regardless of MR findings, indicates that proton MR spectroscopy may be more sensitive in the detection of MELAS-associated abnormalities than MR imaging.

Adolescent↗
PubMed2002

Neuronal hyperexcitability in stroke-like episodes of MELAS syndrome.

BACKGROUND: The pathogenesis of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) remains unknown. METHODS: Fourteen stroke-like episodes in six patients with MELAS were studied using clinical, neuroradiologic, and electrophysiologic approaches. In two patients postmortem examination was done. RESULTS: Headache and epileptic seizure were the most common presenting symptoms. In 13 of 14 episodes the cerebral cortex was primarily involved with variable subcortical edema particularly in the temporal, occipital, and parietal cortex. Repeated MRI performed in two episodes revealed progressive spread of the cortical lesion to the surrounding cortex for a few weeks after the onset of symptoms. In 6 of 11 episodes T1-weighted hyperintense cortical signal compatible with cortical laminar necrosis was seen during subacute stage of the episode. Fat-suppression MRI confirmed intracortical gyral hemorrhage in one episode. Petechial gyral microhemorrhages were also pathologically confirmed in the autopsy of another patient. In 9 of 11 episodes focal epileptiform discharges on EEG were noted in the acute brain lesion. In seven of nine episodes focal cortical hyperperfusion was seen in SPECT studies. CONCLUSION: The stroke-like episodes in MELAS may reflect neuronal hyperexcitability, which increases energy demand and creates energy imbalance between energy requirement and adequate availability of adenosine triphosphate due to oxidative phosphorylation defect particularly in the susceptible neuronal population, causing cortical necrosis. The episodic nature of stroke-like episodes is unexplained.

Adult↗
PubMed1995

Cerebral metabolism of oxygen and glucose in a patient with MELAS syndrome.

We studied cerebral oxygen and glucose metabolism as well as cerebral blood flow using positron emission tomography (PET) in a case with MELAS showing dementia, diabetes mellitus, ataxia and lactic acidosis without any signs of stroke. This case, confirmed to have a point mutation at position 3243 in the transfer RNA gene of mitochondrial DNA, developed a stroke-like episode 8 months after the PET study. Uncoupling was observed between cerebral oxygen metabolism and cerebral blood flow with reduced fractional oxygen extraction ratio, indicating "hyperemia", not ischemia. The "hyperemia" may be closely related to the malfunction of mitochondria in aerobic energy production. A drastic decrease in cerebral oxygen metabolism (CMRO2) was found globally in contrast to preserved cerebral glucose metabolism (CMRglu), resulting in a remarkable decrease in the metabolic ratio (CMRO2/CMRglu). The dissociation between cerebral glucose and oxygen metabolism may be characteristic of MELAS.

Adult↗