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Results for “MELAS Syndrome”

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At least 19 recordsLinked to original sources

PubMed1990

Magnetic resonance imaging in MELAS syndrome.

MELAS syndrome is a distinct clinical entity belonging to a group of mitochondrial encephalomyopathies characterized by the tetrad of myopathy, encephalopathy, lactic acidosis, and stroke-like episodes. Computed tomography (CT) and magnetic resonance (MR) findings are reviewed in a patient with MELAS. Serial CT studies demonstrated multiple "migrating" infarcts in various stages of evolution involving primarily the posterior temporal and occipital regions. MR was more sensitive than CT in demonstrating the number and extent of cortical lesions in this disease entity.

Acidosis, Lactic↗

PubMed1991

Magnetic resonance imaging shows specific abnormalities in the MELAS syndrome.

The MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) can be difficult to identify. We report MRI abnormalities that we believe are specific to this disorder in three patients with complete or partial MELAS syndrome. The patients all showed an unusual pattern on T2-weighted MRI with multifocal areas of hyperintense signal confined to the cortex of the cerebrum, cerebellum, and adjacent white matter. Some images suggested selective cortical involvement of deeper layers only. Deep white matter was relatively spared, distinguishing this from usual cerebrovascular disease or the edema after status epilepticus. Specificity of these findings is further suggested by a good correlation of these findings with the previously described unique postmortem brain pathology of MELAS.

Acidosis, Lactic↗

PubMed1990

[Ocular changes in MELAS syndrome].

The present paper reports on the clinical findings of a 34-year-old male patient with MELAS syndrome. MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis and strokelike episodes) belongs to a group of syndromes called mitochondrial encephalomyopathies that are characterized by changes of the mitochondrial respiratory chain and the histological finding of "ragged red fibers" in muscle biopsy. In our case the diagnosis was confirmed by multiple neurologic tests including muscle biopsy and biochemical analysis of the respiratory chain. The ocular findings included reversible, homonymous hemianopic visual field loss documented six years earlier, atypical retinitis pigmentosa with marked attenuation of the scotopic ERG, myopia and nuclear cataract of the right eye. An extracapsular cataract extraction with implantation of a posterior chamber lens was performed on the rigt eye, the course was unremarkable and vision improved. In dealing with patients presenting with ocular or neurologic signs indicating mitochondrial encephalopathy, the ophthalmologist should consider MELAS syndrome or any other of the mitochondrial encephalomyopathy syndromes as a possible etiology and take the necessary steps for further medical and neurologic evaluation of the patient.

Acidosis, Lactic↗

PubMed1995

CPEO and carnitine deficiency overlapping in MELAS syndrome.

Mitochondrial myopathy, encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is one of the mitochondrial encephalomyopathies that has distinct clinical features including stroke-like episodes with migraine-like headache, nausea, vomiting, encephalopathy and lactic acidosis. We report a 27-year-old woman who presented with partial seizure, stroke-like episodes including hemiparesis, hemianopia and hemihypethesia, sensorineural hearing loss, migraine-like headache, and lactic acidosis. Brain computed tomographic scan showed encephalomalacia in the right parieto-occipital area and recent hypodensity in the left temporoparieto-occipital area with cortical atrophy. Muscle biopsy revealed ragged-red fibers and paracrystaline inclusions in the mitochondria. Genetic study revealed an A to G point mutation at nucleotide position (np) 3243 of mitochondrial DNA. External ophthalmoplegia and ptosis were also found during two exaggerated episodes in this patient. Therefore, the overlapping syndrome of chronic progressive external ophthalmoplegia in the MELAS syndrome is considered in this case. Furthermore, we also found carnitine deficiency in this patient and she was responsive well to steroid therapy. Muscle biopsy also revealed excessive lipid droplets deposits. Therefore, the carnitine deficiency may occur in MELAS syndrome with the A to G point mutation at np 3243. We recommend the steroid or carnitine supplement therapy be applied to the MELAS syndrome with carnitine deficiency.

Adult↗

PubMed1996

[Follow-up studies and disorders of endocrinologic function in MELAS syndrome].

The clinical course of MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) is described in five cases. The age of onset was 9.2 years on average. Cerebral symptoms occurred at an age of 24.6 years on average. The diagnosis was only made later. Three patients died during the follow-up period. The mean age at death was 33.3 years, the average duration of the disease, 19.6 years. All patients suffered from progressive hearing loss, multiple strokes, and complex-partial and generalized seizures. They all had short stature, normal early development and 'ragged red fibers' in the muscle biopsy. Imaging studies (CT and MRI) showed bilateral calcification of basal ganglia and multiple strokes. One patient, admitted with epileptic status as initial symptom, showed lymphocytic pleocytosis in the cerebrospinal fluid; thus, in her case the differential diagnosis included encephalitis. Four patients were studied by dynamic endocrinological testing. Endocrinological disturbances were detected in three patients. Two of them suffered from hypothalamic-pituitary failure and one patient exhibited hyperprolactinemia. Endocrinological disturbances were considered an expression of the underlying cytopathy. Cerebral symptoms occurred rather late in the course of the disease and indicated poor prognosis.

Adolescent↗

PubMed1995

MELAS syndrome associated with diabetes mellitus and hyperthyroidism: a case report from Taiwan.

MELAS syndrome is a form of mitochondrial myopathy with manifestations of seizure, stroke-like syndrome, lactic acidosis, ragged red muscle fibres and mitochondrial encephalopathy. The syndrome has been reported in association with a variety of endocrine and metabolic disorders including diabetes mellitus (DM), hypothalamo-pituitary hypofunction, hypothalamic growth hormone deficiency and delayed puberty. Mitochondrial DNA (mtDNA) point mutation may be the major pathological defect. However, association of MELAS syndrome with hyperthyroidism has not previously been reported. A case is reported from Taiwan of a 32-year-old woman suffering from MELAS syndrome with associated DM and hyperthyroidism. When the latter was diagnosed in April 1988, the patient underwent subtotal thyroidectomy. There was no family history of thyroid disease. Because of repeated seizures, she had computed tomography (CT) and magnetic resonance imaging (MRI) of the brain which showed focal, low-density lesions over the cerebral hemispheres. Both serum and cerebral spinal fluid lactic acid levels were elevated. Mild elevations of serum T4 and T3 and a high titre of TSH receptor antibody were still present. Hyperglycaemia was noted during hospitalization and DM confirmed by oral glucose tolerance test. Muscle biopsy showed ragged red fibres. DNA analysis showed an A-to-G transition at the 3243rd nucleotide position of the tRNA(Leu(UUR)) gene of the mtDNA from the patient. Quantitative polymerase chain reaction (PCR) and restriction analysis revealed that about 60% of the blood mtDNA was of mutant type. The patient received antithyroid drugs for hyperthyroidism, diet control for DM and anti-epileptic drugs for seizure.

Adult↗

PubMed1996

Acute renal failure and the MELAS syndrome, a mitochondrial encephalomyopathy.

Melas (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) is one of a group of heterogeneous yet clinically distinct syndromes ascribed to a defect in mitochondrial function. Here, the case of a patient diagnosed with the MELAS syndrome who subsequently developed acute renal failure is reported. Although no clear renal insult was evident at the time, the clinical picture was consistent with the diagnosis of acute tubular necrosis. The patient's renal function subsequently returned to baseline. This article reviews the literature concerning renal involvement in the mitochondrial encephalomyopathies, including MELAS, and proposes a mechanism by which patients suffering from mitochondrial disorders may be more susceptible to renal hypoxic injury and acute renal failure.

Acidosis, Lactic↗

PubMed1996

Mitochondrial myopathy-encephalopathy-lactic acidosis-and strokelike episodes (MELAS) syndrome: CT and MR findings in seven children.

OBJECTIVE: The purpose of this study was to describe the imaging characteristics of mitochondrial myopathy-encephalopathy-lactic acidosis-and strokelike episodes (MELAS) syndrome. MATERIALS AND METHODS: Twelve CT scans and 15 MR images were retrospectively reviewed in seven patients with proven MELAS syndrome. Follow-up studies were performed in all patients, and the total follow-up period ranged from 3 months to 3 years. Images were analyzed in terms of lesion distribution, enhancement pattern, presence of mass effect or atrophy, calcification, and changes on follow-up studies. RESULTS: CT and MR imaging showed multiple cortical and subcortical infarctlike lesions, which crossed vascular boundaries, and various degrees of generalized cerebral and cerebellar atrophy. Lesions were distributed in the posterior, parietal, and occipital areas in six patients, the putamen in five, the caudate nucleus in two, the thalamus in two, the frontal lobe in two, the globus pallidus in one, and the brainstem in one. Contrast enhancement was noted in two of seven cases on MR images and in three of five cases on CT scans. In the early stage, infarctlike lesions showed swelling and mass effect. Lesions resolved with or without local tissue loss in five patients, and new lesions appeared in another part of the brain in five patients. Generalized atrophy progressed in six cases and was most severe in the posterior part of the cerebral hemispheres. CONCLUSION: Our results indicate that imaging findings of multiple migrating infarctlike lesions that are not limited to a specific vascular territory, especially in the basal ganglia and posterior part of the cerebral hemisphere in children, are diagnostic of MELAS syndrome.

Brain↗

PubMed1993

Ophthalmologic manifestations in MELAS syndrome.

We describe a 15-year-old boy with full-blown mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and chronic progressive external ophthalmoplegia (CPEO). He presented with visual disturbance, hearing impairment, continuous partial epilepsy on the right aspect of the face, and right hemiparesis since the age of 13. Four months later, he experienced another strokelike episode with continuous partial epilepsy on the left hand. Serial computed tomographic scans revealed bilateral parieto-occipital hypodense lesions with gyral enhancement and an additional low-density lesion in the right frontal area 4 months later, respectively. Results of laboratory examinations disclosed lactic acidosis and mitochondrial myopathy with many ragged-red fibers. To identify the defective gene in mitochondrial DNA, a simple molecular test was performed by using restriction endonuclease Apa I. A transition from A to G was found at nucleotide position 3243 of the tRNA(Leu) gene. Interestingly, the patient also had marked external ophthalmoplegia and ptosis commonly found in patients with CPEO. Therefore, we suggest that ophthalmoplegia also occurs in the MELAS syndrome.

Adolescent↗

PubMed1994

[MELAS syndrome. Clinical aspects, MRI, biochemistry and molecular genetics].

MELAS is a mitochondrial cytopathy characterized by encephalopathy with stroke-like episodes and lactic acidosis. Most patients exhibit an A-G transition mutation at np 3243 of mitochondrial DNA (tRNA(Leu)(UUR)). We present a family of four in which the mutation was discovered in blood and in muscle mt DNA. Two patients had the classic MELAS syndrome with multiple stroke-like episodes. Some episodes were precipitated by metabolic stress. The remaining two patients had an oligosymptomatic disease with mild chronic encephalopathy, small stature and hearing loss. MRI was followed over a period of 4-8 years, during which the MELAS patients showed progression from nonspecific multifocal signal change to typical extensive cortico-subcortical parieto-occipital lesions and progressive cerebral atrophy. MRI in the oligosymptomatic cases was normal, or showed non-progressive cerebellar atrophy. Biochemical findings were non-specific, indicating increased mitochondrial volume in all cases, and a relatively complex IV defect in one case. All patients were treated with coenzyme Q with varying clinical response. The percentage of mutant mt DNA in blood and muscle did not correlate with clinical severity. Pathogenetic theories based on molecular genetics, and the therapeutic regimen in terms of the underlying biochemical concepts are discussed.

Adolescent↗

PubMed1997

Sensorineural hearing loss in MELAS syndrome.

A case of sensorineural hearing loss (SNHL) in MELAS syndrome, a variety of mitochondrial cytopathy, is presented. Mitochondrial cytopathies have gone almost unreported in the otolaryngology literature, despite evidence from a recent review that about 60 per cent of such patients suffer from SNHL (Gold and Rapin, 1994). The same review revealed that only one of 117 case reports in the period 1984-1993 contained an audiogram (Swift and Singh, 1988), and none presented sequential audiograms. However, audiometry has since been published on 23 members of a family with a mitochondrial point mutation causing only sensorineural hearing loss with no other symptoms (Vernham et al., 1994). We present a case of mitochondrial cytopathy three years after diagnosis with two sequential audiograms.

Adult↗

PubMed1993

MELAS syndrome masquerading as herpes simplex encephalitis.

Herpes simplex encephalitis (HSE) is commonly treated empirically with acyclovir without confirmatory brain biopsy. Three consecutive adults with molecularly verified mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome presented with, and were treated for, apparent HSE. MELAS syndrome in adults may present as an atypical, recurrent form of HSE and should be added to the list of neurologic diseases that can mimic HSE.

Adolescent↗

PubMed1996

MELAS syndrome associated with a tandem duplication in the D-loop of mitochondrial DNA.

We describe a family with two cases of adult-onset mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. Interestingly, the proband also had non-insulin dependent diabetes mellitus and hyperthyroidism. Endocrinological studies demonstrated a high titer of TSH receptor antibody in the proband and elevated levels in her maternal relatives. Analysis of mitochondrial DNA (mtDNA) showed an A-to-G transition at nucleotide position 3243 in the tRNA (Leu(UUR)) gene (A3243G) in the three generations of the family. Furthermore, a previously described -260 bp tandem duplication in the D-loop region of mtDNA was also found in the proband and her maternal relatives. To our knowledge, such kind of duplication has never before been reported in the MELAS syndrome. The proportions of mtDNA with the -260 bp tandem duplication and A3243G point mutation were 12.5% and 82% in the muscle, respectively, and 1.6% and 35% in the blood cells, respectively, of the proband. We conclude that the hyperthyroidism in this MELAS patient may be related to the tandem duplication in the D-loop of mtDNA. This study further substantiates the importance of searching for additional genetic mutations in mitochondrial encephalomyopathic patients with new clinical phenotypes.

Adult↗

PubMed1987

Two cases of NADH-coenzyme Q reductase deficiency: relationship to MELAS syndrome.

Muscle biopsy specimens from two patients with MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) were studied biochemically. 14CO2 production rates from (1-14C)pyruvate, (U-14C)malate, and (1-14C)2-ketoglutarate were all decreased in intact mitochondria in both patients. Rotenone-sensitive NADH cytochrome c reductase activities were decreased to 8% (patient 1) and 6% (patient 2) of control values; succinate cytochrome c reductase and cytochrome c oxidase values were within normal limits. These results indicate that both patients have a defect of NADH-CoQ reductase of the respiratory chain and that MELAS can be brought about by a defect of NADH-CoQ reductase.

Acidosis, Lactic↗

PubMed1993

Ocular pathology of MELAS syndrome with mitochondrial DNA nucleotide 3243 point mutation.

PURPOSE: The authors describe the clinical, histopathologic, and ultrastructural findings in two eyes obtained at autopsy from a 21-year-old woman with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome). METHODS: The eyes were obtained immediately after death. The right eye was fixed in 10% neutral-buffered formalin and processed for standard histologic examination. The left eye was fixed in a neutral-buffered 2.5% glutaraldehyde solution and processed for transmission electron microscopic examination. The authors compared the histologic and ultrastructural findings with the clinical features recorded photographically. RESULTS: The main clinical ophthalmologic features were bilateral ptosis, chronic external ophthalmoplegia, diffuse choroidal atrophy, atypical pigmentary retinopathy with macular involvement, and patchy atrophy of the iris stroma. Molecular genetic analysis detected a tRNA Leu (UUR) point mutation at position 3243 of mitochondrial DNA (MELAS genotype). Results of histologic and ultrastructural examination showed ragged-red fibers in the rectus muscles, degeneration of photoreceptor outer segments in the macula, hyperpigmentation and atrophy of the retinal pigment epithelium of the macula, atrophy of the iris stroma, early posterior subcapsular cataract, and optic atrophy. The retinal pigment epithelium, inner segments of the photoreceptors, smooth muscle cells of the choroidal and retinal vessels, the dilator and sphincter muscle of the iris, cornea, lens epithelium, and ciliary epithelium all contained many, often enlarged, structurally abnormal mitochondria with occasional paracrystalline inclusions and circular cristae. CONCLUSIONS: The MELAS-associated mitochondrial DNA nucleotide 3243 point mutation can cause a spectrum of ocular signs and symptoms that may be dependent on the patient's age and the amount of mutant mitochondrial DNA in the tissue. MELAS syndrome should be considered in the differential diagnosis of bilateral ptosis, external ophthalmoplegia, and atypical pigmentary retinopathy with macular involvement.

Adult↗

PubMedDate not supplied

N-isopropyl-p-[123I]iodoamphetamine SPECT in MELAS syndrome: comparison with CT and MR imaging.

Regional cerebral perfusion was studied in three patients with the mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome, using single photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]iodoamphetamine (IMP). Accumulation of the tracer was relatively decreased in the parietooccipital regions and also in the frontotemporal regions after stroke-like episodes. However, quantitative regional cerebral blood flow (rCBF) measurement showed that rCBF was relatively well preserved even at these sites, and a hyperemic state was observed at the sites of normal accumulation. IMP SPECT may be useful in the diagnosis and assessment of the progress of the MELAS syndrome.

Acidosis, Lactic↗

PubMed1995

MELAS syndrome: peripheral neuropathy and cytochrome C-oxidase deficiency: a case report and review of the literature.

A 4-year-old boy presented with developmental delay, aggressive behavior, and incoordination. His EEG showed a diffuse encephalopathy. At age 10 he developed convulsions and severe migraine-like headaches. Muscle wasting, arreflexia, and lactic acidemia following exercise were noted. Electromyography was myopathic and nerve conduction studies revealed a peripheral neuropathy. Muscle biopsy demonstrated variation in fiber size and an excess of lipid droplets. He than had several stroke-like episodes and periods of unconsciousness, associated with severe metabolic acidosis. Muscle cytochrome C oxidase was abnormally low. This boy displayed the classical clinical and biochemical features of MELAS syndrome, namely Mitochondrial myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like episodes. Treatment included carnitine, vitamin C, vitamin K, riboflavin, coenzyme Q10, and corticosteroids. He died at the age of 14 years following an episode of seizures, coma, and gastrointestinal hemorrhage. This is the first reported case of MELAS syndrome in Israel.

Child, Preschool↗

PubMedDate not supplied

[MELAS syndrome: clinical, pathological and neuroimaging study].

The form of presentation of a new case of Melas Syndrome is described, together with a pathological and neuroimage study, including clinical development over a 3 year period. The usefulness of MR should be underlined here, given clinical doubts, and also normality in the EMG early phases of and the association with obstructive hypertrophic miocardiopathy.

Adolescent↗