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At least 19 recordsLinked to original sources
PubMed2004

Cochlear implantation in patients with MELAS syndrome.

MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) is a rare congenital disorder of mitochondrial DNA (mt-DNA). Patients with this syndrome may present to the otolaryngologist with sensorineural hearing loss (SNHL) that is genetic in origin. Mitochondrial cytopathies can present with a variety of symptoms, but they occasionally present with SNHL as their first manifestation. Two cases of MELAS patients who responded well to cochlear implantation are presented. A review of the literature is also carried out focusing mainly on diagnosis, anesthetic considerations and management of these patients.

Adult↗
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↗
PubMed1999

Increased prevalence of vitiligo, but no evidence of premature ageing, in the skin of patients with bp 3243 mutation in mitochondrial DNA in the mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes syndrome (MELAS).

The MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes) belongs to the category of mitochondrial disorders. The most common molecular aetiology of the syndrome is a mutation at base pair (bp) 3243 in the mitochondrial genome (mtDNA). The phenotype is varied and, apart from central nervous system involvement, the patients with this mutation may present with neurosensory hearing loss, diabetes mellitus and cardiomyopathy. These phenotypes suggest that organs dependent on aerobic metabolism suffer most. We investigated the possible clinical and physiological manifestations of impaired energy metabolism in the skin of 28 patients with the bp 3243 mutation in mtDNA. Non-invasive sonography and laser Doppler flowmetry were used to measure skin thickness and the blood flow of the skin. Skin collagen synthesis was assayed from suction blister fluid. Evaporimetry was used to assess the re-epithelialization rate of suction blister wounds. Histochemistry and immunohistochemistry were used to evaluate the melanocytes and pigment in the skin. Vitiligo was found in three of the 28 patients (11%), which was markedly more than in the general population. Histological findings showed an absence of pigment, but an apparently normal distribution of melanocytes in the dermoepidermal junction. Seborrhoeic eczema and atopy were also somewhat more frequent. No features of premature ageing, such as a marked decrease in skin thickness, blood flow, collagen synthesis or re-epithelialization rate, were demonstrated.

Adult↗
PubMed2005

Precipitation of stroke-like event by chickenpox in a child with MELAS syndrome.

The mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) is a rare congenital disorder of mitochondrial DNA (mtDNA). Herein we report a case of MELAS, whose second stroke-like episode was provoked by chickenpox. A point mutation at nucleotide (nt) 3243 in mtDNA supported the diagnosis of MELAS in this case. History of myopathy, the presence of lesions that did not conform to accepted distributions of vascular territories on cranial magnetic resonance imaging (MRI), normal result of cranial magnetic resonance angiography, hyperintensity on diffusion weighted MRI and apparent diffusion coefficient mapping indicating the presence of vasogenic edema in the fresh stroke-like lesion, and mitochondrial DNA analysis helped to exclude the diagnosis of ischemic cerebral infarction which can also be induced by chickenpox.

Chickenpox↗
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↗
PubMed2004

Prenatal diagnosis of a fetus harboring an intermediate load of the A3243G mtDNA mutation in a maternal carrier diagnosed with MELAS syndrome.

We prenatally diagnosed MELAS syndrome in a fetus whose mother and older brother had the MELAS-specific A3243G mutation. The mutant mtDNA level of the amniotic fluid cells was not significantly different from that of the postnatal peripheral blood and hair follicle samples. The obstetrical course was uncomplicated except for transient exacerbation of the mother's diabetes, which required insulin control. At term, the infant was macrosomic, and the delivery was complicated by shoulder dystocia. MELAS syndrome in itself does not influence either the prenatal course of the mother or the fetal outcome. In contrast to the fulminating clinical course of this mother's first child, MELAS symptoms did not develop in her second child until age four, despite similar high tissue levels of mutant mtDNA. The phenotypic diversity in two offspring with similar higher levels of mutant mtDNA suggests that prenatal genetic diagnosis of cultured amniotic cells may yield results that are poor prognosticators of fetal outcome.

Adult↗
PubMedDate not supplied

[MELAS syndrome masquerading as herpes encephalitis: genetic diagnosis].

INTRODUCTION: MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke like episodes) is a mitochondrial disease related to the mitochondrial DNA mutation. The tRNALeu(UUR) mutation at the base pair 3234 is associated to 80% of cases of MELAS syndrome. The onset with the stroke like episodes is often before the age 40. Herpes simplex encephalitis (HSE) presents as acute episodes of focal neurologic deficit that are often related to the temporal lobe. Occasionally MELAS syndrome and HSE may have a similar clinical presentation. CLINICAL CASE: A 33-year-old woman presented with seizures and a right parietotemporal syndrome of acute onset. The differential diagnosis between HSE and MELAS syndrome was established. MELAS syndrome was suspected based on her phenotype. The diagnosis of MELAS syndrome was confirmed by the presence of the mitochondrial tRNALeu(UUR) mutation at the base pair 3243. CONCLUSION: The clinical presentation of the MELAS syndrome may mimic that of the HSE, and antiviral treatment should be given until the diagnosis of MELAS syndrome is definitive. The study of the mitochondrial DNA helps diagnosing in a non invasive way many patients with MELAS syndrome.

Acute Disease↗
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↗
PubMed2002

Diversity of clinical symptoms in A3243G mitochondrial DNA mutation (MELAS syndrome mutation).

BACKGROUND: MELAS (mitochondrial myopathy, lactic acidosis and stroke-like episodes) is one of the most common mitochondrial encephalomyopathies. MATERIAL/METHODS: We present four children with A3243G MELAS mtDNA mutation and give a summary of clinical MELAS symptoms reported in the literature. Serum lactate elevation, mosaic pattern of COX deficit and decreased activity of complex I and IV in the muscle biopsy were found in all cases. RRFs were recognized in three out of four. RESULTS: The main features seen in all our patients were poor growth and fatigability with muscle weakness. All presented epileptic jerks of various character, some deformation features (recurrent pretibial and peritarsal edema, large swollen-looking hands and feet, hypertelorism and protruding ears) and some cutaneous lesions (atopic dermatitis, local melanoderma, asymmetric vascular dilatation). Stroke-like episodes, multihormonal hypopituitarism, sensorineural hypoacusis, pigmentary retinal degeneration, intracranial calcification, heart involvement, recurrent vomiting or abdominal pain were seen only in individual cases. The homonymous hemianopia frequently reported in the literature was not a feature of our patients. One of them suffered from nonspecific sialoadenitis never mentioned in the literature. CONCLUSIONS: Morphological, enzymatic and molecular investigations of a muscle biopsy sample should be undertaken to improve early MELAS detection in patients with any multiorgan disease associated with serum lactate elevation.

Age of Onset↗
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↗
PubMed2001

[MELAS syndrome (mitochondrial encephalopathy with lactic acidosis and stroke-like episodes].

BACKGROUND: The MELAS syndrome (Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-like episodes) belongs to the category of mitochondrial disorders. The most common molecular etiology of the syndrome is a mutation A to G transition at base pair 3243 in the mitochondrial genome. The phenotype is varied and depends on the proportion of DNA muted and which organ on aerobic metabolism suffers most. CASE-REPORT: An 17 year-old woman had successively neurosensory hearing loss, renal disease, cardiomyopathy, diabetes mellitus, lactic acidosis and stroke-like episodes that evoked a MELAS syndrome. DISCUSSION: The skin manifestations of patients with MELAS syndrome are scaly, pruritic, diffuse erythema, reticular pigmentation, moderate hypertrichosis, seborrheic eczema, atopy and vitiligo. Our patient presented severe hirsutism and reticular pigmentation of the limbs. No abnormal histologic and electron microscopic findings were noted in the skin or the follicles involved.

Adolescent↗
PubMed1999

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.

Adult↗
PubMed2006

The mitochondrial myopathy encephalopathy, lactic acidosis with stroke-like episodes (MELAS) syndrome: a review of treatment options.

Mitochondrial encephalomyopathies are a multisystemic group of disorders that are characterised by a wide range of biochemical and genetic mitochondrial defects and variable modes of inheritance. Among this group of disorders, the mitochondrial myopathy, encephalopathy, lactic acidosis with stroke-like episodes (MELAS) syndrome is one of the most frequently occurring, maternally inherited mitochondrial disorders. As the name implies, stroke-like episodes are the defining feature of the MELAS syndrome, often occurring before the age of 15 years. The clinical course of this disorder is highly variable, ranging from asymptomatic, with normal early development, to progressive muscle weakness, lactic acidosis, cognitive dysfunction, seizures, stroke-like episodes, encephalopathy and premature death. This syndrome is associated with a number of point mutations in the mitochondrial DNA, with over 80% of the mutations occurring in the dihydrouridine loop of the mitochondrial transfer RNA(Leu(UUR)) [tRNA(Leu)((UUR))] gene. The pathophysiology of the disease is not completely understood; however, several different mechanisms are proposed to contribute to this disease. These include decreased aminoacylation of mitochondrial tRNA, resulting in decreased mitochondrial protein synthesis; changes in calcium homeostasis; and alterations in nitric oxide metabolism. Currently, no consensus criteria exist for treating the MELAS syndrome or mitochondrial dysfunction in other diseases. Many of the therapeutic strategies used have been adopted as the result of isolated case reports or limited clinical studies that have included a heterogeneous population of patients with the MELAS syndrome, other defects in oxidative phosphorylation or lactic acidosis due to disorders of pyruvate metabolism. Current approaches to the treatment of the MELAS syndrome are based on the use of antioxidants, respiratory chain substrates and cofactors in the form of vitamins; however, no consistent benefits have been observed with these treatments.

Humans↗
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↗