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Query: UMLS:C0162671 (MELAS)
 587 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Point mutation of mitochondrial DNA has been described in the blood from a MELAS patient. The 39-year-old patient developed progressive dementia, stroke-like episodes, heart conduction defect (Lown-Ganong-Levin syndrome) and cortical blindness. CT scan revealed brain atrophy and low density areas in the bilateral occipital lobes. Laboratory tests showed hyperglycemia and lactic acidosis. Muscle biopsy showed ragged red fibers on Gomori trichrome staining. He was clinically diagnosed as having MELAS and insulin-dependent diabetes mellitus. Onset of diabetes mellitus and MELAS was almost same. Family history showed his mother's brother and sisters had also insulin-dependent diabetes mellitus. We amplified the leucine (UUR) tRNA gene from the patient's blood with polymerase chain reaction (PCR) and analysed it by restriction enzyme analysis and sequencing. Genetic analysis showed A-to-G substitution at the nucleotide position 3243 in the leucine (UUR) tRNA gene. This substitution made a new restriction site Apa I. Mutant DNA coexisted with wild type DNA (heteroplasmy). It is shown that in some types of mitochondrial encephalomyopathies, especially patients of Kearns-Sayre syndrome (KSS), diabetes mellitus is often complicated. And in KSS patients insulin receptor in normal, but insulin secretion from beta cells of pancreas is decreased. In MELAS patients, however, has diabetes mellitus been reported to be rarely complicated and relationship between MELAS and diabetes mellitus is not done. As far as we know, two cases, including ours, with genetically diagnosed MELAS have been reported to have diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[MELAS associated with diabetes mellitus and point mutation in mitochondrial DNA]. 159 Nov 3

A case of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes, in which a pituitary growth hormone (GH) secretion deficiency of hypothalamic origin was revealed through neuro-endocrinological examinations, was described. The case was a 10-year-old girl, who had been suffering from generalized tonic seizures since age 5, four episodes of alternating hemiplegia since age 6, stunted growth since age 7, and simple partial motor seizures as well as gelastic seizures since age 8. Marked elevation of lactate and pyruvate in both serum and CSF, abundant ragged red fibers in biopsied muscle, and low density areas in the left occipital lobe and bilateral globus pallidus in addition to diffuse brain atrophy on CT scan and MRI of the head were demonstrated, although the activities of muscle enzymes complex I-IV were within normal ranges. Pituitary GH secretion was deficient under the loadings with insulin, L-DOPA, sleep, and a single growth hormone releasing factor (GRF) administration, but normal GH response was registered under the repetitive stimulation with GRF. Activities of other hormonal axes were normal. It is likely that short stature commonly observed in MELAS patients is due to hypothalamic dysfunction, which might be brought out by chronic ischemia and energy deficiency of the diencephalon based upon mitochondrial abnormality of that region. It is likely that gelastic seizure in this case is due to hypothalamic dysfunction.
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PMID:[Hypothalamic GH Deficiency and gelastic seizures in a 10-year-old girl with MELAS]. 187 57

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.
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PMID:[MELAS syndrome. Clinical aspects, MRI, biochemistry and molecular genetics]. 801 33

Autopsy reports of patients with mitochondrial encephalopathy with lactic acidosis and strokelike episode (MELAS) are rare. This report documents the clinical and autopsy findings of a 47-year-old woman with MELAS syndrome. The diagnosis was corroborated by documenting a mitochondrial DNA mutation tRNA-Leu (UUR) at position 3243. The patient's clinical history was marked by schizophrenia, peptic ulcer disease, constipation requiring hemicolectomy, migraine headaches, deafness, and a left temporal lobe infarct. At autopsy, a muscle biopsy demonstrated numerous ragged red fibers and a partial cytochrome C oxidase deficiency. By electron microscopy, increased numbers of slightly hypertrophic mitochondria were observed focally within myocytes and vessel walls; paracrystalline mitochondrial inclusions were not seen. The brain at autopsy showed mild cerebral atrophy and diffuse cortical gliosis. Prominent bilateral basal ganglia calcifications and vascular sclerosis were present, and a small remote left temporal lobe infarct was seen.
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PMID:Mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) syndrome: an autopsy report. 982 26

MELAS syndrome is typically characterized by normal early development and childhood-onset recurrent neurologic deficits (stroke-like episodes), seizures, short stature, lactic acidosis, and ragged red fibers on muscle biopsy specimens. It is usually, but not invariably, associated with the A3243G point mutation in the mitochondrial DNA tRNALeu(UUR) gene. We report 3 unrelated children with the A3243G mutation who presented with severe psychomotor delay in early infancy. One patient's clinical picture was more consistent with Leigh syndrome, with apneic episodes, ataxia, and bilateral striatal lesions on brain magnetic resonance imaging (MRI). The second patient had generalized seizures refractory to treatment and bilateral occipital lesions on brain MRI. The third child had atypical retinal pigmentary changes, seizures, areflexia, and cerebral atrophy on brain MRI. All patients had several atypical features in addition to early onset: absence of an acute or focal neurologic deficit, variable serum and cerebrospinal fluid lactate levels, lack of ragged red fibers in muscle biopsy specimens. The proportion of mutant mtDNA in available tissues was relatively low (range, 5% to 51% in muscle; 4% to 39% in blood). These observations further extend the phenotypic expression of the A3243G "MELAS" mutation. Our findings confirm previous observations that there is poor correlation between abundance of mutant mtDNA in peripheral tissues and neurologic phenotype. This suggests that other factors contribute to the phenotypic expression of this mutation.
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PMID:Infantile encephalopathy associated with the MELAS A3243G mutation. 1035 36

A male infant developed progressive neuromuscular disease, hypertrophic cardiomyopathy and brain atrophy since the birth. Increased level of lactate with increased lactate/pyruvate ratio suggested a disturbance in the mitochondrial energy metabolism. The activities of respiratory chain complexes III, IV and II + III, of pyruvate dehydrogenase complex and of citrate synthase in isolated muscle mitochondria were low in comparison with controls, with parallel decrease in the content of protein amount of respiratory chain complexes III and IV. No large scale deletions of mitochondrial DNA (mtDNA) and mtDNA point mutations A3243G, A8344G or T8993G indicating syndromes MELAS, MERRF or NARP were detected. The boy died at the age of 7 weeks. The autopsy revealed typical changes of mitochondrial cardiomyopathy-marked myocardial hypertrophy with muscle pallor, histological finding of diffuse fine granularity of the cytoplasm in the perinuclear regions, and ultrastructural findings of mitochondrial hyperplasia, enlargement (megamitochondria) and abnormal shape.
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PMID:Mitochondrial cardiomyopathy--case report. 1193 62

Stroke-like lesions (SLL) are common radiological findings in patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (SLE; MELAS) harboring the m.3243A>G MTTL1 mutation. Imaging patterns in the m.3243A>G mutation carriers with encephalopathies lacking SLE have not been systematically examined to date. The aim of this study was to analyze brain imaging findings in encephalopathies associated with the m.3243A>G mutation irrespective of the presence or absence of SLE. Brain MRI and cranial CT scans from 11 m.3243A>G mutation carriers with encephalopathies were analyzed by two neuroradiologists in consensus. We evaluated stroke-like lesions (SLL), deep grey matter (DGM) changes on T1- and T2-weighted MR images, calcification on CT, brain atrophy, and white matter (WM) changes. SLL were present in all patients showing the full MELAS phenotype with SLE (4/11). Seven patients did not show SLE. DGM changes with T1 hyperintensity and T2 hypointensity were a distinctive finding in most patients (7/11) and present in the majority of m.3243A>G mutation carriers lacking SLE (5/7). DGM changes were also seen in half of our MELAS patients with SLL (2/4), though less pronounced. Brain atrophy was a prominent finding in general and accentuated in the cerebellum. In contrast, WM changes were rather mild and more prevalent and pronounced in MELAS. Our data stress that the distinction between MELAS with SLE and m.3243A>G mutation carriers lacking SLE is rather artificial. In clinical practice, mitochondrial disorders associated with the m.3243A>G mutation should be taken into consideration in encephalopathies with DGM changes, even when SLE and SLL are lacking.
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PMID:Neuroimaging characteristics in mitochondrial encephalopathies associated with the m.3243A>G MTTL1 mutation. 2319 35

Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is a rare multisystem disorder and is the most common maternally inherited mitochondrial disease. This condition has a special predilection for the nervous system and muscles. Typical findings on brain imaging include stroke-like areas, calcification of basal ganglia and brain atrophy. This accounts for the disease being, both clinically and radiologically, mistaken for ischemic stroke. The differentiation features from stroke include comparatively young age of the patients, site of the lesions, and relative overlap between the cerebral vasculature territories. In this case report, we discuss a 16-year male with clinical and radiological features highly suggestive of MELAS syndrome. Since this disease is rare and its clinical presentation is complex, it is among the most challenging to diagnose. It is particularly difficult to differentiate between ischemic stroke and MELAS. Magnetic resonance imaging (MRI) with diffusion weighted imaging (DWI), susceptibility weighted imaging (SWI) sequences and MR spectroscopy may aid in establishing the diagnosis. A particularly characteristic feature of MELAS syndrome is that recurrence may occur in locations different than previously noted, which was also seen in our patient.
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PMID:MELAS: A Complex and Challenging Diagnosis. 3135 10