Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162671 (MELAS)
 587 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in cerebral white matter at CT or MRI have been reported in patients with migraine, especially in those with migraine with aura. Similar pictures may be present in asymptomatic subjects, and their nature is not completely understood, but their infarct-like nature is strongly suggested. Clinicians play an important role in the evaluation of those migraine patients in whom these nonspecific abnormalities are present. We suggest ruling out specific syndromes in which migraine attacks are associated with white matter changes (CADASIL, MELAS, multiple sclerosis and central nervous system vasculitis), as well as evaluating the presence of different vascular risk factors (genetic prothrombotic factors, patent foramen ovale, use of oral contraceptives, etc.). Their possible causative role in MRI lesions and in enhancing the risk of a negative clinical evolution must be considered in each individual case.
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PMID:The role of the clinician in interpreting conventional neuroimaging findings in migraine patients. 1750 56

Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is an autosomal recessive disorder caused by mutations in ORNT1 gene that encodes a mitochondrial ornithine transporter. It has variable clinical presentations with episodic hyperammonemia, liver dysfunction, and chronic neurological manifestations. In this work, we report the findings of HHH syndrome in 3 Saudi siblings. The 4-year-old proband presented with recurrent Reye-like episodes, hypotonia, and multiple stroke-like lesions on brain MRI. Biochemical and molecular analysis confirmed that she had HHH syndrome. She significantly improved on protein restriction and sodium benzoate. Her two older siblings have milder phenotypes with protein intolerance and learning problems. In comparison to their sister, their homocitrulline and orotic acid were only mildly elevated even before treatment. The three patients were homozygous for a novel mutation in ORNT1 with a Gly220Arg change. In view of the CNS lesions, which initially were felt to be suggestive of MELAS, we sequenced the entire mtDNA genome and no potential pathogenic mutations were detected. Analysis of ORNT2 did not provide explanation of the clinical and biochemical variability. This work presents a yet unreported CNS involvement pattern, notably multiple supratentorial stroke-like lesions in association with HHH syndrome. Moreover, it illustrates considerable clinical/biochemical correlation, and describes a novel mutation. We suggest including HHH syndrome in the differential diagnosis of patients found to have stroke-like lesions on brain MRI.
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PMID:Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome with stroke-like imaging presentation: clinical, biochemical and molecular analysis. 1782 24

A case is reported of a 20-year-old female presenting with confusion and progressive sensory aphasia. CT and MRI showed bilateral and symmetric acute necrosis of the basal ganglia and of the left temporal and occipital lobe, besides chronic spinocerebellar degeneration. The imaging findings suggested a mitochrondrial encephalopathy. Genetic examination confirmed a MELAS syndrome (mitochondrial myopathy, encephalopathy, lactate acidosis and stroke like episodes).
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PMID:CT and MRI appearance of mitochondrial encephalopathy. 1796 48

Although linked with cardiac dysfunction, the association of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) and pulmonary artery hypertension (PAH) has not been previously described. PAH and right ventricular heart failure were identified by echocardiography in a 3-year-old boy with a history of hypotonia, microcephaly and developmental delay. He initially presented with a 10-day history of dyspnoea, dependent oedema and reduced oral intake. Lactic acidosis was noted on serial arterial blood sampling and cerebrospinal fluid. Muscle biopsy demonstrated cytochrome-c oxidase-positive 'ragged-red' fibres consistent with MELAS; subsequent analyses revealed the m.3243A>G point mutation most commonly associated with MELAS. The mutation was heteroplasmic, representing 92% of the total mtDNA from a lung sample. Nitric oxide and epoprostenol were administered without significant clinical or echocardiographic improvement of his PAH. A 'mitochondrial cocktail' including biotin, riboflavin, carnitine and coenzyme Q10 also was provided. Five months after presentation, he developed seizures; MRI imaging of his brain demonstrated multiple focal lesions. His clinical status worsened with increasing cardiopulmonary failure. He died two months later. Although therapy for both MELAS and PAH remains limited, recent investigations suggest a beneficial role for l-arginine in both conditions, implying a possible common pathophysiology. Mitochondrial diseases such as MELAS should be considered in cases of idiopathic PAH, particularly when associated with multisystem involvement including short stature, hearing loss, renal dysfunction, retinopathy, diabetes mellitus, migraines, seizures, ophthalmoplegia, fatigability and weakness.
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PMID:Pulmonary artery hypertension in a child with MELAS due to a point mutation of the mitochondrial tRNA((Leu)) gene (m.3243A>G). 1818 Oct 29

The mitochondrial 13513G>A (D393N) mutation in the ND5 subunit of the respiratory chain complex I was initially described in association with MELAS syndrome. Recent observations have linked this mutation to Leigh disease. We screened for the 13513G>A mutation in a cohort of 265 patients with Leigh and Leigh-like disease. The mutation was found in a total of 5 patients. An additional patient who had clinical presentation consistent with a Leigh-like phenotype but with a normal brain MRI was added to the cohort. None of an additional 88 patients meeting MELAS disease criteria, nor 56 patients with respiratory chain deficiency screened for the 13513G>A were found positive for the mutation. The most frequent clinical manifestations in our patients were hypotonia, ocular and cerebellar involvement. Low mutation heteroplasmy in the range of 20-40% was observed in all 6 patients. This observation is consistent with the previously reported low heteroplasmy of this mutation in some patients with the 13513G>A mutation and complex I deficiency. However, normal complex I activity was observed in two patients in our cohort. As most patients with Leigh-like disease and the 13513G>A mutation have been described with complex I deficiency, this report adds to the previously reported subset of patients with normal respiratory complex function. We conclude that in any patient with Leigh or Leigh-like disease, testing for the 13513G>A mutation is clinically relevant and low mutant loads in blood or muscle may be considered pathogenic, in the presence of normal respiratory chain enzyme activities.
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PMID:The mitochondrial 13513G>A mutation is associated with Leigh disease phenotypes independent of complex I deficiency in muscle. 1849 10

Mitochondrial disorders, in particular respiratory chain diseases (RCDs), present either as single organ problem or as multi-system disease. One of the most frequently affected organs in RCDs, in addition to the skeletal muscle, is the central nervous system (CNS). CNS manifestations of RCDs include epilepsy, stroke-like episodes, migraine-like headache, ataxia, spasticity, movement disorders, psychosis, demyelination, calcification, but also dementia. Cognitive impairment may be a feature of syndromic as well as non-syndromic RCDs. Syndromic RCDs associated with cognitive impairment include MELAS, KSS, Leigh syndrome, and many others. RCDs with cognitive decline not only result from mtDNA mutations but also from mutations in nuclear genes. At onset there is often no general intellectual deterioration in these patients but specific cognitive deficits, particularly in the visual construction, attention, abstraction, or flexibility. Diagnosis of cognitive impairment from RCDs is based on neuropsychological testing, imaging studies, including MRI, PET, SPECT, or MR-spectroscopy, CSF investigations, or electroencephalography. Therapeutic strategies for dementia in RCDs rely on symptomatic measures. Only single patients may profit from cholinesterase inhibitors or memantine, antioxidants, vitamins, or other substitutes. Overall, cognitive decline in RCDs (mitochondrial dementia) needs to be included in the differentials of dementia.
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PMID:Cognitive decline as a manifestation of mitochondrial disorders (mitochondrial dementia). 1857 95

A case of visual hallucination, headache and left hemiparesis is reported. The patient had a history of recurrent attacks of similar semiology for the previous 15 years. MRI brain revealed a cortical hyperintensity on T2W, FLAIR and diffusion weighted imaging (DWI) in the right cerebral hemisphere with a normal ADC (apparent diffusion coefficient) map and MR angiogram. Detailed workup for MELAS was negative. A diagnosis of sporadic hemiplegic migraine was made and he was managed conservatively. He made a gradual complete recovery over 2 weeks. He was discharged on flunarizine for prophylaxis and has remained asymptomatic over the ensuing 4 months. This interesting condition is reviewed and discussed herein.
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PMID:Sporadic hemiplegic migraine: report of a case with clinical and radiological features. 1881 Mar 16

MELAS is commonly associated with peripheral hearing loss. Auditory agnosia is a rare cortical auditory impairment, usually due to bilateral temporal damage. We document, for the first time, auditory agnosia as the presenting hearing disorder in MELAS. A young woman with MELAS (A3243G mtDNA mutation) suffered from acute cortical hearing damage following a single stroke-like episode, in the absence of previous hearing deficits. Audiometric testing showed marked central hearing impairment and very mild sensorineural hearing loss. MRI documented bilateral, acute lesions to superior temporal regions. Neuropsychological tests demonstrated auditory agnosia without aphasia. Our data and a review of published reports show that cortical auditory disorders are relatively frequent in MELAS, probably due to the strikingly high incidence of bilateral and symmetric damage following stroke-like episodes. Acute auditory agnosia can be the presenting hearing deficit in MELAS and, conversely, MELAS should be suspected in young adults with sudden hearing loss.
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PMID:Acute auditory agnosia as the presenting hearing disorder in MELAS. 1901 35

The organ most frequently affected in mitochondrial disorders, particularly respiratory chain diseases (RCDs), in addition to the skeletal muscle, is the central nervous system (CNS). CNS manifestations of RCDs comprise stroke-like episodes, epilepsy, migraine, ataxia, spasticity, movement disorders, psychiatric disorders, cognitive decline, or even dementia (mitochondrial dementia). So far mitochondrial dementia has been reported in MELAS, MERRF, LHON, CPEO, KSS, MNGIE, NARP, Leigh syndrome, and Alpers-Huttenlocher disease. Mitochondrial dementia not only results from mutations in the mitochondrial genome but also from mutations in nuclear genes, such as POLG, thymidine kinase 2, or DDP1. Often mitochondrial dementia starts with specific cognitive deficits, particularly in visual construction, attention, abstraction, or flexibility but without a general intellectual deterioration. Cognitive impairment in RCDs is diagnosed upon neuropsychological testing, imaging studies, such as MRI, PET, or MR-spectroscopy, CSF-investigations, or electroencephalography. Therapy of mitochondrial dementia relies on symptomatic measures. Only single patients profit from cholinesterase inhibitors or memantine, antioxidants, vitamins, coenzyme-Q, or other substitutes. Overall, mitochondrial dementia is an important differential of dementias and should be considered in patients with multi-system disease.
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PMID:Mitochondrial disorders, cognitive impairment and dementia. 1926 75

Cytochrome c oxidase (COX) is the terminal enzyme of the respiratory chain, with subunits originating both from the mitochondrial and nuclear genome. An eleven-year-old female presented initially with a seizure followed two months later with tonic-clonic seizures, weakness and aphasia. MRI of the cerebral hemispheres showed multiple infarcts. Previous history suggested gross and fine motor control deficits with learning difficulties. A muscle biopsy showed a specific decrease of COX staining in all fibres and pleomorphic mitochondria. Respiratory chain studies confirmed an isolated complex IV defect in muscle, whilst fibroblasts showed an initial COX activity below normal which rapidly came up to the normal range on culture. Sequencing of mtDNA revealed an heteroplasmic m.7023G>A mutation in the COX1 gene, with levels of 96% in muscle, 70% in blood and 50% in the initial skin fibroblast culture dropping to 10% in later passages. The mutation was present in a critical region of the COX1 gene, the V374M change being close to the two histidine residues His376 and His378 co-ordinating with the heme a and a (3), and His367 which co-ordinates a magnesium ion. This case highlights that a MELAS-like syndrome can occur with isolated COX deficiency.
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PMID:A novel mitochondrial DNA mutation in COX1 leads to strokes, seizures, and lactic acidosis. 1956 96


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