Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q96FX7 (tRNA)
 26,753 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The A 3243 G mutation of the mitochondrial tRNA(Leu) gene was found to segregate with maternally inherited diabetes mellitus, sensorineural deafness, hypertrophic cardiomyopathy, or renal failure in a large pedigree of 35 affected members in four generations. Presenting symptoms almost consistently involved deafness and recurrent attacks of migraine-like headaches, but the clinical course of the disease varied within and across generations. The A 3243 G mutation has been previously reported in association with the mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episode syndrome (MELAS) and with diabetes mellitus and deafness. To our knowledge, however, hypertrophic cardiomyopathy is not a common feature in people with the A 3243 G mutation and renal failure has not been hitherto reported in association with this mutation. The present observation gives additional support to the variable clinical expression of mtDNA mutations in humans.
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PMID:Point mutation of the mitochondrial tRNA(Leu) gene (A 3243 G) in maternally inherited hypertrophic cardiomyopathy, diabetes mellitus, renal failure, and sensorineural deafness. 747 62

A case of mitochondrial encephalomyopathy with lactic acidosis, a stroke-like episode (MELAS) without ragged red fiber, diagnosed by mitochondrial DNA testing, is reported. A 37-year-old woman experienced a sudden and recurrent headache with vomiting and stroke-like episodes. Brain CT and MRI showed multiple infarction in the temporal lobes, not corresponding to artery distribution. However, the plasma levels of lactate and pyruvate were normal, and showed no increased after aerobic exercise. Biopsied muscle showed no evidence of ragged red fibers and deficient activity of mitochondrial enzymes in the respiratory chain. The final diagnosis was made by mitochondrial DNA testing. A southern blot analysis after Apa I digestion revealed the A-to-G mutation in the tRNA(Leu(UUR)), which is specific to MELAS.
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PMID:MELAS without ragged red fibers or lactic acidosis diagnosed by mitochondrial DNA testing. 830 80

We reviewed 10 patients (5 males, 5 females) with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The age of symptom onset ranged from 3 months to 12 years. All had lactic acidosis, multiple stroke-like events with secondary neurological deficits, radiological changes of progressive brain infarction, and muscle biopsy showing ragged-red fibers. In patients with earlier onset of symptoms (< 2 yr), involvement tended to be more diffuse, with failure to thrive and early onset of delayed development. Patients whose symptoms appeared later tended to have focal neurological deficits with migraine-like headache, and a rate of cognitive regression reflecting the rapidity of disease progression. Radiological changes included multiple areas of infarction with initial predilection for parietal occipital areas, progressing to generalized atrophy. Pathological findings in muscle biopsies included type 1 fiber predominance, ragged-red fibers, increased intermyofibrillar lipid deposition, and abnormal mitochondria. Four patients showed mitochondrial DNA tRNA mutation at position 3,243. No difference was noted in clinical, radiological, or pathological findings in patients with and without this mutation, suggesting that multiple sites of point mutation may give rise to mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes.
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PMID:Mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS): clinical, radiological, pathological, and genetic observations. 851 76

Various mutations in the mitochondrial tRNA(Leu)(UUR) gene give rise to a variety of neurological disorders. Among these, mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS syndrome) are frequently associated with a tRNA(Leu)(UUR) mutation at nucleotide position 3243 of the mitochondrial DNA. A supplementary clinical feature seen in these patients is headache in early life. Recently, a tRNA(Leu)(UUR) mutation at nucleotide position 3243 has been found in a patient presenting with cluster headache. This led us to examine the mitochondrial genomes of 22 patients presenting with cluster headache. None of the patients harboured the reported tRNA(Leu)(UUR) mutation or any other length variations of the mtDNA. Cluster headache is most likely not causally associated with the A3243G mutation of the mitochondrial DNA.
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PMID:Investigation on the mitochondrial transfer RNA(Leu)(UUR) in blood cells from patients with cluster headache. 896 1

A 25-year-old man developed nausea, vomiting, severe headache, and confusion. He had a past history of hyperuricemia and mild renal dysfunction. On admission he had somatic growth retardation, hypertrichosis, and bilateral auditory impairment. A cranial CT scan showed a small area of low density in the left temporal lobe and cerebellar atrophy. Five days later, he developed right homonymous hemianopia, sensory aphasia, and sensory inattention, and a new, large area of low density in the left occipital lobe on a cranial CT scan. On laboratory examination, lactate, pyruvate, and the lactate-to-pyruvate ratio were elevated in both the serum and cerebrospinal fluid. The biopsied muscle showed ragged red fibers and strongly SDH-reactive blood vessels. Gene analysis revealed the presence of the A 3243 G point mutation of the mitochondrial tRNA(Leu) gene in his blood leucocytes and muscle. Serum concentrations of BUN and creatinine were elevated to 46 mg/dl and 2.2 mg/dl, respectively. Creatinine clearance was 14.1 ml/min. An abdominal CT scan disclosed atrophy of his left kidney with subcapsular calcification and the findings of his abdominal ultrasonography were compatible with chronic renal failure. His mother, who suffered from renal failure and became dialysis dependent in her late forties also bore the A 3243 G mutation of the mitochondrial tRNA(Leu) gene in her circulating leucocytes. Though the association between MELAS and renal dysfunction still remains obscure, we speculate that renal failure can be a manifestation of MELAS.
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PMID:[Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) with chronic renal failure: report of mother-child cases]. 897 30

Diabetes mellitus associated with mitochondrial tRNA mutation at position 3243(DM-Mt3243) is a new disease. Patients have a distinctly different picture from MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). During observations at the Saiseikai Central Hospital, the following findings were noted in DM-Mt3243 patients: DM-Mt3243 patients are diagnosed earlier with diabetes, compared to NIDDM (non-insulin dependent diabetes mellitus) controls without family history. DM-Mt3243 patients often need insulin more often than NIDDM controls without family history. Post-treatment neuropathy and insulin edema are often found in DM-Mt3243, and the two phenomena possibly have a similar pathophysiology related to mitochondrial dysfunction. Ambiguous psychiatric disorders of functional psychosis are observed frequently in DM-Mt3243. Mild headache is common in DM-Mt3243 cases. Ambiguous neuromuscular abnormalities such as sleep disturbance, paresthesia of the legs, edema of the legs, and palpitation may be symptoms associated with mitochondrial dysfunction in DM-Mt3243. Coenzyme Q may be effective in the relief of these neuromuscular symptoms.
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PMID:Diabetes mellitus associated with 3243 mitochondrial tRNA(Leu(UUR)) mutation: clinical features and coenzyme Q10 treatment. 926 20

The authors describe a patient who presented with headache, seizures, and severe cerebral edema in whom they identified a novel mutation in the mitochondrial (mt-) tRNA(His) gene. This G12147A transition is heteroplasmic, predicted to disrupt a highly conserved base pair, and segregates with the cytochrome c oxidase deficiency in single muscle fibers.
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PMID:Catastrophic presentation of mitochondrial disease due to a mutation in the tRNA(His) gene. 1511 88

Ten patients with migraine with prolonged aura were studied for the presence of mitochondrial DNA point mutations utilizing DNA isolated from blood and hair samples. We analyzed for nine point mutations reported in patients with MELAS (A3243G, C3256T, T3271C, T3291C, A5814G, T8356C, T9957C, G13513A, and A13514G) and three secondary LHON mutations (T4216C, A4917G, and G13708A). None of the patients tested had any of these mutations in mitochondrial DNA. However, one patient was found to have a tRNA(Gln) A4336G mitochondrial DNA variant. From this study it appears that migraine with prolonged aura is not an oligosymptomatic form of MELAS and is not related to secondary LHON mutations. The significance of the tRNA A4336G variant is unknown.
Headache
PMID:Study of mitochondrial DNA mutations in patients with migraine with prolonged aura. 1520 89

Brain single photon emission computed tomography (SPECT) studies were conducted in three patients with A3243G mutation of the mitochondrial (mt) DNA tRNA. All were born to mothers suffering from chronic progressive external ophthalmoplegia (CPEO) with the same A3243G point mutation of the mtDNA tRNA. The first case manifested clinically with MELAS, the second case manifested with CPEO, and third case was characterized by recurrent migraine-like headache, tremor, and epilepsy. Brain SPECT of all patients, regardless of whether they had or had not suffered from stroke-like episodes, showed multiple areas of asymmetrical decreased perfusion, particularly in the posterior and lateral head regions, especially the temporal lobes. Crossed-cerebellar diaschisis may occur. Conventional brain magnetic resonance images failed to show some of the lesions. Decreased regional cerebral blood flow, rather than previously proposed hyperemia, is likely to be the cause. We conclude that mitochondrial vasculopathy with regional cerebral hypoperfusion may be seen on brain SPECT in patients with mitochondrial disorders and A3243G mutations, regardless of whether they have or have not suffered from stroke-like episodes.
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PMID:Brain single photon emission computed tomography in patients with A3243G mutation in mitochondrial DNA tRNA. 1596 44

We report herein the case of a 28-year-old man presenting with hyperglycemic chorea-ballism (HCB) in addition to mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). He was admitted to a local hospital due to weight loss, general fatigue and thirst. The patient had diabetes mellitus, with a blood glucose level of 738 mg/dl and HbA1c of 19.8%. Although insulin therapy improved hyperglycemia, he noticed involuntary movements in the right upper and lower limbs, which subsequently extended to the left side. The patient was thus transferred to our hospital. He displayed short stature (154 cm) and emaciation, and a maternal family history of diabetes mellitus was elicited. He had no history of stroke-like episode, headache, vomiting and seizure. Neurological examination revealed low intelligence (IQ 57), mild sensorineural deafness, and chorea-ballism in the extremities and head without ptosis or eye movement disturbance. Brain computed tomography (CT) demonstrated areas of high density, while T1-weighted magnetic resonance imaging (MRI) revealed extreme hyperintensity and T2-weighted MRI showed hyperintensity in bilateral caudate nuclei, putamina and globi pallidus. HCB was diagnosed. In, CSF, lactate level was increased to 43.9 mg/dl (n, 4-16), pyruvate level was 1.65 mg/dl (n, 0.3-0.9) and total protein concentration was 59 mg/dl. Histological examination of a biopsy sample from the biceps brachii muscle demonstrated ragged-red fibers. An A3243G point mutation in the tRNA(Leu(UUR)) gene was detected, indicating the presence of MELAS. Involuntary movements improved on treatment with haloperidol up to 4.5 mg/day. HCB usually appears in elderly individuals, and cases less than 40-years-old are very rare. The mitochondrial dysfunction in MELAS may accelerate development of HCB.
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PMID:[A case of MELAS presenting juvenile-onset hyperglycemic chorea-ballism]. 1611 32


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