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MELAS  -  mitochondrial encephalomyopathy, lactic...

Homo sapiens

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Disease relevance of MELAS


Psychiatry related information on MELAS


High impact information on MELAS

  • Individuals with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) carry a common A-to-G substitution in a highly conserved portion of the gene for transfer RNA(Leu(UUR)) [9].
  • Impairment of mitochondrial transcription termination by a point mutation associated with the MELAS subgroup of mitochondrial encephalomyopathies [9].
  • Although the MELAS mutation may be comparable to the defect in the tRNA(Lys) gene associated with MERRF (myoclonus epilepsy associated with ragged-red fibres), it is also embedded in the middle of a tridecamer sequence necessary for the formation of the 3' ends of 16S ribosomal RNA in vitro [9].
  • This suggests that the molecular defect in MELAS is the inability to produce the correct type and quantity of rRNA relative to other mitochondrial gene products [9].
  • The presence of carcinogenic and mutagenic chemical(s) in the effluent of a wastewater treatment plant was indicated by papillomas developing on caged black bullheads (Ictalurus melas), hepatic enzyme induction in exposed fish, and Ames test mutagenicity of organic extracts of the wastewater [10].

Chemical compound and disease context of MELAS


Biological context of MELAS


Anatomical context of MELAS


Associations of MELAS with chemical compounds

  • Yet another pattern of regional metabolic abnormality was present in the MELAS syndrome, where proton spectroscopic imaging demonstrated focal localization of abnormally increased lactate/creatine and decreased N-acetylaspartate/creatine to the regions of the stroke-like lesions on conventional MR images [26].
  • Cerebral perfusion reserve was obtained from 6 patients (3 MELAS, 1 MERRF, 1 KSS, 1 CCOD) for a comparative analysis using the split-dose 123I-IMP SPECT method before and after the injection of acetazolamide [24].
  • Treatment of MELAS, LHON, and MERRF cells with cyclosporin A caused significant rescue from oxidant exposure, and in each case significantly greater rescue of mutant than control cells [27].
  • Pyruvate dehydrogenase complex deficiency and altered respiratory chain function in a patient with Kearns-Sayre/MELAS overlap syndrome and A3243G mtDNA mutation [11].
  • The patients with this mutation did not have cerebro-muscular symptoms as were observed in MELAS [28].

Physical interactions of MELAS

  • A novel mtDNA mutation in the ND5 subunit of complex I in two MELAS patients [29].
  • We report a novel point mutation in the gene for the mitochondrially encoded ND6 subunit of the NADH:ubiquinone oxidoreductase (complex I of the respiratory chain) in a patient with MELAS syndrome [30].
  • The MELAS mutation occurs within the mtDNA binding site for a protein factor (mTERF) that promotes termination of transcription at the 16S rRNA/tRNA(LeuUUR) gene boundary [31].

Other interactions of MELAS


Analytical, diagnostic and therapeutic context of MELAS

  • The decreased cerebral perfusion reserve in patients with MELAS may represent an important feature of the pathogenesis of the strokelike episodes [24].
  • In spite of the small number of cases in each group, in Alpers, MERRF and MELAS syndromes we found sequential EEG patterns which seemed to be typical of the respective syndromes [35].
  • We here report Southern blot analyses in the cases of CPEO we have seen and describe the search for point mutations in MELAS and MERRF [36].
  • CONCLUSION: These data suggest that a prenatal diagnosis for MELAS syndrome might be helpful for at-risk families [37].
  • Decrease of 3243 A-->G mtDNA mutation from blood in MELAS syndrome: a longitudinal study [38].


  1. A mutation in the tRNA(Leu)(UUR) gene associated with the MELAS subgroup of mitochondrial encephalomyopathies. Goto, Y., Nonaka, I., Horai, S. Nature (1990) [Pubmed]
  2. A new disease-related mutation for mitochondrial encephalopathy lactic acidosis and strokelike episodes (MELAS) syndrome affects the ND4 subunit of the respiratory complex I. Lertrit, P., Noer, A.S., Jean-Francois, M.J., Kapsa, R., Dennett, X., Thyagarajan, D., Lethlean, K., Byrne, E., Marzuki, S. Am. J. Hum. Genet. (1992) [Pubmed]
  3. Cardiac involvement in mitochondrial diseases. A study on 17 patients with documented mitochondrial DNA defects. Anan, R., Nakagawa, M., Miyata, M., Higuchi, I., Nakao, S., Suehara, M., Osame, M., Tanaka, H. Circulation (1995) [Pubmed]
  4. HMPAO-SPECT imaging resembling Alzheimer-type dementia in mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). Grünwald, F., Zierz, S., Broich, K., Schumacher, S., Bockisch, A., Biersack, H.J. J. Nucl. Med. (1990) [Pubmed]
  5. Familial occurrence of intestinal obstruction in children with the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). Shimotake, T., Furukawa, T., Inoue, K., Iwai, N., Takeuchi, Y. J. Pediatr. Surg. (1998) [Pubmed]
  6. Therapeutic effect of sodium dichloroacetate on visual and auditory hallucinations in a patient with MELAS. Saijo, T., Naito, E., Ito, M., Takeda, E., Hashimoto, T., Kuroda, Y. Neuropediatrics. (1991) [Pubmed]
  7. Aggressive confusional state as a clinical manifestation of status epilepticus in MELAS. Feddersen, B., Bender, A., Arnold, S., Klopstock, T., Noachtar, S. Neurology (2003) [Pubmed]
  8. Mitochondrial DNA sequence analysis of patients with 'atypical psychosis'. Kazuno, A.A., Munakata, K., Mori, K., Tanaka, M., Nanko, S., Kunugi, H., Umekage, T., Tochigi, M., Kohda, K., Sasaki, T., Akiyama, T., Washizuka, S., Kato, N., Kato, T. Psychiatry and clinical neurosciences. (2005) [Pubmed]
  9. Impairment of mitochondrial transcription termination by a point mutation associated with the MELAS subgroup of mitochondrial encephalomyopathies. Hess, J.F., Parisi, M.A., Bennett, J.L., Clayton, D.A. Nature (1991) [Pubmed]
  10. Papillomas on fish exposed to chlorinated wastewater effluent. Grizzle, J.M., Melius, P., Strength, D.R. J. Natl. Cancer Inst. (1984) [Pubmed]
  11. Pyruvate dehydrogenase complex deficiency and altered respiratory chain function in a patient with Kearns-Sayre/MELAS overlap syndrome and A3243G mtDNA mutation. Wilichowski, E., Korenke, G.C., Ruitenbeek, W., De Meirleir, L., Hagendorff, A., Janssen, A.J., Lissens, W., Hanefeld, F. J. Neurol. Sci. (1998) [Pubmed]
  12. Strongly succinate dehydrogenase-reactive blood vessels in muscles from patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes. Hasegawa, H., Matsuoka, T., Goto, Y., Nonaka, I. Ann. Neurol. (1991) [Pubmed]
  13. Effects of dichloroacetate in three patients with MELAS. Saitoh, S., Momoi, M.Y., Yamagata, T., Mori, Y., Imai, M. Neurology (1998) [Pubmed]
  14. Mutations of the mitochondrial genome: clinical overview and possible pathophysiology of cell damage. Rothman, S.M. Biochem. Soc. Symp. (1999) [Pubmed]
  15. Cerebral hyperemia in MELAS. Gropen, T.I., Prohovnik, I., Tatemichi, T.K., Hirano, M. Stroke (1994) [Pubmed]
  16. Defects in mitochondrial protein synthesis and respiratory chain activity segregate with the tRNA(Leu(UUR)) mutation associated with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes. King, M.P., Koga, Y., Davidson, M., Schon, E.A. Mol. Cell. Biol. (1992) [Pubmed]
  17. Mitochondrial DNA and RNA processing in MELAS. Kaufmann, P., Koga, Y., Shanske, S., Hirano, M., DiMauro, S., King, M.P., Schon, E.A. Ann. Neurol. (1996) [Pubmed]
  18. The mitochondrial DNA G13513A transition in ND5 is associated with a LHON/MELAS overlap syndrome and may be a frequent cause of MELAS. Pulkes, T., Eunson, L., Patterson, V., Siddiqui, A., Wood, N.W., Nelson, I.P., Morgan-Hughes, J.A., Hanna, M.G. Ann. Neurol. (1999) [Pubmed]
  19. Is the mitochondrial complex I ND5 gene a hot-spot for MELAS causing mutations? Liolitsa, D., Rahman, S., Benton, S., Carr, L.J., Hanna, M.G. Ann. Neurol. (2003) [Pubmed]
  20. Mitochondrial DNA expression in mitochondrial myopathies and coordinated expression of nuclear genes involved in ATP production. Heddi, A., Lestienne, P., Wallace, D.C., Stepien, G. J. Biol. Chem. (1993) [Pubmed]
  21. Advanced telomere shortening in respiratory chain disorders. Oexle, K., Zwirner, A. Hum. Mol. Genet. (1997) [Pubmed]
  22. Neuropathy associated with mitochondrial disorders. Schröder, J.M. Brain Pathol. (1993) [Pubmed]
  23. Quantification of OXPHOS gene transcripts during muscle cell differentiation in patients with mitochondrial myopathies. Bonod-Bidaud, C., Giraud, S., Mandon, G., Mousson, B., Stepien, G. Exp. Cell Res. (1999) [Pubmed]
  24. SPECT findings in mitochondrial encephalomyopathy. Watanabe, Y., Hashikawa, K., Moriwaki, H., Oku, N., Seike, Y., Kodaka, R., Ono, J., Uehara, T., Kusuoka, H., Nishimura, T. J. Nucl. Med. (1998) [Pubmed]
  25. Identification of a novel mutation in the mtDNA ND5 gene associated with MELAS. Santorelli, F.M., Tanji, K., Kulikova, R., Shanske, S., Vilarinho, L., Hays, A.P., DiMauro, S. Biochem. Biophys. Res. Commun. (1997) [Pubmed]
  26. Proton MR spectroscopic characterization of differences in regional brain metabolic abnormalities in mitochondrial encephalomyopathies. Mathews, P.M., Andermann, F., Silver, K., Karpati, G., Arnold, D.L. Neurology (1993) [Pubmed]
  27. mtDNA mutations confer cellular sensitivity to oxidant stress that is partially rescued by calcium depletion and cyclosporin A. Wong, A., Cortopassi, G. Biochem. Biophys. Res. Commun. (1997) [Pubmed]
  28. Mitochondrial gene mutations that affect the binding of the termination factor and their prevalence among Japanese diabetes mellitus. Odawara, M., Asano, M., Yamashita, K. Nucleic Acids Symp. Ser. (1995) [Pubmed]
  29. A novel mtDNA mutation in the ND5 subunit of complex I in two MELAS patients. Corona, P., Antozzi, C., Carrara, F., D'Incerti, L., Lamantea, E., Tiranti, V., Zeviani, M. Ann. Neurol. (2001) [Pubmed]
  30. An mtDNA mutation, 14453G-->A, in the NADH dehydrogenase subunit 6 associated with severe MELAS syndrome. Ravn, K., Wibrand, F., Hansen, F.J., Horn, N., Rosenberg, T., Schwartz, M. Eur. J. Hum. Genet. (2001) [Pubmed]
  31. MELAS mutation in mtDNA binding site for transcription termination factor causes defects in protein synthesis and in respiration but no change in levels of upstream and downstream mature transcripts. Chomyn, A., Martinuzzi, A., Yoneda, M., Daga, A., Hurko, O., Johns, D., Lai, S.T., Nonaka, I., Angelini, C., Attardi, G. Proc. Natl. Acad. Sci. U.S.A. (1992) [Pubmed]
  32. A novel combination of mitochondrial tRNA and ND1 gene mutations in a syndrome with MELAS, cardiomyopathy, and diabetes mellitus. Jaksch, M., Hofmann, S., Kaufhold, P., Obermaier-Kusser, B., Zierz, S., Gerbitz, K.D. Hum. Mutat. (1996) [Pubmed]
  33. No association of ALDH2 genotype in MELAS. Suzuki, Y., Muramatsu, T., Taniyama, M., Goto, Y., Oka, Y., Suzuki, S., Tsukuda, K., Atsumi, Y., Nonaka, I., Hosokawa, K., Shimada, A., Asahina, T., Matsuoka, K. Diabetologia (1997) [Pubmed]
  34. Mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes: a distinctive clinical syndrome. Pavlakis, S.G., Phillips, P.C., DiMauro, S., De Vivo, D.C., Rowland, L.P. Ann. Neurol. (1984) [Pubmed]
  35. EEG findings in children and adolescents with mitochondrial encephalomyopathies: a study of 25 cases. Tulinius, M.H., Hagne, I. Brain Dev. (1991) [Pubmed]
  36. The molecular genetics of mitochondrial cytopathies: the Melbourne experience. Thyagarajan, D., Byrne, E., Dennet, X., Marzuki, S. Clinical and experimental neurology. (1992) [Pubmed]
  37. Prenatal diagnosis of myopathy, encephalopathy, lactic acidosis, and stroke-like syndrome: contribution to understanding mitochondrial DNA segregation during human embryofetal development. Bouchet, C., Steffann, J., Corcos, J., Monnot, S., Paquis, V., R??tig, A., Lebon, S., Levy, P., Royer, G., Giurgea, I., Gigarel, N., Benachi, A., Dumez, Y., Munnich, A., Bonnefont, J.P. J. Med. Genet. (2006) [Pubmed]
  38. Decrease of 3243 A-->G mtDNA mutation from blood in MELAS syndrome: a longitudinal study. Rahman, S., Poulton, J., Marchington, D., Suomalainen, A. Am. J. Hum. Genet. (2001) [Pubmed]
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