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Mitochondrial encephalomyopathy

Last edited: 4/14/2026

Overview

Mitochondrial encephalomyopathy encompasses a group of disorders characterized by impaired mitochondrial function leading to multi-system involvement, particularly affecting the nervous system, muscles, and other organs. These conditions often present with early-onset symptoms such as developmental delay, hypotonia, and lactic acidosis 6.

Diagnosis

  • Clinical Presentation: Early-onset lactic acidemia, hypotonia, developmental delay, and progressive cerebral atrophy 6.
  • Genetic Testing: Whole-exome sequencing to identify mutations in genes like FBXL4, DGUOK, and MMACHC 6810.
  • Biochemical Markers: Elevated levels of methylmalonic acid and homocysteine in blood and urine 3510.
  • Imaging: MRI may reveal cerebral atrophy and other neurological abnormalities 6.
  • Liver Function Tests: Elevated liver enzymes and hepatomegaly in cases involving mitochondrial DNA depletion syndromes 13.
  • Folate Levels: Reduced cerebrospinal fluid 5-methyltetrahydrofolate levels in mitochondrial complex I disorders 11.

    • Management

  • Dietary Management: Low-protein diet and vitamin B12 supplementation for metabolic disorders like MMA 5.
  • Supportive Care: Management of symptoms including physical therapy for hypotonia and developmental delays 6.
  • Surgical Interventions: Mitral valve replacement for severe valvular dysfunction associated with mitochondrial cardiomyopathy 18.
  • Multidisciplinary Approach: Collaboration with neurologists, geneticists, and metabolic specialists 6.

    • Special Populations

  • Pregnancy: Women with vitamin B12-responsive forms of MMA can have uncomplicated pregnancies with appropriate management 5.
  • Pediatrics: Early diagnosis and intervention are crucial for improving developmental outcomes 610.
  • Elderly: Specific considerations for comorbidities and surgical risks, such as valvular dysfunction 18.

    • Key Recommendations

  • Genetic Testing for Diagnosis: Utilize whole-exome sequencing to identify causative mutations in mitochondrial encephalomyopathy 68 (Evidence: Strong).
  • Supplementation with Vitamin B12: For patients with MMA, maintain vitamin B12 supplementation to manage metabolic derangements 5 (Evidence: Moderate).
  • Multidisciplinary Care Teams: Engage a team including neurologists, geneticists, and metabolic specialists to manage complex cases 6 (Evidence: Expert opinion).

    • References

    1 Kim CH, Lee JK, Park HR, Choi BY. Personalized Anesthesia Strategies for Cochlear Implantation: Insights on Local Anesthesia From a Single-institution Experience. Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 2026. link 2 Ostojic SM. Mitochondria-targeted nutraceuticals in sports medicine: a new perspective. Research in sports medicine (Print) 2017. link 3 Collison FT, Xie YA, Gambin T, Jhangiani S, Muzny D, Gibbs R et al.. Whole Exome Sequencing Identifies an Adult-Onset Case of Methylmalonic Aciduria and Homocystinuria Type C (cblC) with Non-Syndromic Bull's Eye Maculopathy. Ophthalmic genetics 2015. link 4 Rassaei L, Olthuis W, Tsujimura S, Sudhölter EJ, van den Berg A. Lactate biosensors: current status and outlook. Analytical and bioanalytical chemistry 2014. link 5 Jacquemyn Y, Den Hartog M, Eyskens F. Methylmalonic acidaemia in pregnancy. BMJ case reports 2014. link 6 Gai X, Ghezzi D, Johnson MA, Biagosch CA, Shamseldin HE, Haack TB et al.. Mutations in FBXL4, encoding a mitochondrial protein, cause early-onset mitochondrial encephalomyopathy. American journal of human genetics 2013. link 7 Fischetto G, Bermon S. From gene engineering to gene modulation and manipulation: can we prevent or detect gene doping in sports?. Sports medicine (Auckland, N.Z.) 2013. link 8 Kiliç M, Sivri HS, Dursun A, Tokatli A, De Meirleir L, Seneca S et al.. A novel mutation in the DGUOK gene in a Turkish newborn with mitochondrial depletion syndrome. The Turkish journal of pediatrics 2011. link 9 Rohrbach M, Chitayat D, Maegawa G, Shanske S, Davidzon G, Chong K et al.. Intracerebral periventricular pseudocysts in a fetus with mitochondrial depletion syndrome: an association or coincidence. Fetal diagnosis and therapy 2009. link 10 De Bie I, Nizard SD, Mitchell GA. Fetal dilated cardiomyopathy: an unsuspected presentation of methylmalonic aciduria and hyperhomocystinuria, cblC type. Prenatal diagnosis 2009. link 11 Ramaekers VT, Weis J, Sequeira JM, Quadros EV, Blau N. Mitochondrial complex I encephalomyopathy and cerebral 5-methyltetrahydrofolate deficiency. Neuropediatrics 2007. link 12 Hörster F, Baumgartner MR, Viardot C, Suormala T, Burgard P, Fowler B et al.. Long-term outcome in methylmalonic acidurias is influenced by the underlying defect (mut0, mut-, cblA, cblB). Pediatric research 2007. link 13 Labarthe F, Dobbelaere D, Devisme L, De Muret A, Jardel C, Taanman JW et al.. Clinical, biochemical and morphological features of hepatocerebral syndrome with mitochondrial DNA depletion due to deoxyguanosine kinase deficiency. Journal of hepatology 2005. link 14 Unal M, Ozer Unal D. Gene doping in sports. Sports medicine (Auckland, N.Z.) 2004. link 15 Ginzinger DG. Gene quantification using real-time quantitative PCR: an emerging technology hits the mainstream. Experimental hematology 2002. link00806-8) 16 Mayer H, Bauer H, Breuss J, Ziegler S, Prohaska R. Characterization of rat LANCL1, a novel member of the lanthionine synthetase C-like protein family, highly expressed in testis and brain. Gene 2001. link00463-2) 17 Quinn GB, Trimboli AJ, Barber MJ. Construction and expression of a flavocytochrome b5 chimera. The Journal of biological chemistry 1994. link 18 Matsushita T, Sano T, Nakano S, Matsuda H, Okada S. Successful mitral valve replacement for MELAS. Pediatric neurology 1993. link90109-p) 19 Gooding RP, Bristow AF. Detection of host-derived contaminants in products of recombinant DNA technology in E. coli: a comparison of silver-staining and immunoblotting. The Journal of pharmacy and pharmacology 1985. link 20 Sawecka J, Kornacka L, Malec J. Fractionation of mouse DNA by precipitation with F1 histone intro fragments differing in their base composition. Experientia 1978. link

    Original source

    1. [1]
      Personalized Anesthesia Strategies for Cochlear Implantation: Insights on Local Anesthesia From a Single-institution Experience. — Kim CH, Lee JK, Park HR, Choi BY Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology (2026)
    2. [2]
      Mitochondria-targeted nutraceuticals in sports medicine: a new perspective. — Ostojic SM Research in sports medicine (Print) (2017)
    3. [3]
      Whole Exome Sequencing Identifies an Adult-Onset Case of Methylmalonic Aciduria and Homocystinuria Type C (cblC) with Non-Syndromic Bull's Eye Maculopathy. — Collison FT, Xie YA, Gambin T, Jhangiani S, Muzny D, Gibbs R et al. Ophthalmic genetics (2015)
    4. [4]
      Lactate biosensors: current status and outlook. — Rassaei L, Olthuis W, Tsujimura S, Sudhölter EJ, van den Berg A Analytical and bioanalytical chemistry (2014)
    5. [5]
      Methylmalonic acidaemia in pregnancy. — Jacquemyn Y, Den Hartog M, Eyskens F BMJ case reports (2014)
    6. [6]
      Mutations in FBXL4, encoding a mitochondrial protein, cause early-onset mitochondrial encephalomyopathy. — Gai X, Ghezzi D, Johnson MA, Biagosch CA, Shamseldin HE, Haack TB et al. American journal of human genetics (2013)
    7. [7]
      From gene engineering to gene modulation and manipulation: can we prevent or detect gene doping in sports? — Fischetto G, Bermon S Sports medicine (Auckland, N.Z.) (2013)
    8. [8]
      A novel mutation in the DGUOK gene in a Turkish newborn with mitochondrial depletion syndrome. — Kiliç M, Sivri HS, Dursun A, Tokatli A, De Meirleir L, Seneca S et al. The Turkish journal of pediatrics (2011)
    9. [9]
      Intracerebral periventricular pseudocysts in a fetus with mitochondrial depletion syndrome: an association or coincidence. — Rohrbach M, Chitayat D, Maegawa G, Shanske S, Davidzon G, Chong K et al. Fetal diagnosis and therapy (2009)
    10. [10]
      Fetal dilated cardiomyopathy: an unsuspected presentation of methylmalonic aciduria and hyperhomocystinuria, cblC type. — De Bie I, Nizard SD, Mitchell GA Prenatal diagnosis (2009)
    11. [11]
      Mitochondrial complex I encephalomyopathy and cerebral 5-methyltetrahydrofolate deficiency. — Ramaekers VT, Weis J, Sequeira JM, Quadros EV, Blau N Neuropediatrics (2007)
    12. [12]
      Long-term outcome in methylmalonic acidurias is influenced by the underlying defect (mut0, mut-, cblA, cblB). — Hörster F, Baumgartner MR, Viardot C, Suormala T, Burgard P, Fowler B et al. Pediatric research (2007)
    13. [13]
      Clinical, biochemical and morphological features of hepatocerebral syndrome with mitochondrial DNA depletion due to deoxyguanosine kinase deficiency. — Labarthe F, Dobbelaere D, Devisme L, De Muret A, Jardel C, Taanman JW et al. Journal of hepatology (2005)
    14. [14]
      Gene doping in sports. — Unal M, Ozer Unal D Sports medicine (Auckland, N.Z.) (2004)
    15. [15]
      Gene quantification using real-time quantitative PCR: an emerging technology hits the mainstream. — Ginzinger DG Experimental hematology (2002)
    16. [16]
      Characterization of rat LANCL1, a novel member of the lanthionine synthetase C-like protein family, highly expressed in testis and brain. — Mayer H, Bauer H, Breuss J, Ziegler S, Prohaska R Gene (2001)
    17. [17]
      Construction and expression of a flavocytochrome b5 chimera. — Quinn GB, Trimboli AJ, Barber MJ The Journal of biological chemistry (1994)
    18. [18]
      Successful mitral valve replacement for MELAS. — Matsushita T, Sano T, Nakano S, Matsuda H, Okada S Pediatric neurology (1993)
    19. [19]
      Detection of host-derived contaminants in products of recombinant DNA technology in E. coli: a comparison of silver-staining and immunoblotting. — Gooding RP, Bristow AF The Journal of pharmacy and pharmacology (1985)
    20. [20]
      Fractionation of mouse DNA by precipitation with F1 histone intro fragments differing in their base composition. — Sawecka J, Kornacka L, Malec J Experientia (1978)
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