GTR Home > Conditions/Phenotypes > Mitochondrial diseases

Summary

Excerpted from the GeneReview: Mitochondrial Disorders Overview
Mitochondrial diseases are a clinically heterogeneous group of disorders that arise as a result of dysfunction of the mitochondrial respiratory chain. They can be caused by mutation of genes encoded by either nuclear DNA or mitochondrial DNA (mtDNA). While some mitochondrial disorders only affect a single organ (e.g., the eye in Leber hereditary optic neuropathy [LHON]), many involve multiple organ systems and often present with prominent neurologic and myopathic features. Mitochondrial disorders may present at any age. Many individuals with a mutation of mtDNA display a cluster of clinical features that fall into a discrete clinical syndrome, such as the Kearns-Sayre syndrome (KSS), chronic progressive external ophthalmoplegia (CPEO), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy with ragged-red fibers (MERRF), neurogenic weakness with ataxia and retinitis pigmentosa (NARP), or Leigh syndrome (LS). However, considerable clinical variability exists and many individuals do not fit neatly into one particular category, which is well-illustrated by the overlapping spectrum of disease phenotypes (including mitochondrial recessive ataxia syndrome (MIRAS) resulting from mutation of the nuclear gene POLG, which has emerged as a major cause of mitochondrial disease. Common clinical features of mitochondrial disease – whether involving a mitochondrial or nuclear gene – include ptosis, external ophthalmoplegia, proximal myopathy and exercise intolerance, cardiomyopathy, sensorineural deafness, optic atrophy, pigmentary retinopathy, and diabetes mellitus. Common central nervous system findings are fluctuating encephalopathy, seizures, dementia, migraine, stroke-like episodes, ataxia, and spasticity. A high incidence of mid- and late pregnancy loss is a common occurrence that often goes unrecognized.

Genes See tests for all associated and related genes

  • Also known as: MTND1, ND1
    Summary: mitochondrially encoded NADH dehydrogenase 1

  • Also known as: MTND4, ND4
    Summary: mitochondrially encoded NADH dehydrogenase 4

  • Also known as: MTND5, ND5
    Summary: mitochondrially encoded NADH dehydrogenase 5

  • Also known as: MTND6, ND6
    Summary: mitochondrially encoded NADH dehydrogenase 6

  • Also known as: MTTA, TRNA
    Summary: mitochondrially encoded tRNA alanine

  • Also known as: MTTC, TRNC
    Summary: mitochondrially encoded tRNA cysteine

  • Also known as: MTTD, TRND
    Summary: mitochondrially encoded tRNA aspartic acid

  • Also known as: , TRNF
    Summary: mitochondrially encoded tRNA phenylalanine

  • Also known as: MTTH, TRNH
    Summary: mitochondrially encoded tRNA histidine

  • Also known as: MTTK, TRNK
    Summary: mitochondrially encoded tRNA lysine

  • Also known as: MTTL1, TRNL1
    Summary: mitochondrially encoded tRNA leucine 1 (UUA/G)

  • Also known as: MTTL2, TRNL2
    Summary: mitochondrially encoded tRNA leucine 2 (CUN)

  • Also known as: MTTM, TRNM
    Summary: mitochondrially encoded tRNA methionine

  • Also known as: MTTQ, TRNQ
    Summary: mitochondrially encoded tRNA glutamine

  • Also known as: MTTR, TRNR
    Summary: mitochondrially encoded tRNA arginine

  • Also known as: MTTS1, TRNS1
    Summary: mitochondrially encoded tRNA serine 1 (UCN)

  • Also known as: MTTS2, TRNS2
    Summary: mitochondrially encoded tRNA serine 2 (AGU/C)

  • Also known as: MTTT, TRNT
    Summary: mitochondrially encoded tRNA threonine

  • Also known as: MTTV, TRNV
    Summary: mitochondrially encoded tRNA valine

  • Also known as: MTTW, TRNW
    Summary: mitochondrially encoded tRNA tryptophan

  • Also known as: MTTY, TRNY
    Summary: mitochondrially encoded tRNA tyrosine

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