Mitochondrial Disease - Classification

Classification

In addition to the mitochondrial myopathies, other examples include:

• Diabetes mellitus and deafness (DAD)
  • this combination at an early age can be due to mitochondrial disease
  • Diabetes mellitus and deafness can also be found together for other reasons
• Leber's hereditary optic neuropathy (LHON)
  • visual loss beginning in young adulthood
  • eye disorder characterized by progressive loss of central vision due to degeneration of the optic nerves and retina
  • Wolff-Parkinson-White syndrome
  • multiple sclerosis-type disease
  • affects 1 in 50,000 people in Finland
• Leigh syndrome, subacute sclerosing encephalopathy
  • after normal development the disease usually begins late in the first year of life, although onset may occur in adulthood
  • a rapid decline in function occurs and is marked by seizures, altered states of consciousness, dementia, ventilatory failure
• Neuropathy, ataxia, retinitis pigmentosa, and ptosis (NARP)
  • progressive symptoms as described in the acronym
  • dementia
• Myoneurogenic gastrointestinal encephalopathy (MNGIE)
  • gastrointestinal pseudo-obstruction
  • neuropathy
• Myoclonic Epilepsy with Ragged Red Fibers (MERRF)
  • progressive myoclonic epilepsy
  • "Ragged Red Fibers" – clumps of diseased mitochondria accumulate in the subsarcolemmal region of the muscle fiber and appear as "Ragged Red Fibers" when muscle is stained with modified Gömöri trichrome stain
  • short stature
  • hearing loss
  • lactic acidosis
  • exercise intolerance
• Mitochondrial myopathy, encephalomyopathy, lactic acidosis, stroke-like symptoms (MELAS)
• mtDNA depletion
  • mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)

Nota bene: Conditions such as Friedreich's ataxia can affect the mitochondria, but are not associated with mitochondrial proteins.