Types
Examples of mitochondrial diseases include:

Mitochondrial myopathy
Diabetes mellitus and deafness (DAD)
this combination at an early age can be due to mitochondrial disease
Diabetes mellitus and deafness can be found together for other reasons
Lebers 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
affects 1 in 50,000 people in Finland
Leigh syndrome, subacute necrotizing encephalomyelopathyafter 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
MERRF syndrome
progressive myoclonic epilepsy
"Ragged Red Fibers" are clumps of diseased mitochondria that accumulate in the subsarcolemmal region of the muscle fiber and appear when muscle is stained with modified Gömöri trichrome stain
short stature
hearing loss
lactic acidosis
exercise intolerance
MELAS syndrome
Mitochondrial DNA depletion syndromeConditions such as Friedreichs ataxia can affect the mitochondria but are not associated with mitochondrial proteins. Presentation
Associated conditions
Acquired conditions in which mitochondrial dysfunction has been involved are:

diabetes
Huntingtons disease
cancer
Alzheimers disease,
Parkinsons disease
bipolar disorder, schizophrenia, aging and senescence, anxiety disorders
cardiovascular disease
sarcopenia
chronic fatigue syndromeThe body, and each mutation, is modulated by other genome variants; the mutation that in one individual may cause liver disease might in another person cause a brain disorder. The severity of the specific defect may also be great or small. Some defects include exercise intolerance.
Defects in nuclear-encoded mitochondrial genes are associated with hundreds of clinical disease phenotypes including anemia, dementia, hypertension, lymphoma, retinopathy, seizures, and neurodevelopmental disorders.A study by Yale University researchers (published in the February 12, 2004, issue of the New England Journal of Medicine) explored the role of mitochondria in insulin resistance among the offspring of patients with type 2 diabetes. Other studies have shown that the mechanism may involve the interruption of the mitochondrial signaling process in body cells (intramyocellular lipids). A study conducted at the Pennington Biomedical Research Center in Baton Rouge, Louisiana showed that this, in turn, partially disables the genes that produce mitochondria. Mechanisms
The effective overall energy unit for the available body energy is referred to as the daily glycogen generation capacity, and is used to compare the mitochondrial output of affected or chronically glycogen-depleted individuals to healthy individuals. This value is slow to change in a given individual, as it takes between 18 and 24 months to complete a full cycle.The glycogen generation capacity is entirely dependent on, and determined by, the operating levels of the mitochondria in all of the cells of the human body; however, the relation between the energy generated by the mitochondria and the glycogen capacity is very loose and is mediated by many biochemical pathways. The energy output of full healthy mitochondrial function can be predicted exactly by a complicated theoretical argument, but this argument is not straightforward, as most energy is consumed by the brain and is not easily measurable.