Mitochondrial Disorders
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Mitochondrial disorders
Abstract:
Mitochondria is a sub-cellular organelles or semi autonomous organelle, 90% of energy creating by mitochondria that is needed by the body to assist life and support to growth.MD(mitochondrial disorder) caused by mutations in mitochondrial DNA or in the nuclear gene. AUTOSOMAL and maternal inheritance is involved in mitochondrial disorder. MD is a source of reactive oxygen species (ROS).oxidative stress is one potential path mechanism for mitochondrial disease. Mitochondrial disorder is LEIGH disease, mitochondrial MYOPATHY and diabetes mellitus deafness. Therapeutic strategies are used to overcome the mitochondrial disorders by enhancing biogenesis and electron transport chain function.
Introduction:
It is a sub-cellular organelles or semi autonomous organelle, 90% of energy creating by mitochondria that is needed by the body to assist life and support to growth. It is said that mitochondrial function as ‘energy factories’ for the cell. It involves in supplying cellular energy and also involves cell processes such as adaptive thermo genesis innate immune responses reactive oxygen species production, ion homeostasis and programmed cell death (apoptosis).mitochondrion is made by 3000 genes. Just 37 0f genes are in coded by mitochondrion DNA. The remaining genes encoded by cell nucleus .to making ATP only 3 % of the genes are required which are allocated in the mitochondrion. Rate limiting enzymes for pyrimidine biosynthesis (dihydrorotate, dehydrogenase) and hem synthesis (d-amino levulinic acid aynthetase) are present in mitochondria which make haemoglobin. (salvatore dimauro, guido davidzon et al)
About 50 years ago a single patient was suffering hyper metabolism in which there was a mitochondrial defect .then the mitochondrial diseases develop gradually by its own genetic rules. Now these disorders considered most common among inherited diseases .mitochondrial diseases mostly damage to cell of brain, kidney skeletal muscle heart and respiratory and endocrine system. Mitochondrial disorders result from dysfunction of respiratory chain .if there is a reduction of enzyme function in one or more five respiratory chain complexes then mutation occurs. (herodotos ellinas, elizabeth a.m. frost et al). It is the group of disorders which is caused by dysfunctional mitochondria. It is the organelle which is powerhouse of the cell. The disorders are caused by mutations which affect mitochondrial function. Mitochondrial respiratory chain disorders are very severe. It is group of genetically and clinically heterogeneous disease. It may b inherited from mitochondrial DNA or from nuclear DNA or may be caused by spontaneous mutation. Mitochondrion is not found in RBC.
GENOCOPIES of mitochondrial disorders:
In different tissue mitochondria perform different function. There are many different disorders. Each disorder show different abnormalities. It can be difficult to physicians in early stages of diagnosis. GENOCOPIES disorder are those that is caused by the same mutation but which may not look the same clinically.
PHENOCOPIES of mitochondrial disease
The converse is also true same disease have different mutation in MTDNA and NDNA. In genetics, these are called PHENOCOPIES.
Aging and other factors:
Mitochondrial disorders are more complex in adults because detectable changes occur in mtDNA with age. The aging process itself may result from decline mitochondrial function. In adults abnormal mitochondrial function has been proved in inherited metabolic and acquired disorders. The disorder is growth retardation.
Brain
Nerves
Muscles
Kidneys
*developmental delays
*dementia
*migraines
*seizures
*mental retardation
*storks
*neuro-psychiatric disturbances
*weakness (may be intermittent)
*fainting
*absent reflexes
*neuropathic pain
*dysautonomic-temperature instability & dys autonomic problems
*weakness
*irritable bowl syndrome
*cramping
*dysmotility
*muscle pain
*hypotonia
*diarrhoea or constipation
*pseudo-obstruction
*rental tubular acidosis or wasting
Table 1: shows different abnormalities due to mitochondrial disorder (aging).
Heart
Liver
Ears & eye
Systemic
*cardiac reduction
*cardiomyopathy
Defects (heart blocks)
*hypoglycemia
(low blood sugar)
*liver failure
*posies
*hearing loss &
Deafness
*optic atrophy
*visual loss and
Blindness
*fatigue
*failure to gain weight
*vomiting
*short stature
*respiratory