Disaboom mitochondrialdisease

Decreased mitochondrial activity has been observed in Parkinson's disease patients.

brokenwings — Tue, 25 Mar 2008 00:53:56 GMT

Decreased mitochondrial activity has been observed in Parkinson's disease patients.

from mit.edu

Mito Symptoms

brokenwings — Tue, 25 Mar 2008 00:51:27 GMT

Mito Symptoms

from www.mda.org

MATERNAL INHERITANCE OF MITOCHONDRIAL DNA MUTATIONS

brokenwings — Tue, 25 Mar 2008 00:48:49 GMT

MATERNAL INHERITANCE OF MITOCHONDRIAL DNA MUTATIONS

Some mitochondrial encephalomyopathies that may be caused by mtDNA mutations and are subject to the rules of maternal inheritance are MERFF, MELAS, NARP, PEO and MILS.

In some syndromes, mtDNA mutations tend to occur spontaneously -- that is, the mutation isn't present in the mother or the father but has, instead, occurred very early in the development of the embryo. This is often the case for KSS, PEO and Pearson, three diseases that result from a type of mtDNA mutation called a deletion (specific portions of the DNA are missing) or mtDNA depletion (a general shortage of mtDNA). These types of spontaneously acquired mutations aren't usually passed to the next generation.

A third kind of mitochondrial disease inheritance is a combination of nuclear and mtDNA defects. This type of disease is inherited in a Mendelian fashion, indicating the involvement of a nuclear gene, but is also characterized by mtDNA deletions. In this case, the mtDNA deletions occur because there's a "breakdown in communication" between the nuclear and mitochondrial DNA.

An example of this type of disease is MNGIE. Recently, Columbia University researcher Michio Hirano and colleagues identified the nuclear gene involved in MNGIE. The gene codes for a protein called thymidine phosphorylase that may be involved in regulating the building blocks of mitochondrial DNA

Energy Extraction Process

brokenwings — Tue, 25 Mar 2008 00:45:31 GMT

Energy Extraction Process

WHAT MITOCHONDRIA DO, AND WHAT CAN GO WRONG

When the breakdown products of the food that we eat enter the mitochondria for processing, they're passed along a well-orchestrated assembly line made up of hundreds of proteins, each with a specific role to play in the energy production process. Raw materials enter the beginning of the assembly line, and ATP energy molecules come out the other side.

The major steps in the energy extraction process are (see the following illustration):

import and export of materials, such as fat and sugar derivatives, to and from the mitochondria
the breakdown of fatty acids through beta-oxidation and the removal of electrons in the citric acid cycle
the passage of electrons through the major complexes of the respiratory chain, or electron transport chain, and
the manufacture of ATP by ATP synthase.

When any one of these steps is blocked, usually because a genetic defect has prevented the manufacture of a protein required for that step, mitochondrial disease can occur. The body can't function properly because the cell's ability to make energy is reduced or stopped, and metabolic intermediates and toxic by-products begin to build up.

The energy shortage in the tissues is the major cause of muscle weakness, fatigue and problems in the heart, kidneys, eyes and endocrine system. The buildup of toxic intermediates can be responsible for liver problems, muscle cramps, brain dysfunction or even greater mitochondrial damage. Many times these two types of problems reinforce one another, each making the other worse. (The specific problems and symptoms that occur in mitochondrial disorders, and their management, will be discussed in greater detail in Part 2 of this series.)

Salvatore DiMauro, a neurologist at Columbia University in New York, says that, although there are many different types of defects that cause mitochondrial disorders, the term mitochondrial encephalomyopathy has come to refer only to disorders of the respiratory chain (numbers 3 and 4 in the illustration). (The respiratory chain is part of the cell and has nothing to do with a person's breathing.)

The respiratory chain consists of four large protein complexes: I, II, III and IV (cytochrome c oxidase, or COX), ATP synthase, and two small molecules that ferry around electrons, coenzyme Q10 and cytochrome c. The respiratory chain is the final step in the energy-making process in the mitochondrion where most of the ATP is generated; as DiMauro puts it, it's "the business end of mitochondrial metabolism." Mitochondrial encephalomyopathies that can be caused by deficiencies in one or more of the specific respiratory chain complexes include MELAS, MERFF, Leigh's syndrome, KSS, Pearson, PEO, NARP, MILS and MNGIE.

Mitochondrial Disease- how it affects the body

brokenwings — Tue, 25 Mar 2008 00:40:14 GMT

Mitochondrial Disease- how it affects the body

Mitochondria

brokenwings — Tue, 25 Mar 2008 00:37:12 GMT

Mitochondria

Mitochondria (singular mitochondrion) are the source of energy production within a cell. They are semiautonomous and self producing organelles, residing in the cytoplasm of eukaryotic cells. Converting cellular energy metabolites in the Kreb’s Cycle, through the process of oxidative phosphorylation they produce adenosine triphosphate (ATP) which is used to power other processes in the cell.

Their function is essential to efficient energy production. Without them eukaryotic cells would be dependent on anaerobic glycolysis for their ATP. Glycolysis releases very little free energy but in the mitochondria the metabolism of sugars is much more efficient and provides 15 times more ATP than is produced through glycolysis.

Mitochondria take up a large portion of the cytoplasmic volume of eukaryotic cells. They are rod shapedorganelles with an inner and an outer membrane. The outer membrane limits the organelle. The inner membrane folds in on itself forming the cristae mitochondriales, giving the appearance of partitions and chambers within the organelle in cross section. The cristae number and shape vary according to the type of tissue and organism. Cristae serve to increase the surface area of the inner membrane..

Mitochondria contain their own genome which is separate and distinct from the genome of the cell. Theoretically, mitochondria may have been separate unicellular organisms at one time and were subsumed in a symbiotic relationship into eukaryotic cells at some point in the evolutionary process.

from en.citizendium.org