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Myoadenylate deaminase deficiency
Myoadenylate deaminase deficiency (MADD) is a recessive genetic metabolic disorder that affects approximately 1-2% of populations of European descent (making it a not particularly "rare" rare disease). It appears to be considerably rarer in Oriental populations.
Additional recommended knowledge
Myoadenylate deaminase, also called AMP deaminase, is an enzyme that converts adenosine monophosphate (AMP) to inosine monophosphate (IMP), freeing an ammonia molecule in the process. It is a part of the metabolic process that converts sugar, fat, and protein into cellular energy. In order to use energy, a cell converts one of the above fuels into adenosine triphosphate (ATP) via the mitochondria. Cellular processes, especially muscles, then convert the ATP into adenosine diphosphate (ADP), freeing the energy to do work.
In some cases (such as greater than normal energy demand), other enzymes then convert two molecules of ADP into one ATP molecule and one AMP molecule, making more ATP available to supply energy. The resulting AMP molecule is not normally recycled directly, but is converted into IMP by myoadenylate deaminase. If myoadenylate deaminase is deficient, excess AMP builds up in the cell and is eventually transported by the blood to liver to be metabolized or to the kidneys to be excreted.
Effects of failure to deaminate the AMP molecules
This failure to deaminate the AMP molecules has three major effects. First, significant amounts of AMP are lost from the cell and the body. Second, ammonia is not freed when the cell does work. Third, the level of IMP in the cell is not maintained.
Symptomatic relief from the effects of MADD may sometimes be achieved by administering ribose orally at a dose of approximately 10 grams per 100 pounds (0.2 g/kg) of body weight per day.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Myoadenylate_deaminase_deficiency". A list of authors is available in Wikipedia.|