- Myoadenylate deaminase deficiency
Name = PAGENAME
OMIM = 102770
Myoadenylate deaminase deficiency (MADD) is a
recessivegenetic metabolic disorderthat affects approximately 1-2% of populations of European descent (making it a not particularly "rare" rare disease). It appears to be considerably rarer in Asian populations.
Myoadenylate deaminase, also called
AMP deaminase, is an enzymethat converts adenosine monophosphate (AMP) to inosine monophosphate(IMP), freeing an ammoniamolecule in the process. It is a part of the metabolic processthat converts sugar, fat, and proteininto 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
bloodto liverto 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.
* The first effect -- the loss of AMP -- is mostly significant because AMP contains
ribose, a sugar molecule that is also used to make DNA, RNA, and some enzymes. Though the body can manufacture some ribose and obtain more from RNA-rich sources such as beans and red meat, this loss of ribose due to MADD is sometimes sufficient to create a shortage in the body, resulting in symptoms of severe fatigue and muscle pain. This outcome is especially likely if the individual regularly exercises vigorously over a period of weeks or months.
* The second effect, the absence of ammonia, is not well understood. It may result in a reduction of the amount of
fumarateavailable to the citric acid cycle, and it may result in lower levels of nitric oxide(a vasodilator) in the body, reducing blood flow and oxygenintake during vigorous exercise.
* The third effect, the reduction in IMP, is also not well understood. It may somehow result in a reduction in the amount of
lactic acidproduced by the muscles.
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.
* [http://www.neuro.wustl.edu/neuromuscular/mother/mpain.html#mad Overview at wustl.edu]
Wikimedia Foundation. 2010.
Look at other dictionaries:
myoadenylate deaminase deficiency — myo·ad·en·yl·ate de·am·i·nase de·fi·cien·cy (mi″o adґən əl āt de amґĭ nās) a mild autosomal recessive disorder caused by mutation in the AMPD1 gene (locus: 1p21 p13), which encodes the muscle isoform of AMP… … Medical dictionary
Adenosine Monophosphate Deaminase Deficiency type 1 — Classification and external resources Adenosine monophosphate OMIM 102770 … Wikipedia
AMP deaminase — Adenosine monophosphate deaminase 1 Identifiers Symbols AMPD1; MAD; MADA External IDs … Wikipedia
AMP deaminase — An enzyme hydrolyzing adenylic acid to inosinic acid and NH3. A deficiency of A. in muscles can lead to excess fatigue following exercise. SYN: adenylic acid deaminase. * * * AMP de·am·i·nase (de amґĭ nās) [EC 22.214.171.124] an enzyme of the… … Medical dictionary
List of diseases (M) — A list of diseases in the English wikipedia.DiseasesTOC MaMac* Mac Ardle disease * Mac Dermot Patton Williams syndrome * Mac Dermot Winter syndromeMaci Macr* Macias Flores Garcia Cruz Rivera syndrome * Mackay Shek Carr syndrome * Macleod Fraser… … Wikipedia
Rhabdomyolysis — Classification and external resources Urine from a person with rhabdomyolysis showing the characteristic brown discoloration as a result of myoglobinuria … Wikipedia
Myoadenylatdeaminase — Der Myoadenylatdeaminase Mangel (Myoadenylate Deaminase Deficiency, MADD) ist der häufigste erbliche Stoffwechseldefekt der Skelettmuskulatur, dessen klinische Bedeutung seit der Erstbeschreibung 1978 umstritten ist. Inhaltsverzeichnis 1… … Deutsch Wikipedia
Myoadenylatdeaminase-Mangel — Der Myoadenylatdeaminase Mangel (Myoadenylate Deaminase Deficiency, MADD) ist der häufigste erbliche Stoffwechseldefekt der Skelettmuskulatur, dessen klinische Bedeutung seit der Erstbeschreibung 1978 umstritten ist. Inhaltsverzeichnis 1… … Deutsch Wikipedia
Myoadenylatdesaminase-Mangel — Der Myoadenylatdesaminase Mangel (MAD Mangel, Myoadenylate Deaminase Deficiency, MADD) ist der häufigste erbliche Stoffwechseldefekt der Skelettmuskulatur, dessen klinische Bedeutung seit der Erstbeschreibung 1978 umstritten ist.… … Deutsch Wikipedia
MADD — is an abbreviation for: *Mothers Against Drunk Driving *Myoadenylate deaminase deficiency A metabolic disorder *Multiple acyl CoA dehydrogenation deficiency another name for the genetic disorder Glutaric acidemia type 2 … Wikipedia