rouadefoc
Forum Senior
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Posts: 109
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The gene defect for 5-Oxoprolinuria is an autosomal recessive genetic trait
Synonyms:
* Pyroglutamic Aciduria
* Pyroglutamicaciduria
5-Oxoprolinuria is a biochemical finding that can arise from two underlying metabolic disorders. It is characterized by excretion of massive amounts of the chemical 5-oxoproline.
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| pawan.dr
Forum Junior
Topics: 5
Posts: 26
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disha where did u come up with tht one?? never heard of it....
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| tolito
Forum Fanatic
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what is the clinical importance of it??
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| tolito
Forum Fanatic
Topics: 119
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searched and found following
http://www.clinchem.org/cgi/content/full/44/2/336
or a shorter one http://www.idph.state.il.us/HealthWellness/fs/5ox...
5-Oxoprolinuria (pyroglutamic aciduria) is a condition characterized by increased production and urinary excretion of 5-oxoproline. Its presence is associated with inborn errors in the synthesis and metabolism of glutathione, a tripeptide found in most tissues that is essential for a variety of detoxification, antioxidant, and stabilizing functions. These inborn errors consist of defects in the  -glutamyl cycle, a series of enzyme-linked reactions involved in the synthesis, metabolism, and transcellular transport of glutathione. Such rare defects or deficiencies have been described for most of the enzymes involved in the cycle, but those involving glutathione synthetase and 5-oxoprolinase are of particular clinical interest. An inherited deficiency of either of these two enzymes results in an increased production and plasma concentration of 5-oxoproline that is reflected as an increase in urinary excretion (5-oxoprolinuria). These conditions have been demonstrated previously to be inherited in an autosomal recessive manner.glutathione synthetase is involved in the conversion of -glutamyl cysteine to glutathione. A block here, therefore, leads to reduced amounts of glutathione production and marked accumulation of -glutamyl cysteine, not only because its conversion to glutathione is blocked, but also because its production is increased because of the lifting of the negative feedback that glutathione concentrations have on the enzyme -glutamyl cysteine synthetase. This accumulation of -glutamyl cysteine does not, however, persist, because it is converted via a less favorable alternative pathway by the enzyme -glutamyl cyclotransferase back to 5-oxoproline, which is only slowly utilized forward through the cycle by the rate-limiting enzyme 5-oxoprolinase; hence, marked accumulation of 5-oxoproline persists.
Clinically, this disorder manifests as a direct result of increased amounts of 5-oxoproline and a deficiency of glutathione. Increased 5-oxoproline causes a severe high anion gap metabolic acidosis, usually presenting at birth, and is a major cause of early mortality; the glutathione deficiency, then, is linked to the development of hemolytic anemia, defective leukocyte function, and a variety of progressive neurological sequelae ranging from mental retardation to motor disturbances that develop variably over the years, if indeed the affected individuals survive the neonatal period.
some cases of apparently induced states of 5-oxoprolinuria without any evidence of inherited metabolic defects in the -glutamyl cycle have also been reported. The latter cases have been associated with a variety of conditions and disorders: urea cycle disorders (4); propionic acidemia (5); hawkinsinuria (6); Stevens–Johnson syndrome and severe burns (7); homocystinuria (8); prematurity (9); glycine deficiency (10); patients on artificial diets (11); and drug treatment with acetaminophen (paracetamol) (12) and vigabatrin (13).
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