Disorders of folate metabolism

Vitamin B9 (folic acid)

 * Folate (pteroylglutamic acid) is found in leafy vegetables, legumes, liver
 * Pteroylglutamic acid consists of pteridine, p-aminobenzoic acid and glutamic acid
 * Reduction to dihydrofolate (DHF) and tetrahydrofolate (THF) occurs in folate metabolism
 * It serves as a transporter of single-carbon residues, which is essential for the endogenous formation of methionine, thymidylate (dTMP) and two intermediates in purine synthesis.

Hereditary folate malabsorption

 * Severe megaloblastic anemia, progressive neurological disorders
 * Folate deficiency syndrome in the brain with reduced levels of folate transporter in the brain
 * Treatment with high doses of folate orally or lower parenterally

Glutamate formimino transferase deficiency

 * Histidine catabolism is associated with the transfer of the formimino group to THF with the concomitant release of ammonia
 * It has two catalytic activities as glutamate formiminotransferase and as formiminotetrahydrofolate cyclodeaminase
 * Psychomotor retardation, megaloblastic anemia
 * Hyperhistinemia and histidinuria develop

Methylenetetrahydrofolate reductase deficiency (MTHFR)

 * Methyl-THF is a methyl donor for the conversion of homocysteine to methionine and the MTHFR deficiency results in an increase in total plasma homocysteine concentration and a decrease in methionine concentration leading to developmental delay, microcephaly, convulsions, hyperhomocysteinemia

Links

 * Vitamin B9
 * Disorders of cobalamin metabolism
 * Disorders of sulfur amino acid metabolism

Source

 * FERNANDES, John. Diagnostika a léčba dědičných metabolických poruch. 1. vydání. Praha : Triton, 2008. s. 576-580.  ISBN 978-80-7387-096-6.


 * MURRAY, Robert K., Daryl K. GRANNER a Peter A. MAYES, et al. Harperova biochemie. 4. vydání. Jinočany : H & H, 2002. 872 s.  ISBN 80-7319-013-3.