Search results
Results From The WOW.Com Content Network
Methylenetetrahydrofolate reductase deficiency is the most common genetic cause of elevated serum levels of homocysteine (hyperhomocysteinemia). It is caused by genetic defects in MTHFR, which is an important enzyme in the methyl cycle. [1] Common variants of MTHFR deficiency are asymptomatic and have only minor effects on disease risk. [2]
Methylenetetrahydrofolate reductase (MTHFR) is the rate-limiting enzyme in the methyl cycle, and it is encoded by the MTHFR gene. [5] Methylenetetrahydrofolate reductase catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate , a cosubstrate for homocysteine remethylation to methionine .
Genetic defects in 5-MTHF reductase can consequently lead to hyperhomocysteinemia. The most common polymorphisms are known as MTHFR C677T and MTR A2756G. [23] [24] The homozigote mutation G;G also called C;C (it is equivalent) occurs in about 10% of the population of european ethnicity (white caucasians). [25]
5,10-Methylenetetrahydrofolate (N5,N10-Methylenetetrahydrofolate; 5,10-CH 2-THF) is cofactor in several biochemical reactions. It exists in nature as the diastereoisomer [6R]-5,10-methylene-THF. As an intermediate in one-carbon metabolism, 5,10-CH 2 -THF converts to 5-methyltetrahydrofolate , 5-formyltetrahydrofolate , and methenyltetrahydrofolate.
5,10-Methenyltetrahydrofolate synthetase deficiency (MTHFS deficiency) is a rare neurodevelopmental disorder caused by mutations affecting the MTHFS gene, which encodes the enzyme 5,10-Methenyltetrahydrofolate synthetase. [2] The disease starts at birth or in early infancy and presents with microcephaly, short stature, and developmental delay.
Levomefolic acid is generated by methylenetetrahydrofolate reductase (MTHFR) from 5,10-methylenetetrahydrofolate (MTHF) and used to recycle homocysteine back to methionine by methionine synthase (MS). [2] L-Methylfolate is water-soluble and primarily excreted via the kidneys.
In humans, tetrahydrofolic acid is produced from dihydrofolic acid by dihydrofolate reductase. This reaction is inhibited by methotrexate. [1] It is converted into 5,10-methylenetetrahydrofolate by serine hydroxymethyltransferase. Many bacteria produce tetrahydrofolic acid via dihydropteroate.
Other causes appear to be Kearns–Sayre syndrome [5] and autoantibodies to the folate receptor. [6] [7] [8] For people with the FOLR1 mutation, even when the systemic deficiency is corrected by folate, the cerebral deficiency remains and must be treated with folinic acid. Success depends on early initiation of treatment and treatment for a ...