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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.
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] Elevations of homocysteine can also occur in the rare hereditary disease homocystinuria. [citation needed]
There is an association between the blood levels of homocysteine and thrombosis, [16] although this has not been reported consistently in all studies. [5] Homocysteine levels are determined by mutations in the MTHFR and CBS genes, but also by levels of folic acid, vitamin B 6 and vitamin B 12, which depend on diet. [14]
Homocysteine is elevated (5-MTHF is used to convert homocysteine to methionine) as in vitamin B 12 deficiency, whereas methylmalonic acid is normal (elevated in vitamin B 12 deficiency). [citation needed] More specifically, according to a 2014 UK guideline, [30] A serum folate level of less than 7 nmol/L (3 μg/L) is indicative of folate ...
In the body, homocysteine can be recycled into methionine or converted into cysteine with the aid of vitamin B 6, B 9, and B 12. [3] High levels of homocysteine in the blood (hyperhomocysteinemia) is regarded as a marker of cardiovascular disease, likely working through atherogenesis, which can result in ischemic injury.
Smartwatches are a hot-ticket gift over the holidays, but a new study might have you rethink how you strap the device to your wrist in the future.
C677T or rs1801133 is a genetic variation—a single nucleotide polymorphism (SNP)—in the MTHFR gene. Among Americans the frequency of T-homozygosity ranges from 1% or less among people of sub-Saharan African descent to 20% or more among Italians and Hispanics. [1] It has been related to schizophrenia [2] Alzheimer's disease [3] depression [4 ...