MTHFR gene mutation and folic acid absorption
Package MTHFR – folic acid absorption – price 135 BGN.
- MTFHR C677 (normal allele)
- MTFHR 677T (mutant allele)
- MTFHR A1289 (normal allele)
- MTFHR 1289C (mutant allele)
The methylenetetrahydrofolate reductase (MTHFR) gene controls the production of the MTHFR enzyme. This enzyme converts one form of folate to another and is part of the process by which homocysteine is converted to methionine, an important building block for many proteins.
The most common variants of the MTHFR gene are C677T and A1298C. The C677T variant results in a less active form of the MTHFR enzyme. In homozygous C677T carriers, 70% of cases have reduced enzyme activity and about twice the homocysteine levels. Heterozygous carriers of the C677T mutation alone do not have hyperhomocysteinemia and clinical manifestation.
The other common mutation in the MTHFR gene is A1298C. Hyperhomocysteinemia is not observed in heterozygous or homozygous carriers of the A1298C allele alone and, accordingly, there is no clinical manifestation. When a person has one copy of MTHFR C677T and one copy of A1298C (combined heterozygote), observed in 15-20% of cases, the reduced activity of the MTHFR enzyme slows down the process of conversion of homocysteine to methionine and may lead to accumulation of homocysteine in the blood.
Studies suggest that high levels of homocysteine in the blood may contribute to the risk of cardiovascular disease by damaging blood vessel walls and promoting plaque formation (atherosclerosis) and thrombosis. This is of particular concern in pregnant women who have this mutation, because fetal neural tube defects, stillbirths and recurrent miscarriages are very common in fetuses with folate deficiency.
The increase in homocysteine is often mild to moderate, but varies from person to person depending on the amount of activity of the MTHFR enzyme. The elevation of homocysteine in the blood is worsened when the affected person has a folic acid deficiency. Conditions associated with the presence of mutations in the gene for MTHFR are: homocystinuria – abnormally high levels of homocysteine in the blood or urine; anaemia; ataxia; microcephaly; peripheral neuropathy; depression.
