How do you diagnose an MTHFR gene mutation

Methylene tetrahydrofolate reductase (MTHFR) deficiency

A lack of enzymes reduces the availability of 5-methyl-THF for the remethylation of homocysteine ​​to the essential amino acid methionine. The residual activity of the MTHFR is usually <10%. The consequences are homocystinuria, hyperhomocysteinemia (homocysteine ​​level> 100 µmol / l) and reduced methionine plasma concentrations. The cause are pathogenic variants of the MTHFRGene located on the long arm of chromosome 1.

One occurs much more frequently mild shape MTHFR deficiency, which is caused by a thermolabile variant of the enzyme with impaired function. This mild form is characterized by increased homocysteine ​​levels (Hyperhomocysteinemia), in contrast to the classic form, however, there are no neurological symptoms. Molecular genetic can mostly be the common one C677T-variant (rs1801133) in exon 5 des MTHFR-Gens can be detected. Homozygosity for this variant is associated with an increased homocysteine ​​level. A weak positive association with multifactorial diseases such as thrombophilia or neural tube defects (spina bifida) is also only for homozygous carriers and just in combinationWith further Risk factors described. An adequate supply of folic acid, vitamins B6 and B12 is recommended for carriers of the T / T genotype. Another variant in MTHFR-Gene, A1298C (rs1801131), combined heterozygosity with the C677T variant is also associated with decreased enzyme activity and increased homocysteine ​​concentrations in the blood. However, homozygosity for the C / C genotype has no effect on folate-dependent homocysteine ​​metabolism.

The determination of the MTHFRGenotype is currently only used for patients with a Plasma homocysteine ​​concentration (tHyc) of >50µmol / L recommended. In connection with thrombophilia, the examination is currently not part of the statutory health care.