Attention! Changes due to the COVID-19 pandemic!

The laboratory accepts clients and patients in person strictly by prior appointment. To apply for a visit, write to or call us 26267833! We recommend that you perform the DNA test remotely. More information here.

What is homocysteine?

MTHFR DNA test for a congenital tendency to increased blood levels of homocysteine

What is homocysteine?

Homocysteine is an amino acid circulating in the blood, which in the presence of vitamin B9 (folic acid), the body transforms into another amino acid — cysteine or methionine.

Elevated homocysteine levels increase oxidative stress. Pregnant women with elevated homocysteine levels are more prone to complications: recurrent early miscarriages, pre-eclampsia, placental abruption, foetal neural tube defects.

What is the role of the MTHFR gene in regulating homocysteine levels?

The product of the MTHFR gene affects the transformation of homocysteine to methionine. Decreased gene activity may increase homocysteine levels in the blood.

SIA GenEra offers testing of the two most common polymorphisms, the presence of which significantly reduces the activity of the MTHFR gene product, and thus increases the level of homocysteine and lowers the concentration of folates in the blood.

Use of medications and MTHFR

Several studies have shown that MTHFR polymorphism is associated with the toxicity of some drugs. For example, patients with genomic polymorphisms affecting MTHFR activity are more likely to experience drug intolerance. However, unfortunately, no guidelines have been developed for methotrexate dose adjustment to MTHFR genetic variations.

Who should undergo the MTHFR DNA test?

MTHFR DNA test is recommended in patients with elevated homocysteine levels in the blood, especially if there have been complications during pregnancy, or a family or personal history of cardiovascular disease or thrombosis.

MTHFR testing could also be indicated when prescribing drugs that affect folate metabolism (methotrexate) to patients with elevated blood levels of homocysteine to adjust the dose and reduce the risk of toxicity.


For patients with polymorphisms in the MTHFR gene, the risk of developing venous thrombosis is very low if homocysteine levels in the blood are normal. Pregnant women who are homozygous for c.677 have a small risk of foetal neural tube defects (spina bifida).

However, if the level of homocysteine in the blood is elevated, then homozygotes with the most frequent mutations pose a medium risk of venous thrombosis or pregnancy complications.


Individuals with c.677 TT genotype can take additional vitamin B9 (folic acid) to supplement their daily diet. Such dietary adjustment could compensate for the effect of reduced MTHFR activity on blood homocysteine levels.

However, your doctor will give you more specific advice. 


With a doctor’s referral (for a complete list, see the “Prices”) section) medical DNA tests (except for the prenatal NIPT “Panorama” test for pregnant women) are paid for by the NHS. Important! The NHS only pays for the test if the referral is issued as part of an NHS-paid visit, and the doctor has a contract with the NHS. Referrals issued during a paid visit will not be valid. Quotas are available.


The sample for DNA testing can be submitted at any branch of our partner - Centrālajā laboratorijā.


You can also order all offered DNA tests at full price. Remote contactless testing is available for both paid and NHS-referred tests. All medical DNA tests can be performed remotely, except for tests on pregnant women, where a blood sample must be collected. 

I have a referral and I want to collect and submit sample remotely

Do you have questions about testing opportunities?

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