Methylenetetrahydrofolate Reductase (MTHFR) Genotyping
Whole blood or buccal swabs
5 mL of whole blood or four buccal swabs
3 mL of whole blood or four buccal swabs
Lavender-stopper (EDTA) tube or paper envelope for dried buccal swabs
Maintain at room temperature or refrigerate
Cause for Rejection
Hemolyzed specimen; quantity not sufficient
General Purpose and Use
The MTHFR (Methylenetetrahydrofolate Reductase) enzyme catalyzes the formation of 5-methyltetrahydrofolate, the major circulating form of active folate. Absence of active folate leads to accumulation of plasma homocysteine. The 677 C>T polymorphism of MTHFR leads to decreased MTHFR enzymatic activity and elevated homocysteine. The 1298 A>C polymorphism is associated with significant increases plasma homocysteine levels only when in combination with the 677 C>T polymorphism. Elevated plasma homocysteine has been shown to be a risk factor for atherosclerotic heart disease, myocardial infarction, cerebrovascular disease, and venous thrombosis. Additionally, associations between the 677 C>T polymorphism and increased risk for methotrexate toxicity, increased chemosensitivity of colon and breast cancers to 5-fluorouracil, and increased risk of fetal neural tube defects in pregnant women have also been reported, although these associations remain controversial.
Other genetic variants of the MTHFR gene that are not detected in the assay may influence MTHFR enzymatic activity. Other genetic and non-genetic factors may also influence plasma folate and homocysteine levels, and the balance of proper coagulation.
Real-time polymerase chain reaction with fluorescence detection.
For a PDF version, click here.