MTHFR mutation analysis - C677T
Definition
The MTHFR gene encodes methylenetetrahydrofolate reductase, an enzyme involved in folate metabolism that provides the folate form used in the conversion of homocysteine to methionine (see the Homocysteine entry). C677T and A1298C are common polymorphisms in the population, not pathogenic mutations; according to MedlinePlus, most people carrying this polymorphism do not develop neural tube defects. The American College of Medical Genetics and Genomics (ACMG) has stated that current meta-analyses do not confirm an association between the MTHFR polymorphism and elevated homocysteine, heart disease, and venous thromboembolism risk, and reassessed this document in 2020, reclassifying it from an evidence-based guideline to a Clinical Practice Resource. For this reason, it should be clearly stated that the test's prominence in popular health culture does not reflect the current level of evidence.
Gene/region examined
MTHFR - C677T
Method
Sequence analysis
Accepted sample types
EDTA blood
Inheritance
These variants are not disease-causing pathogenic mutations but common polymorphisms in the population; they should not be evaluated as a "disease" within the classic autosomal inheritance framework.