The MTHFR gene is one of the genes involved in the folate cycle. MTHFR is an enzyme that converts dietary folate or folic acid to the active form so it can be used by your body. Folate, or Vitamin B9, is essential for several important bodily functions from DNA repair and methylation; to keeping our nervous systems healthy. Folate deficiency can lead to increased homocysteine levels in the blood which can be an indicator of certain health issues. This variation of the gene influences how efficiently folate is processed through alterations in the enzyme activity.
Source: 1000 Genome Project. Global averages for both sexes