Homozygous c.677C>T+c.677C>T in the Methylene tetrahydrofolate reductase (MTHFR) gene is associated with higher than normal levels of homocysteine, which may increase risk for thrombosis. In addition, this mutation/polymorphism is considered a MTHFR Thermolabile Variant and is associated with hyperhomocysteinemia, increased cardiovascular risk, increased risk of neural tube defects in offspring, and increased risk of preeclampsia. Furthermore, mutations in the MTHFR gene may cause MTHFR Deficiency/Homocystinuria. Please note, current knowledge indicates that heterozygous c.677C>T, a highly prevalent polymorphism, is not associated with increased thrombosis risk.
This laboratory performs targeted mutation analysis for c.677C>T and will only report it in the homozygous state.