A question from a colleague: My relative is 35 and is currently about 20 weeks pregnant. She has 2 healthy children, but has also had two miscarriages in the past three years. She is a double heterozygote for MTHFR C677T and A1298C. If I am interpreting the literature correctly, the double heterozygosity should not increase her chances for fetal loss. Is that correct?
Hello, and yes, that is correct. While several publications link methylene tetrahydrofolate reductase (MTHFR) gene double heterozygosity with chronic homocysteinemia, no investigation has found a link to increased risk of thrombosis. On the other hand, if her OB physician is convinced her previous losses were caused by thrombotic events, it may make sense for her to treat your relative with enoxaparin or fondaparinux, both of which are relatively safe when managed correctly. Geo.