The TCN2 gene encodes for the activity involved in binding vitamin B12 and transporting it from the intestine into the blood cells. Variants are linked to low plasma vitamin B12 levels. Low vitamin B12 is associated with high homocysteine, which can be neurotoxic and a risk factor for cardiovascular disease, anaemia, low energy, pale skin, headaches, feeling faint and heart palpitations.
If you have the GG allele in this gene, you are likely to have a severely reduced ability to transport vitamin B12 into your blood cells. If you experience any of the symptoms listed or suspect low vitamin B12 levels (e.g. if you follow a vegetarian or vegan diet or consume a large amount of alcohol), have your vitamin B12 levels tested, increase your intake of vitamin B12 foods and/or supplements and minimise alcohol intake. Vitamin B12 is also important for healthy methylation.