The TCN2 gene encodes transcobalamin II, a protein responsible for transporting vitamin B12 (cobalamin) from the bloodstream into cells. Once vitamin B12 is absorbed in the gut, it must bind to transcobalamin to be delivered to tissues where it is used for DNA synthesis, red blood cell production, and neurological function. Genetic variations in TCN2 can decrease the efficiency of B12 transport, potentially leading to functional B12 deficiency even when blood levels appear normal. This may contribute to symptoms such as fatigue, cognitive changes, or elevated homocysteine.
It encodes the protein transcobalamin II, which binds and transports vitamin B12 into cells for biological use.
Variants in this gene may decrease cellular uptake of B12, potentially impacting energy metabolism, nerve function, and methylation.
Yes, certain polymorphisms can hinder transport into cells, causing a functional deficiency even when serum B12 levels appear adequate.
Possible symptoms include fatigue, difficulty concentrating, numbness or tingling, and elevated homocysteine levels.