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 formation, and neurological function. Genetic variations in TCN2 can reduce 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 to and transports vitamin B12 into cells for biological use.
Variants in this gene may reduce cellular uptake of vitamin B12, potentially affecting energy metabolism, nerve function, and methylation.
Yes, certain polymorphisms can hinder cellular transport, resulting in functional deficiency despite adequate serum B12 levels.
Possible symptoms include fatigue, poor concentration, numbness or tingling, and raised homocysteine levels.