rs3811647

rs3811647 is a common intron 11 variant in TF, the gene encoding transferrin, the plasma protein that transports iron. It is a non-coding variant that alters an enhancer element (the A allele shows higher enhancer activity in liver-cell assays than the G allele) and modulates TF gene expression, with AA carriers showing roughly 21% higher transferrin, 24% higher unsaturated iron-binding capacity, and 25% lower transferrin saturation than GG carriers. Along with TMPRSS6 rs855791, it is used to assess genetic tendency toward lower, typical, or higher circulating iron status, distinct from hemochromatosis.