Can TMPRSS6 rs855791 CT and TF rs3811647 AG shift iron-related lab patterns?

At age 53, these variants may modestly influence iron-related laboratory patterns, but neither genotype alone establishes iron deficiency or a need for treatment.

Clinical and biomarker evidence

• TMPRSS6 rs855791 CT: A contribution to reduced iron availability is biologically plausible, but direct evidence for a CT-specific hepcidin or iron phenotype is indirect. Human comparisons of homozygotes found TT versus CC associated with lower serum iron, transferrin saturation, and fractional iron absorption in non-anemic Taiwanese women; a meta-analysis found no significant association with diagnosed anemia. Sex, menstrual blood loss, diet, inflammation, and baseline iron stores can substantially modify measured iron indices.
• TF rs3811647 AG: The A allele has a robust additive association with higher transferrin and TIBC. One GWAS estimated approximately 0.40 phenotypic SD higher transferrin per A allele (P = 3.0 × 10⁻¹⁵); TIBC associations were also highly significant (P = 7.0 × 10⁻⁹; combined P = 4.5 × 10⁻¹⁰). AA versus GG differences were about 21% for transferrin and 16% for TIBC, making a smaller intermediate increase expected with AG.

Mechanistic interpretation

• TMPRSS6 encodes hepatic matriptase-2, which normally restrains the BMP–SMAD/hemojuvelin pathway and suppresses HAMP (hepcidin) transcription. Reduced TMPRSS6 activity can increase hepcidin, restricting intestinal iron absorption and circulating iron availability.
• Higher transferrin/TIBC from rs3811647 AG reflects greater iron-binding capacity, not necessarily lower serum iron or depleted stores. This variant was not associated with serum iron in one GWAS.

Clinical implications

• Bottom line: The combined genetic pattern can be compatible with lower iron availability plus higher transferrin/TIBC, but it cannot diagnose iron deficiency. Interpretation should rest on ferritin, transferrin saturation, serum iron, and inflammatory context rather than TIBC or genotype alone.