Final answer:
The HFE gene regulates hepcidin by producing a protein that senses body iron levels and modulates hepcidin expression accordingly, which is crucial for maintaining iron homeostasis.
Step-by-step explanation:
The gene that regulates hepcidin is the HFE gene, which produces a protein that interacts with transferrin receptors to sense body iron levels. Hepcidin itself is a key regulator of iron homeostasis in the body. When body iron levels are high, hepcidin expression is increased, and it acts to decrease iron absorption by binding to the iron exporter ferroportin which is present on the surface of enterocytes and macrophages, causing its internalization and degradation. This process prevents the release of iron to the circulation. In cases where the HFE gene's protein product is deficient or faulty, as in hereditary hemochromatosis, hepcidin regulation is impaired, leading to excessive iron accumulation. Thus, understanding the function of HFE and its relationship with hepcidin is crucial for maintaining proper iron balance and preventing related disorders.