Medicine
Genetic Basis of Hereditary Hemochromatosis
Quick fact
About 1 in 200 people of Northern European descent carry two copies of the HFE C282Y mutation, making hereditary hemochromatosis the most common genetic disorder in that population.
Why this is interesting
Imagine your body absorbing too much iron from every meal—iron that slowly accumulates in your organs, eventually damaging them. Why would your body do that? The answer lies in a small change in your DNA.
Read the full explanation
Understanding Genetic Basis of Hereditary Hemochromatosis
Hereditary hemochromatosis is a condition where the body absorbs too much iron from the diet. Normally, when iron levels are sufficient, the body reduces absorption. In hemochromatosis, this regulation fails, and iron builds up in organs like the liver, heart, and pancreas. The most common cause is a mutation in the HFE gene, which normally helps the body sense iron levels. Think of it as a broken thermostat: the body doesn't know it has enough iron, so it keeps absorbing more.
A deeper explanation
The HFE gene encodes a protein that interacts with the transferrin receptor, helping to sense iron levels. In hereditary hemochromatosis, mutations like C282Y disrupt this protein, impairing the signaling that normally stimulates production of hepcidin, the master iron-regulatory hormone. With less hepcidin, the iron transporter ferroportin is not degraded, so enterocytes release more iron into the blood. Over years, the excess iron deposits in tissues, causing oxidative stress and organ damage. The inheritance is autosomal recessive: a person must inherit two mutated copies (one from each parent) to develop the disease, while carriers have mild or no symptoms.