Chapter 1: Ironing It Out

This chapter primarily focuses on hemochromatosis, a hereditary disease that results in the disruption of the negative feedback loop used to tell the body to stop absorbing iron. This results in an extreme excess of iron within the body. The increased iron levels cause pain and damage to joints, internal organs, and chemical properties of the body. If left alone, hemochromatosis can ultimately lead to death. The only way to treat this disease is to literally drain blood from the body to decrease iron levels. The gene that causes hemochromatosis is most common in people of Western European descent. Why has this gene not been selected against throughout the years? Dr. Sharon Moalem makes a strong argument towards the notion that this gene is responsible for an increased immunity to the bubonic plague, which predominantly affected Western Europe in the fourteenth century. Dr. Moalem indicates that all life forms need iron to live and proliferate and that many illnesses are able to overtake the immune system by absorbing the iron present in the macrophages sent to kill them. What makes people with hemochromatosis unique, is that interestingly, their macrophages have been found to lack the presence of iron, making them ideal for combating illness. So, it is believed that hemochromatosis originally came about via a genetic mutation that occurred before the bubonic plague and then was selected for during the bubonic plague, leading to the prevalence of the gene that causes hemochromatosis in the population today.