What is Haemochromatosis?
Haemochromatosis is a medical condition caused by an overload of iron in your body.
There are several forms of haemochromatosis. This leaflet provides information about the most common form, known as hereditary or genetic haemochromatosis (GH), and looks very briefly at some more rare forms and other types of iron-overloading disorders.
In genetic haemochromatosis, inheritance of a faulty or abnormal gene is responsible for an increase in the amount of iron entering the body.
Iron is a mineral that is essential to help your body grow. Some minerals, such as calcium, sodium and potassium, are required by your body in large amounts (‘macrominerals’). Iron is a ‘trace mineral’ which is needed in smaller amounts. Other trace minerals include zinc, copper and chromium. As a nutrient, iron is important in your diet to help make haemoglobin, a vital protein in red blood cells. Haemoglobin gives red blood cells their colour and helps them carry oxygen around your body.
If you receive too little iron, you can become anaemic. In fact, a lack of iron in the body is the most common nutritional deficiency in the UK and throughout the world.
Iron enters the body when nutrients are taken in, or absorbed, by your small intestine following digestion. An overload of iron is caused by an increase in the absorption of iron from food.
About two thirds of the iron absorbed is incorporated into haemoglobin itself. Most of the rest is stored in your liver, with smaller amounts distributed to other organs and body tissue. Normally you should have around three to four grams (g) of iron in your body.
Iron storage is thought to be an evolutionary survival mechanism. When the body loses a large amount of blood, it replaces the lost blood cells more quickly than it can take on enough dietary iron to make haemoglobin. Over time, the body developed the ability to absorb and store extra iron in case it was required. Today, blood transfusions and infusion of iron intravenously can provide iron rapidly in a medical emergency.
When red blood cells die, the iron in the haemoglobin is rapidly released to make new haemoglobin and any excess returns to storage. Only small amounts of iron – around a milligram (mg) – are lost from the body each day, mostly in cells from the gut. Your body has no natural mechanism for getting rid of unwanted iron once it has been absorbed.
People with haemochromatosis absorb at least twice as much iron as normal. When more than five grams of iron has been absorbed, it will start to become deposited around the body. An excessive amount of iron can mean 20g or more.
The poisonous (toxic) effects of this extra iron mean that haemochromatosis is a potentially lethal condition, but it can be treated effectively if diagnosed early enough.