Causes

Haemochromatosis is caused by a genetic fault that can be passed on to a child by his or her parents.

Most cases are linked to a fault in a gene called HFE, which affects your ability to absorb iron from food.

Normally,your body maintains a steady level of iron. The amount of iron absorbed from food varies according toyour body's need for it.

But people with haemochromatosis can't control theiriron level.The level graduallyincreases over time and iron starts tobuild up in their organs, damaging them in the process.

How haemochromatosis is inherited

Everyone receives two sets of genes one from their father and one from their mother. You're only at risk of haemochromatosis if you inherit the faulty HFE gene from both of your parents.

If you only inherit the faulty gene from one parent, you'll be at risk of passing it on to your children known as being a "carrier"but you won't develop haemochromatosis yourself.

In certain ethnic groups, such as peoplewith a Celtic background which is common in Ireland, Scotland and Walesit's quite common to be a carrier of the faulty HFE gene.

If two carriers have a baby, there's a:

• 1 in 4 (25%) chance the baby will receive two normal versions of the HFE gene, so they won't have haemochromatosis and won't be a carrier
• 1 in 2 (50%) chance the baby will inherit one normal HFE gene and one faulty one, so they'll be a carrier but won't develop haemochromatosis
• 1 in 4 (25%) chance the baby will inherit two copies of the faulty HFE gene and will be at risk of developing haemochromatosis

But inheriting two copies of the genetic fault doesn't mean you'll definitely gethaemochromatosis.

Forunknown reasons, only a small proportion of people with two copies of the faulty HFE gene will ever develop the condition.