Too much iron in the body is usually due to hemochromatosis.
The diagnosis of "too much iron" is not always straightforward.
The main diagnostic test is a raised serum ferritin.
The degree of elevation of ferritin usually reflects the amount of iron in the body however there are other causes of a raised serum ferritin (see below).
Hemochromatosis is an inherited disorder that causes the body to absorb and store too much iron.
The extra iron builds up in organs and damages them.
Without treatment, the disease can cause these organs to fail.
Hemochromatosis is mainly associated with a defect in a gene called HFE. This gene helps regulate the amount of iron absorbed from food.
There are two known important mutations in HFE, named C282Y and H63D.
C282Y is the most important. When C282Y is inherited from both parents, too much iron is absorbed from the diet. H63D usually causes little increase in iron absorption, but a person with H63D from one parent and C282Y from the other may rarely develop hemochromatosis.
The genetic defect of hemochromatosis is present at birth, but symptoms rarely appear before adulthood. A person who inherits the defective gene from both parents may develop hemochromatosis.
A person who inherits the defective gene from only one parent is a carrier for the disease. There may be a slight increase in iron absorption but not enough to cause problems.
Hereditary hemochromatosis is one of the most common genetic disorders. It most often affects Caucasians of Northern European descent, although other ethnic groups are also affected.
About 1:200 people have two copies of the abnormal hemochromatosis gene and are susceptible to developing the disease. One person in 1:12 is a carrier.
Men are about much more likely to be diagnosed with the effects of hereditary hemochromatosis than women. Men tend to develop problems at a younger age. Females have the protective effect of menstruation.
Screening of relatives
Brothers and sisters of people who have hemochromatosis should have the genetic test to see if they have the disease (25% risk) or if they are carriers (50% risk).
Parents, children, and other close relatives of people who have the disease should have a serum ferritin and then the genetic test if this is abnormal.
An alternative to checking children is to have the partner tested.
If the partner is normal (no mutations) then the children can only be carriers (risk of 50%).
Checking children by a serum ferritin will not be useful before the age of 30 years as there has not been enough time to develop an abnormal degree of iron overload.
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