 | |
Genetic tests can confirm a diagnosis and can help identify family members who are at risk for hemochromatosis.
Type I hemochromatosis, which occurs in adults, is caused by defects in the HFE gene. HFE has many purposes, but one important role is that it helps to control the amount of iron that is absorbed from food. There are several known defects in the HFE gene, but two defects are most often found in people with hemochromatosis. These two defects are called C282Y and H63D.
Everyone has two copies of HFE, one from Mom and one from Dad. A person can have two normal copies, one normal and one changed (mutated or mutation) copy; two copies of the same mutation; or two different mutated copies.
When a person has one mutated copy, he or she is called a carrier or heterozygote. When a person has two of the same mutated copies, he or she is called a homozygote. When a person has two different, but
|
|
mutated, copies, he or she is called a compound heterozygote. Genetics can be very difficult to
understand at first. What is most important is that you know which gene combination causes the greatest known risk of loading iron.
|
C282Y homozygote and the C282Y/H63D compound heterozygote
H63D homozygote
C282Y heterozygote (carrier) or H63D heterozygote (carrier)
| |
|
Several other genes and proteins that work with HFE have been discovered. These are called modifiers. Scientists are studying HFE and its modifiers to learn why some people get sick and others do not. The way these modifiers occur in a person with mutated copies of HFE may explain this difference.
|
