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What is hemochromatosis?
Hemochromatosis is the most common form of iron overload disease.
Primary hemochromatosis, also called hereditary hemochromatosis,
is an inherited disease. Secondary hemochromatosis is caused by
anemia, alcoholism, and other disorders.
Juvenile hemochromatosis and neonatal hemochromatosis are two
additional forms of the disease. Juvenile hemochromatosis leads to
severe iron overload and liver and heart disease in adolescents
and young adults between the ages of 15 and 30. The neonatal form
causes rapid iron buildup in a baby’s liver that can lead to
death.
Hemochromatosis causes the body to absorb and store too much iron.
The extra iron builds up in the body’s organs and damages them.
Without treatment, the disease can cause the liver, heart, and
pancreas to fail.
Iron is an essential nutrient found in many foods. The greatest
amount is found in red meat and iron-fortified breads and cereals.
In the body, iron becomes part of hemoglobin, a molecule in the
blood that transports oxygen from the lungs to all body tissues.
Healthy people usually absorb about 10 percent of the iron
contained in the food they eat, which meets normal dietary
requirements. People with hemochromatosis absorb up to 30 percent
of iron. Over time, they absorb and retain between five to 20
times more iron than the body needs.
Because the body has no natural way to rid itself of the excess
iron, it is stored in body tissues, specifically the liver, heart,
and pancreas.
What
causes hemochromatosis?
Hereditary hemochromatosis is mainly caused by a defect in a gene
called HFE, which helps regulate the amount of iron absorbed from
food. The two known mutations of HFE are C282Y and H63D. C282Y is
the most important. In people who inherit C282Y from both parents,
the body absorbs too much iron and hemochromatosis can result.
Those who inherit the defective gene from only one parent are
carriers for the disease but usually do not develop it; however,
they still may have higher than average iron absorption. Neither
juvenile hemochromatosis nor neonatal hemochromatosis are caused
by an HFE defect. Juvenile and neonatal hemochromatosis are caused
by a mutation in a gene called hemojuvelin.
What
are the risk factors of hemochromatosis?
Hereditary hemochromatosis is one of the most common genetic
disorders in the United States. It most often affects Caucasians
of Northern European descent, although other ethnic groups are
also affected. About five people out of 1,000—0.5 percent—of the
U.S. Caucasian population carry two copies of the hemochromatosis
gene and are susceptible to developing the disease. One out of
every 8 to 12 people is a carrier of one abnormal gene.
Hemochromatosis is less common in African Americans, Asian
Americans, Hispanics/Latinos, and American Indians.
Although both men and women can inherit the gene defect, men are
more likely than women to be diagnosed with hereditary
hemochromatosis at a younger age. On average, men develop symptoms
and are diagnosed between 30 to 50 years of age. For women, the
average age of diagnosis is about 50.
What
are the symptoms of hemochromatosis?
Joint pain is the most common complaint of people with
hemochromatosis. Other common symptoms include fatigue, lack of
energy, abdominal pain, loss of sex drive, and heart problems.
However, many people have no symptoms when they are diagnosed.
If the disease is not detected and treated early, iron may
accumulate in body tissues and eventually lead to serious problems
such as
- arthritis
- liver disease, including an enlarged liver,
cirrhosis, cancer, and liver failure
- damage to the pancreas, possibly causing
diabetes
- heart abnormalities, such as irregular heart
rhythms or congestive heart failure
- impotence
- early menopause
- abnormal pigmentation of the skin, making it
look gray or bronze
- thyroid deficiency
- damage to the adrenal glands
How is
hemochromatosis diagnosed?
A thorough medical history, physical examination, and routine
blood tests help rule out other conditions that could be causing
the symptoms. This information often provides helpful clues, such
as a family history of arthritis or unexplained liver disease.
- Blood tests can determine whether the amount
of iron stored in the body is too high. The transferrin
saturation test reveals how much iron is bound to the protein
that carries iron in the blood. Transferrin saturation values
higher than 45 percent are considered too high.
- The total iron binding capacity test measures
how well your blood can transport iron, and the serum ferritin
test shows the level of iron in the liver. If either of these
tests shows higher than normal levels of iron in the body,
doctors can order a special blood test to detect the HFE
mutation, which will confirm the diagnosis. If the mutation is
not present, hereditary hemochromatosis is not the reason for
the iron buildup and the doctor will look for other causes.
- A liver biopsy may be needed, in which case a
tiny piece of liver tissue is removed and examined with a
microscope. The biopsy will show how much iron has accumulated
in the liver and whether the liver is damaged.
Hemochromatosis is considered
rare and doctors may not think to test for it. Thus, the disease
is often not diagnosed or treated. The initial symptoms can be
diverse, vague, and mimic the symptoms of many other diseases. The
doctors also may focus on the conditions caused by
hemochromatosis—arthritis, liver disease, heart disease, or
diabetes—rather than on the underlying iron overload. However, if
the iron overload caused by hemochromatosis is diagnosed and
treated before organ damage has occurred, a person can live a
normal, healthy life.
Hemochromatosis is usually treated by a specialist in liver
disorders called a hepatologist, a specialist in digestive
disorders called a gastroenterologist, or a specialist in blood
disorders called a hematologist. Because of the other problems
associated with hemochromatosis, other specialists may be involved
in treatment, such as an endocrinologist, cardiologist, or
rheumatologist. Internists or family practitioners can also treat
the disease.
How is hemochromatosis
treated?
Treatment is simple, inexpensive, and safe. The first step is to
rid the body of excess iron. This process is called phlebotomy,
which means removing blood the same way it is drawn from donors at
blood banks. Based on the severity of the iron overload, a pint of
blood will be taken once or twice a week for several months to a
year, and occasionally longer. Blood ferritin levels will be
tested periodically to monitor iron levels. The goal is to bring
blood ferritin levels to the low end of normal and keep them
there. Depending on the lab, that means 25 to 50 micrograms of
ferritin per liter of serum.
Once iron levels return to normal, maintenance therapy begins,
which involves giving a pint of blood every 2 to 4 months for
life. Some people may need phlebotomies more often. An annual
blood ferritin test will help determine how often blood should be
removed. Regular follow-up with a specialist is also necessary.
If treatment begins before organs are damaged, associated
conditions—such as liver disease, heart disease, arthritis, and
diabetes—can be prevented. The outlook for people who already have
these conditions at diagnosis depends on the degree of organ
damage. For example, treating hemochromatosis can stop the
progression of liver disease in its early stages, which leads to a
normal life expectancy. However, if cirrhosis, or scarring of the
liver, has developed, the person’s risk of developing liver cancer
increases, even if iron stores are reduced to normal levels.
People with complications of hemochromatosis may want to receive
treatment from a specialized hemochromatosis center. These centers
are located throughout the country. Information is available from
the organizations listed under For More Information.
People with hemochromatosis should not take iron or vitamin C
supplements. And those who have liver damage should not consume
alcoholic beverages or raw seafood because they may further damage
the liver.
Treatment cannot cure the conditions associated with established
hemochromatosis, but it will help most of them improve. The main
exception is arthritis, which does not improve even after excess
iron is removed.
How is
hemochromatosis tested?
Screening for hemochromatosis—testing people who have no
symptoms—is not a routine part of medical care or checkups.
However, researchers and public health officials do have some
suggestions.
- Siblings of people who have hemochromatosis
should have their blood tested to see if they have the disease
or are carriers.
- Parents, children, and other close relatives
of people who have the disease should consider being tested.
- Doctors should consider testing people who
have joint disease, severe and continuing fatigue, heart
disease, elevated liver enzymes, impotence, and diabetes because
these conditions may result from hemochromatosis.
Since the genetic defect is
common and early detection and treatment are so effective, some
researchers and education and advocacy groups have suggested that
widespread screening for hemochromatosis would be cost-effective
and should be conducted. However, a simple, inexpensive, and
accurate test for routine screening does not yet exist and the
available options have limitations. For example, the genetic test
provides a definitive diagnosis, but it is expensive. The blood
test for transferrin saturation is widely available and relatively
inexpensive, but it may have to be done twice with careful
handling to confirm a diagnosis and show that the result is the
consequence of iron overload.
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