Hemochromatosis is a hereditary disease characterized by improper processing by the body of dietary iron.
That causes the body to absorb and store too much iron, eventually causing organ dysfunction if no treatment is received.
Hemochromatosis is the foremost iron overload disorder. It is also spelled haemochromatosis.
Caucasians of northern European descent are at the highest risk of haemochromatosis.
Iron is an essential nutrient found in many foods. The greatest amount is found in red meat and iron fortified bread and cereal.
In the body, iron becomes part of hemoglobin. Hemoglobin is 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 to meet the body needs. When the body has enough iron, our cells stop absorbing it from food. If there is too little, they absorb more.
People with haemochromatosis absorb more than the body needs. The body has no natural way to rid itself of the excess iron. It is therefore stored in joints and major organs such as the liver, heart, brain, pancreas, and lungs.
Over many years, iron accumulates to toxic levels that can damage or even destroy an organ.
Causes of Hemochromatosis
Genetic haemochromatosis 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, namely C282Y and H63D. C282Y is the most important.
When C282Y is inherited from both parents, iron is over absorbed from the diet and haemochromatosis can result.
H63D usually causes little increase in iron absorption, but a person with H63D from one parent and C282Y from the other rarely develops hemochromatosis.
The genetic defect of hemochromatosis may be present at birth. However, 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 and normally does not develop it. However, carriers might have a slight increase in iron absorption.
Juvenile hemochromatosis and neonatal hemochromatosis are two forms of the disease that are not caused by an HFE defect. Their cause is unknown.
The juvenile form 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 the same problems in newborn infants.
Although both men and women can inherit the gene defect, men are about five times more likely to be diagnosed with the effects of hereditary hemochromatosis than women. Men also tend to develop problems from the excess iron at a younger age.
Haemochromatosis is said to be protean. This means it presents with symptoms that are often initially attributed to other diseases.
Children who test positive rarely have any symptoms because iron takes many years to accumulate.
Hemochromatosis symptoms include:
Males are usually diagnosed in their forties and women in their fifties. Delayed diagnosis for women is due to regular iron loss by menstruation which ceases in menopause.
Many people have no symptoms when they are diagnosed.
If the disease is not detected early and treated, iron may accumulate in body tissues and may eventually lead to serious problems. These include;
The damage from hereditary haemochromatosis is preventable if the condition is diagnosed and treated early.
One of the first steps in diagnosis is the measurement of ferritin. This is the tissue form of accumulated iron which is shed into the blood.
Other markers of iron metabolism are the iron carrying protein transferrin (decreased), transferrin saturation (increased) and serum iron (increased).
Genetic testing is performed if the biochemical markers are unstable.
Other blood tests routinely performed include blood count, renal function, liver enzymes, electrolytes, glucose (and/or an oral glucose tolerance test (OGTT).
A thorough medical history, a physical examination, and routine blood tests help rule out other conditions that could be causing the symptoms.
The information may provide helpful clues, such as a family history of arthritis or unexplained liver disease.
Blood tests determine whether the amount of iron stored in the body is too high. The transferrin saturation test determines how much iron is bound to the protein that carries iron in the blood.
The total iron binding capacity (TIBC) test measures how well your blood can transport iron. 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 help 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, in which a tiny piece of liver tissue is removed and examined under a microscope, may be needed. It will show how much iron has accumulated in the liver and whether the liver is damaged.
Hemochromatosis is often left undiagnosed and untreated. It is considered rare and doctors may not think of testing for it. The initial symptoms can be diverse and vague and can mimic the symptoms of many other diseases.
Also, doctors 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 (hepatologist), digestive disorders (gastroenterologist), or blood disorders (hematologist).
Because of the other problems associated with hemochromatosis, several other specialists may be on the treatment team, such as an endocrinologist, cardiologist, or rheumatologist. Internists or family practitioners can also treat the disease.
Specific treatment for complications of the condition such as insulin for diabetes is normally required. Otherwise the first step in treatment of hemochromatosis is to rid the body of excess iron. This process is called phlebotomy. Blood is removed the same way it is drawn from donors at blood banks.
Depending on how severe the iron overload is, a pint of blood will be taken once or twice a week for several months to a year. Occasionally it is taken for a longer period until the level of iron in the body has dropped to normal.
The patient then remains in a maintenance schedule where blood ferritin levels will then 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 litre of serum.
Depending on the amount of iron overload at diagnosis, reaching normal levels can take many phlebotomies.
Once iron levels return to normal, maintenance therapy, which involves giving a pint of blood every 2 to 4 months for life, begins. Some people may need it more often. An annual blood ferritin test will help determine how often blood should be removed.
The earlier hemochromatosis is diagnosed and treated in appropriate cases, the better.
If treatment begins before any organs are damaged, associated conditions such as liver disease, heart disease, arthritis, and diabetes can be prevented.
The position of people who already have these conditions at diagnosis depends on the degree of organ damage. Treating hemochromatosis may for example stop the progression of liver disease in its early stages. This means a normal life expectancy.
If liver cirrhosis has developed, the person's risk of developing liver cancer increases, even if iron stores are reduced to normal levels. There is therefore the need for appropriate regular follow-up with a specialist.
People who have complications of hemochromatosis may want to consider getting treatment from a specialized hemochromatosis center.
People with hemochromatosis should not take iron supplements. Those who have liver damage should not drink alcoholic beverages because they may further damage the liver.
Although treatment cannot cure the conditions associated with established hemochromatosis, it will help most of them. The main exception is arthritis, which does not improve even after excess iron is removed.
Tests for Hemochromatosis
Testing people who have no symptoms of hemochromatosis is not a routine part of medical care and checkups. Researchers however suggest that:
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 to show that it is the consequence of iron overload.