The Medical Minute: Hemochromatosis, too much of a good thing

By John Messmer

Iron is one of the more abundant metals on the planet and is an essential nutrient. Its major role is in the hemoglobin of red blood cells where it serves to carry oxygen to the tissues. Babies and women in particular have a need for adequate iron intake, but some people have more iron than they need due to an inherited problem of iron metabolism -- hereditary hemochromatosis or HH.

HH is one of the most common genetic diseases in the U.S., occurring in one in 200 Caucasians with one in 10 being a carrier – most, but not all of these having Celtic ancestry (Irish, Scottish, Welsh or British). It is often called the “Celtic Curse.” By contrast, sickle cell anemia occurs in one in 500 African-Americans with one in 12 being carriers. Despite its prevalence, HH remains relatively unknown, even among physicians. Since the Celtic population stretched from what is now eastern Russia, north to Scandinavia and south to Spain, Greece and Turkey, it is by no means just a disease of those whose ancestors are from the British Isles.

HH causes iron to be absorbed even when it is not needed. Normally, we absorb a tiny amount of iron daily, just enough to replace what we lose from normal bodily functions and to sustain normal physiology. In hemochromatosis, iron continues to be absorbed excessively. Once our normal iron storage sites are full, iron will be stored in the liver, heart, skin and other organs, damaging them.

HH is the result of genetic mutations, the most common ones called C282Y and H63D. The mutation is believed to have developed about 40,000 years ago in what is now Ireland to compensate for an iron-poor diet. At that time, it would have been beneficial.

The mutations are passed on from parents to children. The HH genes are recessive; that means the disease occurs only when two copies of the gene are present -- one from each parent. If only one copy is passed, the person is a carrier. Carriers can store too much iron, but they rarely have organ damage.

In the most common form of HH, males usually do not develop symptoms until after age 30, but women may not show problems until after menopause because they lose iron regularly during menses. Symptoms relate to the organs that become overloaded with iron and can include arthritis, liver disease, diabetes, thyroid deficiency, bronze skin color, impotence, adrenal gland abnormalities and such nonspecific symptoms as fatigue or aches. Untreated, it can be fatal.

The problem is easy to diagnose before any damage occurs by measuring iron levels in the blood. This is a different test than a blood count, the typical test for anemia. Having a normal blood count does not give any information about HH. Blood donor centers test for too little iron; passing the test does not say anything about having too much iron.

Screening for HH is done with a serum iron level and transferrin saturation and often a ferritin level. Transferrin is a protein that carries iron in the blood and ferritin is an iron storage protein. If the iron level is high and transferrin is more than 40 percent saturated or ferritin is higher than 200 or so, HH should be considered. If your doctor tells you your iron is great or high enough that you don’t have to worry about anemia, ask how high it is and whether you should be tested for hemochromatosis.

To diagnose HH, a blood sample is checked for the two more common DNA mutations. Until the DNA test was available, liver biopsy was needed to test for iron deposits. Biopsy is reserved for those who develop cirrhosis of the liver to help determine if the cause is hemochromatosis.

People with one copy should avoid taking extra iron in vitamins and supplements and should avoid using iron cookware and extra vitamin C, which enhances iron absorption. A person with two copies of the gene has the disease and should begin a program of iron elimination through therapeutic phlebotomy. This is just like the process of donating blood -- a unit is removed as often as weekly to reduce iron levels to normal. Treatment can be ordered by many types of medical specialists including your family physician.

The family of anyone with even one HH gene should speak with their physicians about testing even if they have no symptoms. Those with the disease will pass on one copy of the gene to each of their children. Carriers have a 50:50 chance of passing on one hemochromatosis gene to each child. Some advocate testing in childhood if one or both parents are known to carry the gene so the child’s diet can be managed to keep iron levels under control.

HH is a fairly common disorder, but often it is not considered. Fortunately, it’s easy to find and treat, especially if detected early. If it’s in your family or you are of Celtic ancestry, ask your doctor if you should be screened.

To learn more about hemochromatosis, please visit the Penn State Milton S. Hershey Medical Center Health Information Library online.

John Messmer is associate professor of family and community medicine at Penn State College of Medicine and a staff physician at Penn State Hershey Medical Center.

Last Updated July 09, 2009