Iron Overload And Diabetes

Source: Diabetes Forecast
November 2003

Many people have never heard of hereditary hemochromatosis (HH), the most common genetic disease among white people–even though it sometimes causes diabetes.

What Is HH?

HH is an inherited disorder in which the intestines absorb more iron and other metals from the diet than the body needs. Excess iron is then deposited in the liver, pancreas, joints, heart, and other organs. As iron builds up over time, it can damage these organs. Too much iron deposited in the pancreas can lead to diabetes.

There are also non-genetic causes of iron overload. These include chronic liver disease, multiple blood transfusions, and long-term use of iron supplements.

What Causes HH?

The usual cause is a gene called HFE. When people inherit a defective copy from their mother and another defective copy from their father, they tend to absorb and store too much metal. Sometimes, other defective genes are at fault.

Who Gets HH?

The disease affects people whose ancestors came from northern Europe. One of every 250 white Americans has two defective copies of the HFE gene. Having two defective HFE genes, however, does not automatically lead to HH. Women get HH less often and later than men because they lose iron during their periods and, during pregnancy. Also, HH can be prevented when treatment starts before organ damage occurs.

What Are The Symptoms?

Symptoms generally start after age 40 and vary from person to person. Joint pain is the most common. Others include abdominal pain, fatigue, anemia, enlarged liver, heart muscle damage, an underactive thyroid gland, premature menopause, infertility, impotence, lack of periods, and, in advanced cases, darkened skin, diabetes, and cirrhosis (scarring) of the liver. Genetic testing lets many people find out they have two copies of the HFE gene before they ever have symptoms or serious damage.