New Clues to Cause of Iron Disorder
Dysfunction of one protein may lead to hemochromatosis, researchers find
WEDNESDAY, March 16, 2005 (HealthDay News) -- Researchers say they have identified a protein they believe is key to the iron disorder hemochromatosis.
The finding could lead to new treatments for this relatively common disease, in which tissues become overloaded with iron. About one in every 200 to 300 Americans are affected by hemochromatosis, which can lead to organ failure if left untreated.
Reporting in the March issue of Cell Metabolism, researchers at Children's Hospital Boston and Harvard Medical School study found the protein ferroportin is the major, and possibly only, iron exporter functioning at key points of iron absorption and release in the body. This suggests that iron accumulation in people with hemochromatosis may be the result of ferroportin-related loss of control over iron export.
"Iron is essential in the body and abundant in the environment, but it's also very reactive and damaging when in excess. Mammals have therefore evolved mechanisms to get enough iron from the diet, but not too much," senior author Nancy Andrews said in a prepared statement.
She and her colleagues disabled ferroportin in select tissues and then systemwide in developing mice.
Mice that completely lacked ferroportin died early in development, due to a failure of iron transfer from mother to embryo. Mice lacking ferroportin in all tissues except those critical for nutrient transfer from the mother survived, but quickly become anemic after birth due to a lack of iron in the blood.
When the researchers examined the intestines, livers and spleens of these mice, they found an accumulation of iron within cells. This indicates that the cells aren't able to release iron once it's absorbed.
Mice that lacked ferroportin in their intestinal cells developed severe iron deficiency anemia. This further confirmed the role of ferroportin in iron absorption, the authors said.
The U.S. National Digestive Diseases Information Clearinghouse has more about hemochromatosis.