Our bodies need iron: to form the oxygen-carrying hemoglobin for our red blood cells, maintain our immune systems and keep our muscles and brains functioning properly. But not too much. Excess iron can build up in tissues like the liver, heart and pancreas, causing damage and possibly organ failure. Other than blood loss, there’s no way for the human body to rid itself of excess iron. The only way to regulate iron levels is by adjusting how much is taken in from food. Low iron levels in the body lead to more absorption in the gut, high iron leads to less. There are several known genetic mutations that interrupt this iron absorption control mechanism, leading to a condition called hereditary hemochromatosis. But there are some forms of this disease for which the causative mutation isn’t known, and not everyone with one of the known mutations actually ends up having hemochromatosis. These observations suggest there are genetic factors affecting iron level control that have yet to be identified. Two reports published online yesterday by the journal Nature Genetics
may have identified one of these additional genetic factors. Researchers working with mice have found that disrupting the function of the BMP6 gene can lead to iron overload much like that seen in the severe childhood-onset forms of human hemochromatosis.
“Although no human patients with BMP6 mutations have yet been described, our data …suggests that BMP6 mutations or BMP6 gene variants may function as another cause of hereditary hemochromatosis or a modifier of disease penetrance,” write the authors of one of the studies
. 23andMe customers can learn whether they are carriers of the mutations that cause adult-onset hemochromatosis using the Health and Traits feature.