Too little iron in the blood can lead to fatigue, lower the immune system, and can cause the serious condition of anemia. But having too much iron, called hemochromatosis - or - iron overload is also a problem, creating poisonous conditions for the liver, heart and pancreas. It can also cause cancer, heart arrhythmias and cirrhosis of the liver. Iron overload can be caused by genetic factors, and such is the case with sickle cell disease, affecting an estimated 70, 000 to 100,000 US citizens, the majority being African Americans. Iron overload is also prevalent in the disease called thalassemia - a group of genetic blood disorders. People with this disease cannot make normal hemoglobin to produce healthy red blood cells. If diagnosed and treated before organ damage has occurred iron overload patients can often grow and develop normally, with relatively normal heart and liver functions.