Sideroblastic anemia

Sideroblastic anemia is a type of anemia in which a person's bone marrow produces precursors to red blood cells, called sideroblasts, instead of fully formed healthy red blood cells. This condition leads to an improper use of the iron found in red blood cells and in turn leads to irregular hemoglobin production. These problems cause a build-up of iron in the blood, which gives a ringed appearance to the nucleus of the blood cell as iron-loaded mitochondria gather around it. The presence of ringed sideroblasts characterize the diagnosis of sideroblastic anemia. Sideroblastic anemia can be acquired or inherited. Acquired sideroblastic anemia is caused by issues such as toxin exposure and alcoholism. Inherited sideroblastic anemia is caused by genetic factors such as gene mutations. Signs and symptoms of the condition include fatigue, weakness, headaches, chest pain, breathing problems, and enlargement of the liver or spleen. In some cases, more severe issues may develop, such as leukemia. Treatment depends on whether the condition is inherited or acquired.

Background

Anemia is a medical condition in which a person's blood does not contain enough red blood cells or hemoglobin, a type of protein found in red blood cells that contains iron and binds oxygen. Low amounts of red blood cells or hemoglobin can mean your body does not get enough oxygen. This can cause a range of bodily symptoms, from fatigue to dizziness to cramping to insomnia. More severe symptoms include abdominal pain, discolored urine, jaundice, seizures, and kidney failure. Blood iron levels can also become problematic with anemia, and, depending on the type of anemia, a person can have too much or too little iron in the blood.

Anemia is the most common blood condition in the United States, affecting approximately 5.6 percent of Americans. Women, young children, and those with chronic diseases have an increased risk of developing anemia. Women in their childbearing years are particularly susceptible to developing anemia due to blood loss from menstruation and an increase in blood supply needs during pregnancy. Elderly people also have an increased risk due to medical conditions associated with old age and poor diet.

More than four hundred types of anemia exist and they are divided into three groups: anemia caused by blood loss, anemia caused by a reduction or malfunction in red blood cell production, and anemia caused by damage to red blood cells. Sideroblastic anemia is a type of anemia caused by a malfunction in red blood cell production. People with sideroblastic anemia produce abnormal red blood cells that contain too much iron. This excess of iron impairs the cell's ability to produce hemoglobin effectively.

Overview

Sideroblastic anemia can be caused by hereditary factors, exposure to drugs or toxins, or emerge as part of an underlying condition. The condition is often divided into inherited sideroblastic anemia and acquired sideroblastic anemia. Inherited sideroblastic anemia is rare and involves several possible hereditary causes. These causes include specific gene mutations, mutations to a person's mitochondrial DNA, and inherited metabolic disorders. The most common type of inherited sideroblastic anemia is X-linked sideroblastic anemia, which involves mutations in the gene involved in normal hemoglobin production. The mutation disrupts this process and causes the body to absorb more iron from food, leading to a surplus of iron in the blood. Inherited sideroblastic anemia can lead to organ damage, specifically liver damage. This type of sideroblastic anemia is most common in males and onset of the disorder usually occurs before the age of thirty.

Acquired sideroblastic anemia is more common and is usually reversible. Acquired causes include having a blood disorder that leads to abnormal development of blood cells within bone marrow, immune disorders, metabolic diseases, nutritional deficiencies, too much zinc intake, lead poisoning, tumors, and hypothermia. Certain types of drugs can also lead to acquired sideroblastic anemia, such as anti-tuberculous agents, progesterone pills, antibiotics, and specific types of cancer drugs. People can also get this type of sideroblastic anemia from drinking excessive amounts of alcohol. Acquired sideroblastic anemia is most often seen in older patients of both genders 65 years old or older.

Diagnosis of sideroblastic anemia may include blood work, bone marrow biopsy, and brain-imaging tests such as magnetic resonance imaging (MRI). Genetic testing can also be performed to check for known or suspected hereditary conditions related to sideroblastic anemia. People with acquired sideroblastic anemia have a small chance of getting leukemia, with about ten percent of people developing the disease. Individuals with either acquired or inherited sideroblastic anemia are also at risk of developing hemochromatosis, a disorder in which too much iron builds up in the organs, specifically the liver, heart, and pancreas. This can lead to life-threatening diseases.

Treatment for sideroblastic anemia depends on whether an individual has inherited or acquired sideroblastic anemia. For either condition, doctors often prescribe vitamin B6 supplements, also known as pyridoxine. Research suggests vitamin B6 improves red blood cell production efficiency and in some cases vitamin B6 supplementation can reverse the anemia. For acquired cases of sideroblastic anemia, the patient must remove the toxin or medication causing the anemia and avoid these causative agents as much as possible. Doctors may also suggest a blood transfusion, but this treatment may actually worsen iron overload in the blood if the process is not monitored carefully. Patients may require repeated blood transfusion to maintain normal levels of hemoglobin in the blood. Medical professionals will monitor a patient's symptoms during and after transfusion to assess the need for continued transfusion. In rare cases, a bone marrow transplant may be necessary, although this treatment is also associated with potential complications. Patients with sideroblastic anemia should avoid all supplements containing zinc and should refrain from drinking alcohol.

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