What Is Sideroblastic Anemia?

Red blood cells have a ringed appearance

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Sideroblastic anemia occurs when iron is not properly incorporated into the red blood cells. It can develop due to hereditary conditions or due to certain medical problems. "Anemia" is a general term for conditions in which there are lower numbers of healthy red blood cells than normal or they don't carry oxygen efficiently.

This condition can cause symptoms commonly associated with most types of anemia, such as fatigue and light-headedness. The diagnosis of sideroblastic anemia involves blood tests that evaluate characteristics of red blood cells, and other diagnostic tests can help identify the cause.

Treatment can help improve symptoms and may help alleviate the underlying cause. You will likely need follow-up testing to monitor the effects of your treatment and to determine whether you need additional tests. 

Woman experiencing fatigue

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Types of Sideroblastic Anemia

Sideroblastic anemia can be inherited or acquired. When it’s acquired, it develops due to a nonhereditary cause. Each of these types includes many subtypes, as follows:

  • Inherited: There are several types of hereditary sideroblastic anemia, with different inheritance patterns and different genetic mutations. Genetic changes that affect production or transportation of hemoglobin (which carries oxygen), iron, or certain mitochondrial proteins (found in the cell's powerhouses) can cause the condition.
  • Acquired: You can develop sideroblastic anemia due to medical conditions, nutritional deficiencies, toxins, or medications. 

Symptoms are similar for most types of sideroblastic anemia, and the severity can vary. Treatment is guided by the severity and the type. 

Sideroblastic Anemia Symptoms

Sideroblastic anemia can cause gradually progressive symptoms. As with most types of anemia, the effects are generally vague, and they may affect your day-to-day life. 

Common symptoms include:

  • Fatigue
  • Lack of energy
  • Pale skin 
  • Bronze appearing skin 
  • Jaundice (yellowing of skin and whites of the eyes)
  • Headaches and irritability 
  • Light-headedness and dizziness 
  • Abdominal distension (enlargement) due to an enlarged spleen or liver
  • Trouble concentrating 

These symptoms can be bothersome, but since they're often subtle, many people may not recognize that they are signs of a medical problem.

When to See a Doctor

Make sure to get medical attention if you have lingering symptoms of low energy.

In addition to the symptoms of anemia, you can also have other symptoms associated with the condition causing it.

Causes of Sideroblastic Anemia 

There are many different causes of sideroblastic anemia. These conditions interfere with the formation of hemoglobin, an iron-containing protein that binds to oxygen in the red blood cells. Hemoglobin picks up oxygen in the lungs when you inhale, and it releases it to all of your body’s organs so you can get energy.

When hemoglobin isn’t properly formed, iron builds up in red blood cells, but it isn’t useful. This leads to low oxygenation of tissues throughout your body, which causes many of the symptoms of sideroblastic anemia.

Causes of acquired sideroblastic anemia include:

  • Cancer
  • Myelodysplastic syndrome (affects how the bone marrow produces blood cells)
  • Vitamin B6 deficiency
  • Copper deficiency
  • Lead toxicity
  • Medications, including some antibiotics, chemotherapeutics, and chelators (medications used to remove excess metal from the body)

At least 25 different hereditary gene mutations have been identified in relation to hereditary sideroblastic anemia. Many of these are X-linked mutations (present on the X chromosome) or autosomal recessive (present on chromosomes other than X and Y, and the mutation must be inherited from both genetic parents to produce the condition).

These varied conditions can affect the transport of iron into the hemoglobin protein or may affect the production of hemoglobin. Iron accumulates in the red blood cells, and iron overload may develop in addition to the diminished red blood cell function.

How Is Sideroblastic Anemia Diagnosed? 

Often, sideroblastic anemia doesn’t cause physical changes that would be detected with a physical examination. Sometimes it can cause a rapid pulse, shortness of breath, skin color changes, or an enlarged abdomen and a palpable spleen or liver (your doctor can feel these organs by pressing gently on your abdomen).

These physical signs are not always present with sideroblastic anemia, and they are considered nonspecific—which means that many different medical issues can cause them. 

This type of anemia is diagnosed with blood tests. A complete blood count (CBC) is a common blood test that is usually part of a routine checkup. It is also often ordered when a person has symptoms of illness, such as fatigue. A blood smear, which is a microscopic examination of a blood sample, can diagnose sideroblastic anemia.

If you have signs of sideroblastic anemia in your blood tests, you may have additional diagnostic testing to identify the cause. 

Possible CBC changes:

Blood smear: Iron accumulation in the red blood cells makes a ringed appearance. This can be detected when the blood sample is observed microscopically using Prussian blue staining, a dye used to detect iron.

Other tests can include:

  • Genetic testing if there is a possible hereditary cause
  • Lead level if lead toxicity is a possibility
  • Bone marrow sample
  • Tests for vitamin B6 or copper deficiency
  • A test to assess whether there is iron overload

If you have a medical problem causing sideroblastic anemia, you may also have other effects that are related to the cause. For example, lead toxicity can cause cognitive deficits (difficulties in thinking and processing information), and your doctors will also treat the other effects of your condition.

Treatment of Sideroblastic Anemia 

The treatment of sideroblastic anemia includes approaches to improving the red blood cell and hemoglobin concentration in the blood, treating the underlying problem, and management of treatment side effects. 

In general, alcohol and zinc may worsen sideroblastic anemia. Avoiding these substances is recommended for anyone who has the condition.

Some treatments that are used include:

  • Vitamin B6 intake or supplements: This treatment is used for sideroblastic anemia that is caused by vitamin B6 deficiency, as well as for treatment of congenital sideroblastic anemia. You can get more of this vitamin by eating seafood, meat, chicken, some fruits and vegetables, and foods that are fortified with the vitamin.
  • Copper intake: This mineral is found in shellfish, nuts, beans, and grains, or your doctor may prescribe a supplement.
  • Lead chelation: Drugs that bind to lead so it can be eliminated from the body may be used for people who have severe lead toxicity.
  • Blood transfusion: Severe sideroblastic anemia may improve temporarily with the transfusion of healthy blood. Iron overload can be a side effect of this treatment, and chelation may be needed to remove excess iron. 
  • Bone marrow transplant: This treatment involves suppression of bone marrow activity with medication and then transplant of stem cells by infusion.
  • Research: Vidaza (azacitidine), a medication used in chemotherapy, has been used in research trials as a potential therapy for sideroblastic anemia.

Summary 

Sideroblastic anemia includes all types of anemia that cause ringed sideroblasts in the blood cells. These sideroblasts develop when the iron in the body can’t be incorporated into hemoglobin. The condition can cause symptoms ranging from mild to severe, such as fatigue, shortness of breath, and enlarged spleen.

Sideroblastic anemia can be caused by hereditary blood disease, medication side effects, medical conditions, and nutritional deficiencies. The diagnosis is made if a microscopic examination of the red blood cells shows ringed sideroblasts. It’s important for the cause to be identified so that treatment can be started.

Many people who have sideroblastic anemia require ongoing treatment and close observation with repeat blood tests. 

A Word From Verywell

Sideroblastic anemia is an uncommon type of anemia with characteristic diagnostic features. There are many causes of this type of anemia, and if you are diagnosed with sideroblastic anemia, this diagnosis is only the first step in your medical evaluation.

Your medical team will also need to identify the underlying cause so you can get started on the right treatment. You will need to have blood tests to monitor the effects of your treatment, and it’s also important that you stay attuned to your symptoms so you can get medical attention if your anemia recurs or worsens. 

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.