What Is Diamond Blackfan Anemia?

Definition:  

Diamond Blackfan Anemia (DBA) is an inherited anemia where the bone marrow cannot make sufficient amounts of red blood cells (called a pure red cell aplasia).  It is part of a larger group of disorders called inherited bone marrow failure syndromes.

What are the features of DBA?  

Almost all patients are diagnosed in the first year of life.  

• Anemia:  The anemia of DBA is severe and usually requires multiple blood transfusions.  
• Birth defects: Up to half of patients with DBA also have physical abnormalities.  The areas of the body most commonly affected are:
  • Head, neck, and face
  • Heart
  • Thumbs
  • Genital and urinary systems
  • Short stature
• Increased risk of cancer:  People with DBA appear to have an increased risk of cancer.  These include acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and solid tumors. 

What causes DBA?

DBA is an inherited bone marrow failure syndrome.  Almost half of cases are familial meaning the genetic mutation was passed down by a parent.  Other cases are sporadic, occurring randomly.  In familial forms, not all family members are equally affected.  A parent may have a mutation associated with DBA but not be diagnosed until after his/her child is diagnosed.  

All cells in the body have a certain lifespan and then undergo cell death under a very controlled process. In DBA a genetic mutation causes the stem cells (make red blood cells and the early red blood cells in the marrow) to self destruct faster than they should leading to decreased production of red blood cells.  

How is DBA diagnosed?  

The complete blood count (CBC) identifies the anemia and reveals larger than normal red blood cells (macrocytosis).  In general the anemia is isolated without changes in white blood cell or platelet count.  Reticulocyte count is low (reticulocytopenia) because the bone marrow is unable to compensate for this anemia.  

DBA must be distinguished from transient erythroblastopenia of childhood (TEC) which can present in the same age group but resolves spontaneously.  Specifically the fetal hemoglobin level and erythrocyte adenosine deaminase level are usually elevated in DBA but not in TEC.    

If someone is suspected to have DBA, genetic testing should be sent.  If a genetic mutation is identified, other family members should be tested given the increased risk of cancer.  

Sometimes a bone marrow aspirate and biopsy are performed to assess the environment where the red blood cells are made.  The bone marrow is usually normal except for a lack of the red blood cell precursors (early cells that develop into red blood cells).  

Standard diagnostic criteria are:

• Age less than 1 year
• Macrocytic (larger than normal) anemia without changes in white blood cell or platelet count
• Reticulocytopenia
• Normal bone marrow except for lack of red blood cell precursors

If a patient is suspected to have DBA but does not meet this diagnostic criteria, there are secondary criteria that can support a probable diagnosis.  

What are the treatments for DBA?

Although most patients require treatment up to 25% of patients will have spontaneous resolution.  

• Transfusions:  The anemia of DBA is severe and requires frequent blood transfusions.  This is the primary therapy until it is safe to start steroids.  
• Corticosteroids:  Oral steroids like prednisone/prednisolone are the backbone of therapy for children with DBA. Steroids are started and weaned to the lowest dose needed to eliminate need for transfusion.  If no response, transfusions are reinitiated.  
• Bone marrow transplantation:  Bone marrow transplantation can be curative.  Best results come from matched sibling donors.  Sibling donors must undergo genetic testing to ensure he/she does not have a mild form of DBA.