What is DBA?
Diamond Blackfan Anemia (DBA) was first recognized as a distinct entity in 1938, although it was called “congenital hypoplastic anemia” at that time. Diamond Blackfan Anemia (“DBA”) is a rare blood disorder, characterized by a failure of the bone marrow (the center of the bone where blood cells are made) to produce red blood cells. This failure causes DBA patients to become severely anemic. It is important to note that this anemia is not the result of a deficiency in iron, vitamin B-12, folate, or erythropoietin, which is a blood cell stimulating factor. Although a number of theories regarding the cause of DBA have been proposed, it is now widely accepted that DBA is a ribosomal protein disease. The disorder results from an intrinsic progenitor cell defect in which erythroid progenitors and precursors are highly sensitive to death by apoptosis (self-destruction).
Most DBA patients are diagnosed within the first year of life. Potentially, DBA patients can live long and healthy lives with appropriate medical treatment. The two most common forms of treatment are blood transfusion therapy and corticosteroid medication. Some DBA patients are in remission and need no medical treatment related to their DBA. Other DBA patients may choose to undergo the risky procedure of a stem cell transplant (also referred to as a bone marrow transplant).
In recent years, the scientific community has discovered numerous ribosomal protein gene mutations. This is a very exciting discovery for the DBA community, as it has resulted in increased scientific attention to this rare disorder. Advances in whole exam sequencing are expected to advance additional gene mutation discoveries.
Diamond Blackfan Anemia (“DBA”) is a rare blood disorder, characterized by a failure of the bone marrow.
Diamond Blackfan Anemia (“DBA”) is a rare blood disorder, characterized by a failure of the bone marrow.
However, there are other names for DBA that include:
Blackfan Diamond syndrome
Congenital pure red cell aplasia
Congenital hypoplastic anemia
Aase syndrome (felt to be a subset of DBA in which there is a finger-like thumb, and not a distinct disorder)
The two most common forms of treatment are blood transfusion therapy and corticosteroid medication
Diamond Blackfan Anemia is the preferred name.
Treatment
RESEARCH SUPPORT HIGHLIGHTS
We are a proud supporter of the DBA Foundation and the work that they are supporting through grants.
Because of our families’ continuous support, the DBAF has been able to fund many important research projects. These awards have been International, supporting research in England, France, Sweden, and Italy in addition to awards made here in the US. The international nature of these awards is important because for a rare disease like DBA there are typically too few researchers in a single country to truly push research forward.
With the current financial crisis affecting all quarters of our economy including both public and private enterprises, funding for virtually all types of research is likely to be adversely affected. Funding through the National Institutes of Health has been extremely tight in recent years. Fortunately, in 2004 the National Heart, Lung, and Blood Institute began a program to support research on the Molecular Mechanisms Underlying DBA and other Bone Marrow Failure Syndromes. This program provided a mechanism to ensure support for research on DBA despite the highly competitive environment for Federal research dollars. This support, together with research support from the Diamond Blackfan Anemia Foundation and the Daniella Maria Arturi Foundation, led to a period of unprecedented growth in our understanding of the molecular basis for DBA. It is unclear, however, whether the Federal Government will be able to continue its level of commitment to DBA research over the next few years. As such, the percentage of the total amount invested in DBA research that comes from private foundations will likely increase in the near future. Therefore, to maintain the momentum of the past 4 years towards gaining a better understanding of the molecular basis underlying DBA and more importantly, to begin to translate these discoveries into better treatments for children with DBA, the DBA Foundation needs your support now more than ever.
"DBA has affected our lives in ways we could have never imagined. It has introduced us to the most amazing people – from the dedicated doctors to the wonderful families who are also dealing with DBA. They all exemplify the power of the human spirit and our family."
- Early support for the DBA registry
- Support for clinical studies on DBA diagnosis, management, and treatment
- Support for the identification of DBA genes
- Support for studies on the role of ribosome synthesis defects in the pathophysiology of DBA
- Support for the creation of a zebrafish model of DBA
- Support for the creation of a mouse model
DIAGNOSIS
Diagnostic criteria for Diamond Blackfan Anemia taken from the International Clinical Care Consensus Document (2008):
Age less than 1 year
Macrocytic anemia with no other significant cytopenias
Reticulocytopenia
Normal marrow cellularity with a paucity of red cell precursors
Near normal, but variable, neutrophil and/or platelet counts
Supporting criteria:
Major
Gene mutation described in “classical” DBA
Positive family history
Minor
Elevated erythrocyte adenosine deaminase activity
Congenital anomalies are described in “classical” DBA (Congenital anomalies mainly involve the head, upper limbs, heart, and genitourinary system.)
Elevated HbF (fetal hemoglobin)
No evidence of another inherited bone marrow failure syndrome
The above diagnostic criteria define what is termed “classical” DBA, but DBA may also be present in “nonclassical” ways. For example, individuals may present at an age greater than one year, only with congenital anomalies, without anemia, or with a mild hematological phenotype (macrocytosis only). These cases of ‘‘non-classical’’ DBA need to be more carefully identified, particularly when reproductive choices and transplant donor decisions are being made. Furthermore, as the risk of malignancy and other complications of DBA are better defined, the necessity of making a diagnosis in ‘‘asymptomatic’’ individuals will become more important.
There are over 600 patients with DBA registered with the DBA Registry (“DBAR”). Each year, approximately 25 to 35 new cases of DBA will be diagnosed in the United States and Canada. DBA is an equal opportunity syndrome, affecting males and females and all ethnicities equally. Most patients are diagnosed with DBA within the first year of life.
According to the DBAR, the average age of presenting with anemia is two months and the average age of diagnosis with DBA is four and a half months. Patients with DBA typically present with common symptoms of anemia, including pale skin, sleepiness, irritability, rapid heartbeat, and heart murmurs.
There are several tests to aid in diagnosing DBA
Complete Blood Count (CBC): A test that determines the concentration and composition of cellular components of blood. Included in the CBC are values for the number of red blood cells, white blood cells, and platelets in a blood sample. Blood is typically drawn from a vein. In an infant or young child, blood may also be drawn from the heel, a toe, or a finger. A CBC measures many things, including the following values which are generally relevant to the DBA patient:
The number of red blood cells
The number of white blood cells and the percentage of each type present
The number and size of platelets
The total amount of hemoglobin in the blood
The fraction of the blood composed of red blood cells (“hematocrit”)
The size of the red blood cells is referred to as the mean corpuscular volume (“MCV”)
A CBC also includes other information about the red blood cells, including the mean corpuscular hemoglobin (“MCH”) and mean corpuscular hemoglobin concentration (“MCHC”)
TREATMENT OPTIONS
BLOOD TRANSFUSIONS
One type of treatment that might be recommended for someone with DBA is blood transfusions. Blood transfusions might be recommended just as needed when the hemoglobin is lower than normal, or as a chronic blood transfusion program. Chronic blood transfusions consist of scheduled blood transfusions every 3-6 weeks to maintain the hemoglobin level in a safe range. A DBA patient normally makes his or her own white blood cells and platelets, and therefore would only require a transfusion of red blood cells.
Blood transfusions are typically given in a hospital setting. Before a transfusion, a small amount of blood will be drawn from the patient for “typing and screening.” Typing refers to the type of blood the patient has (A, B, AB, or O) and screening refers to identifying whether certain antibodies are present. Generally, people must receive blood of their same type to avoid severe transfusion reactions. These tests are followed by the compatibility testing (cross-match). This test ensures that no antibodies are detected in the recipient’s serum that will react with the donor’s red blood cells. Generally, when patients receive a blood transfusion, they receive blood that has been donated from the general population. In the United States, the blood supply is considered to be safe. The federal Food and Drug Administration (“FDA”) is responsible for ensuring the safety of the blood industry in the United States.
STEM CELL TRANSPLANT
Another type of treatment for DBA is to undergo a stem cell transplant. Stem cell transplants (“SCT”) are also known as bone marrow or cord blood or peripheral blood stem cell transplantation (depending on the donor source). A SCT involves replacing a DBA patient’s unhealthy bone marrow with healthy cells from a donor. The donor’s stem cells can be obtained from bone marrow, peripheral blood, or cord blood. This is a complicated medical procedure that requires several months in the hospital and is not without risk. The reward for a successful bone marrow transplant is that the patient’s bone marrow will function normally and the patient will not need chronic blood transfusion therapy or corticosteroid medication.
Stem cell transplantation (SCT) is a potentially curative but dangerous procedure. The role of transplantation for patients with DBA remains complex and controversial. In general, whether steroid-responsive or transfusion-dependent, patients with DBA may be considered for transplant before the age of ten years, and preferably between the ages of 2 and 5 years, if an HLA-matched related donor is available. As of the last published analysis, most sibling transplants used chemotherapy alone as a conditioning regimen, while most of the alternative donor (mismatched family or unrelated donor) transplants used a combination of chemotherapy with radiation therapy for pre-transplant conditioning. Data from the DBAR show overall survival of 77% for allogeneic sibling SCT (94% for allogeneic sibling SCT age nine years and less) and 36% for alternative donor SCT (86% for alternative SCT done after 2000).
