Diamond Blackfan Anemia (DBA)

What is Diamond-Blackfan anemia?

Diamond-Blackfan anemia (DBA) is a rare genetic blood disorder. Symptoms start appearing early in life. Children with DBA have bone marrow that does not make enough red blood cells. A part of red blood cells called hemoglobin carries oxygen to the whole body. When the number of red blood cells is low, anemia develops and the body cannot work at a normal pace.

What are the symptoms of Diamond Blackfan anemia?

Clinical features of DBA vary and can range from severe to mild or even asymptomatic. Anemia is usually the first symptom of DBA. It can cause:

• Pale skin
• Sleepiness and fatigue
• Fast heartbeat
• Headaches

Children with DBA may also be born with one or more of these physical issues:

• Distinct features of the face, head and neck
  • Small head size (microcephaly)
  • Wide-set eyes (hypertelorism)
  • Droopy eyelids (ptosis)
  • A broad, flat nose
  • Small, low-set ears
  • Small lower jaw (micrognathia, Pierre-Robin sequence)
  • Opening in the roof of the mouth (cleft palate) with or without a split in the upper lip (cleft lip)
  • A short, webbed neck
•  Altered or missing thumbs
• Heart defects
• Defects of the kidneys and/or genitals
• Low birth weight and failure to thrive

These problems can be part of DBA but also arise as side effects of therapies:

• Short height
• Delayed puberty
• Eye problems
  • Clouding of the lens of the eyes (cataracts)
  • Increased pressure in the eyes (glaucoma)

DBA can also increase the risk of cancers that occur later in life:

• Colorectal cancer
• Osteosarcoma, a cancer of the bone
• Myelodysplastic syndromes (MDS), a disorder in which the stem cells in the bone marrow do not work well and are pre-cancerous
• Acute myeloid leukemia (AML), a cancer of the bone marrow

How common is Diamond Blackfan anemia?

DBA is rare. It affects about 5 to 7 newborn babies per million worldwide. About 40 children in the United States and Canada are newly diagnosed with DBA each year. More than 2,000 DBA patients are currently followed in US and European DBA registries.

DBA occurs in equal numbers in both boys and girls. It can appear at any age, but most often it is found before the child’s first birthday.

What causes Diamond Blackfan anemia?

DBA is a genetic disorder caused by a mutation (change in the DNA) in one of more than 30 genes. These genes are responsible for normal functioning of the ribosomes. Ribosomes are considered protein factories in every cell. Similar to DNA, proteins are essential building blocks of our body. It is thought that not enough functioning ribosomes in the stem cells causes the red blood cell system to fail in DBA.

The most common genes affected in DBA patients are RPS19, RPL5, RPL11, RPL35a, RPS10, RPS26 and RPS24. ADA2 deficiency is a rare disease that also can be present with severe anemia similar to DBA. As of 2020, about 25% of children with DBA have an unknown genetic cause.

In many families, the gene change that causes DBA is passed from parent to child. If one parent has the gene change, there is typically a 50% chance that it will be passed to the child. Within the same family we often see different symptoms in carriers of the DBA-causing gene change. For example, while one sibling with the gene change might have mild symptoms and not require any therapy, another sibling might need blood transfusions throughout life. In at least one third of those with DBA, the gene change is not found in either parent and is new to the family.

How is Diamond Blackfan anemia diagnosed?

DBA can be diagnosed with these medical tests:

• Complete blood count (CBC) with reticulocytes
  A small sample of blood is taken from the child’s vein. The staff counts the different types of blood cells. Children with DBA will usually have low hemoglobin and reduced red blood cells (RBC) and reticulocytes (immature blood cells). The numbers of white blood cells and platelets are usually normal.
• Bone marrow aspiration and biopsy
  The child is usually given anesthesia, to fall asleep and make the procedure painless. A thin, hollow needle is put into a bone in the hip (or lower leg in very young children). Then, a small amount of bone marrow is removed. In patients with DBA the RBC progenitor cells are missing or severely reduced in the bone marrow. RBC progenitor cells are young cells that become red blood cells.
• Genetic testing
  Genetic testing is typically completed by taking a blood sample. Finding a gene change in one of the DBA genes would confirm the diagnosis of DBA. However, in about 25% of DBA patients with no known gene changes, the diagnosis is based on clinical findings.
• Other testing  
  Other specialized blood tests may be helpful in the diagnosis of DBA. These include an erythrocyte adenosine deaminase activity level (eADA) and fetal hemoglobin level (HbF). The eADA and HbF numbers are often higher in patients with DBA.

How is Diamond Blackfan anemia treated?

The most common treatments for DBA are corticosteroid therapy, blood transfusions and allogeneic bone marrow transplants.

Corticosteroid therapy

Prescription steroid medicines may be given to help the child’s bone marrow create red blood cells. Children younger than 1 year of age are not given steroids due to side effects. Some side effects can affect their growth.

Most children with DBA who take corticosteroids in the beginning show response. This means they will have more hemoglobin and reticulocytes. Due to corticosteroid side effects, the dose must be decreased over several weeks. After a while, corticosteroid therapy may stop working or does not work at lower doses. Currently, experts do not recommend more than 0.2–0.3 mg/kg per day as long-term therapy because of the severe side effects often visible only later in life. These side effects include osteoporosis (weak bones), breaking bones, weight gain, high blood pressure, diabetes and weak immune system. Patients who fail corticosteroid treatment will require blood transfusions.

Blood transfusion (red blood cell transfusion)

In a blood transfusion, healthy red blood cells from one person are given to another person. Transfusions are used to increase the number of red blood cells and hemoglobin in a person with DBA.

A blood transfusion is used:

• when anemia is severe,
• when steroid therapy doesn’t work, or
• when the patient cannot tolerate side effects of other treatments.

The transfused blood is given into a vein through an IV or a port, a tiny device placed under the skin. Transfusions usually must be repeated every three weeks and over time lead to iron overload in the body. Iron deposits in organs such as liver, heart and pancreas and can cause damage if not removed properly. For iron removal, patients take daily medicines that help remove the iron from the body (iron chelators).

Allogeneic bone marrow transplant

This treatment involves replacing the DBA patient’s unhealthy bone marrow with healthy cells from a donor, such as a family member or a matched unrelated donor. A stem cell transplant can cure DBA for life. However, in some patients it can cause side effects such as:

• an immune system reaction against the body (graft-versus-host disease),
• severe infections during transplant or
• the body rejecting the donor cells.

The long-term overall survival after transplant in children with DBA is higher than 90%. Currently, experts recommend transplant only when two repeated corticosteroids trials have not worked, and the child will likely need blood transfusions throughout life.

Are there any emerging therapies for Diamond Blackfan anemia?

Leucine

Leucine is an essential amino acid that can be taken as a dietary supplement. Based on experiments in mouse and zebrafish models, researchers believe that leucine can improve blood production in DBA patients. However, currently there is not enough data to support its use for DBA. Preliminary results from ongoing clinical trials do not show clear benefit from this drug and more data is needed to make a conclusion. Therefore, we currently do not recommend this as a standard therapy.

What are the survival rates of Diamond Blackfan anemia?

Children with DBA can live long lives with treatments. Some people treated for DBA achieve complete remission and do not need treatment, meaning their symptoms go away for more than six months. This can last for years and can become permanent. If symptoms eventually come back, it is called relapse, and patients require transfusions again.

What are the complications of Diamond Blackfan anemia?

DBA complications include health problems related to physical defects (such as heart or bone problems) or slow growth. Iron overload caused by transfusions can cause organ damage if the iron is not removed early on using drugs that help remove it. A small number of DBA patients might suffer myelodysplastic syndrome  (MDS), acute myeloid leukemia (AML) or other cancers later in life.

How will Diamond Blackfan anemia affect my child’s life?

Children with DBA require frequent visits to the doctor and may require hospital stays for disease complications throughout their lives. This may result in missed days of school and missed days of work for their caregivers. However, in general, children with DBA can lead normal lives and attend school or work.

When should I call my doctor?

Call the doctor if your child:

• Looks pale, has trouble breathing or is more tired than usual
• Before traveling on a plane or to the mountains
• Before any procedures using anesthesia, such as surgeries

Why choose St. Jude for your child’s Diamond Blackfan anemia treatment?

• St. Jude has a team of renowned experts who specialize in bone marrow failure and MDS. These experts work with other specialists around the world.
• The nurse-to-patient ratio at St. Jude is unmatched — averaging 1:3 in hematology and oncology, and 1:1 in the Intensive Care Unit.
• St. Jude offers children with blood disorders exceptional care. We also provide your family with the support you need to address physical, emotional, psychological, educational and other challenges while managing your child’s blood disorder.
• Our medical team works closely with laboratory researchers to better understand the disease causes. Together, they bring new treatments from the laboratory to the clinic.
• St. Jude doctors are engaged in the latest research studies, and patients are offered the choice to take part when studies are available. By performing these studies, we hope to better understand and treat blood disorders.