Diamond-Blackfan anemia (DBA) is a genetic disorder in which the body does not produce red blood cells to circulate oxygen to the body. With symptoms similar to general anemia, this disorder is more complex. Though it can be life-threatening, there do appear to be several treatments that are effective for most people who have the disorder.
Definition & Facts
Diamond-Blackfan anemia is a rare blood disorder. First described in 1938 by Boston Children’s Hospital doctors Kenneth Blackfan and Louis Diamond, DBA is also a congenital disorder. Patients with DBA have bone marrow that does not make red blood cells as it should.
Red blood cells are needed to carry oxygen from the lungs to the rest of the body. Patients with DBA typically have severe anemia and other characteristic deformities that are caused by the anemia. DBA is a potentially life-threatening condition.
Symptoms & Complaints
Generally, babies and children will appear to have very pale skin as their oxygen levels are reduced throughout the body. They may tire easily, and infants may even fall asleep before they are finished feeding.
Due to the lack of oxygen circulating in their bodies, and possibly because of getting less nutrients when they are too tired to feed, these babies and children lack the energy of their typical peers. In addition, the patients may appear to have a hard time breathing, even when not exerting any excess energy.
About 40 percent of all DBA patients will also exhibit some unusual physical characteristics. For example, they may weigh less than they should at birth and remain particularly short, even falling off of the normal growth charts.
Head, face, and neck abnormalities may be seen as bones may fuse where they are not supposed to be fused, particularly in the cervical vertebrae. Additionally, they may have wide set eyes, droopy eyelids, small ears, and some individuals may have a cleft lip and cleft palate.
Thumb and upper limb defects are also more common in individuals with DBA. Finally, congenital heart defects and kidney defects as well as urogenital malformations, may make up the most severe physical flaws.
DBA is a genetic defect. In some cases, children with DBA have a family member that has also had the disorder, but this is not true of all cases. Genetic factors that have been identified appear to be linked to genes that produce ribosomes. Ribosomes are small particles found in large numbers in the cytoplasm of living human cells. They contain RNA and proteins and play a role in the building of the body’s proteins.
More than half of all children with DBA have a mutation of a ribosomal gene, and at least 11 such mutations have been identified. Additionally, in boys, there have been rare cases of a mutation in another gene that controls the earliest development of red blood cells. However, many other children with DBA do not have abnormal genes that have been identified. The cause of their DBA is unknown.
Diagnosis & Tests
Most children with DBA will experience at least some symptoms very early in life. By two months of age, there may be enough evidence to determine that something is wrong with the baby, and further testing is needed. DBA is usually diagnosed before a child’s first birthday, but it can also be diagnosed later in life if symptoms are mild or are not properly considered. Additionally, the child’s doctor may suspect a problem after routine blood testing comes back with a low red blood cell count.
Still, two tests are required for a definitive diagnosis, and these include blood testing and bone marrow testing. Blood test results that are consistent with DBA will show anemia before age one, larger than normal red blood cells, normal white cell counts and platelet counts, and not enough newly made red blood cells. Bone marrow testing will show that there are few cells that will develop into red blood cells. Other indications of the disease include a family history of the disorder, genetic testing showing the DBA abnormalities or mutations, and the presence of physical birth defects.
Treatment & Therapy
There are some treatments that appear to be effective in abating symptoms and sometimes curing DBA. The first course of action in most cases is a corticosteroid medication. These medicines are strong anti-inflammatories. It is not known exactly why steroids work, but, in about 80 percent of patients, it does help them to start producing more red blood cells.
In addition, or if steroids do not work, some babies and children receive blood transfusions. Blood has to be matched to the recipient, and it allows the patient to have red blood cells to carry oxygen throughout the body. A person can get a transfusion every four to six weeks though there can be complications if too many transfusions are given.
Finally, stem cell treatment can help some individuals. Again, the bone marrow has to be a matched for the recipient, and the best match is often a close family member. Bone marrow matching is much harder than blood matching, so it is sometimes a lengthy process to find a proper donor.
Once the right donor is found, stem cells are taken from the donor and put into the DBA patient. These healthy stem cells can turn into any type of blood cell and often cure a person’s DBA. Nonetheless, rejection and infection are big concerns so this is typically only used if steroids and transfusions are not effective.
Prevention & Prophylaxis