Anemia- Hypoplastic- Congenital
Diamond-Blackfan anemia is an inherited blood disorder that affects the ability of the bone marrow to produce red blood cells. It is usually diagnosed during the first year of life. Individuals with Diamond-Blackfan anemia may also have physical abnormalities of the face head, upper limbs, hands (mostly involving the thumbs), genitalia, urinary tract, and heart. Some affected individuals also have short stature.
This disease a macrocytic anemia resulting from congenital hypoplasia of the bone marrow, which is grossly deficient in erythroid precursors whereas other elements are normal; anemia is progressive and severe, but leukocyte and platelet counts are normal or slightly reduced; survival of transfused erythrocytes is normal; minor congenital anomalies are found in some patients. Both autosomal dominant and recessive forms have been described, caused by mutation in the gene encoding ribosomal protein S19 (RBS19) on chromosomal 19q. SYN: congenital nonregenerative anemia, Diamond-Blackfan anemia, Diamond-Blackfan syndrome, erythrogenesis imperfecta, familial hypoplastic anemia, pure red cell anemia.
- Growth retardation
- Failure of sexual maturation
- Decreased activity
- Low birth weight
- Infant pallor
Diamond-Blackfan anemia is caused by a mutation in a number of different gene(s), some of which have been identified and some of which have not. Identified genes include but are not limited to: RPS19, RPL5, RPS10, RPL11, RPL35A, RPS7, RPS17, RPS24, RPS26 and GATA1 genes. Different subtypes exist and are divided based on the specific gene mutated; however, they have similar features. Patients with mutations in the RPL5 gene have more serious symptoms and about 45% have cleft palate and are smaller than average size. Patients with mutations in the RPL11 gene have thumb anomalies more frequently than people with the other types. Mutations in the GATA1 gene are associated with severe anemia. About 45% of people with Diamond-Blackfan anemia inherit this condition from a parent. Inheritance is typically autosomal dominant , but can rarely be X-linked.
Diamond-Blackfan anemia is most commonly inherited in an autosomal dominant manner. This means that to be affected, a person only needs a change (mutation) in one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. A person with Diamond-Blackfan anemia has a 50% chance with each pregnancy of passing along the mutated gene to his or her child. Approximately one-half of affected individuals have inherited their mutation from a parent and about one-half have a new (de novo) mutation. People with Diamond-Blackfan anemia may not appear to have a family history of the condition if relatives have very mild signs and symptoms. In rare cases, Diamond-Blackfan anemia can be inherited in an X-linked manner.
Some people have such mild signs and symptoms that they do not require treatment. The majority of people who do require treatment because of low red blood cell counts are prescribed corticosteroids and have blood transfusions. Corticosteroid treatment is recommended in children over 1 year of age; this treatment can initially improve the red blood count in approximately 80% of people with Diamond-Blackfan anemia. Bone marrow/stem cell transplantation might also be considered and is the only curative treatment for the anemia; however, patients should continue to be followed because they are at increased risk for leukemia and cancer.