Diamond–Blackfan anemia

Diamond–Blackfan anemia
ICD-10	D61.0
ICD-9	284.01
DiseasesDB	29062
MedlinePlus
eMedicine	article/205695-overview
MeSH ID	D029503

Diamond–Blackfan anemia (DBA) is a rare congenital disorder, primarily recognized by its impact on red blood cell production, presenting often in infancy. While the anemia is its hallmark, many patients may also exhibit various congenital abnormalities.

Introduction

DBA, also known under the names Blackfan–Diamond anemia and Inherited erythroblastopenia, is a type of congenital erythroid aplasia. The anemia observed in these patients stands out as other blood cells, such as platelets and white blood cells, typically remain within normal ranges. This contrasts with conditions like Shwachman–Bodian–Diamond syndrome and Fanconi anemia, which affect other cell lines in different ways.

Clinical Features

• Anemia: DBA is typified by anemia, which is caused by a decrease in erythroid progenitors within the bone marrow. This condition typically manifests during the neonatal period.
• Congenital Abnormalities: About 47% of individuals diagnosed with DBA have been found to have a variety of congenital defects, ranging from craniofacial malformations to cardiac and urogenital defects. Some patients may also display cleft palate, low birth weight, and delayed growth.
• Risk of Malignancies: DBA patients have an increased risk of developing conditions like leukemia among other malignancies.

Diagnosis

Diagnosis of DBA revolves around detecting anemia and assessing the count of reticulocytes (immature red blood cells). The bone marrow typically shows reduced erythroid precursors. Additional supportive diagnostic criteria include:

• The presence of congenital abnormalities
• Macrocytosis
• Elevated fetal hemoglobin levels
• Increased levels of adenosine deaminase in red blood cells

The majority of patients are diagnosed before the age of two. A genetic test looking for mutations in the RPS19 gene can diagnose 20-25% of DBA cases.

Historical Background

The condition was first described in 1938 by Diamond and Blackfan as congenital hypoplastic anemia. Over the years, its association with skeletal abnormalities became clearer, culminating in the identification of the associated gene mutations by the end of the 20th century.

Genetics

DBA exhibits a pattern of genetic heterogeneity. While 10–25% of cases have a family history, most suggest an autosomal dominant inheritance. Current understanding indicates at least three genes may be implicated in DBA.

Molecular Basis

The disease primarily impacts the erythroid progenitor cells. One key DBA gene, RPS19, plays a role in ribosome production, which would suggest a broader impact. However, DBA presents dominantly, likely due to a partial loss of RPS19 function, with erythroid progenitors being particularly sensitive to this loss.

Clinical Management and Treatments

DBA's main treatment avenues are:

• Corticosteroids: These can treat anemia in DBA, with about 82% of patients initially responding. However, efficacy might decrease over time, and side effects are common.
• Blood transfusions: Useful for severe anemia, though prolonged use may lead to iron overload.
• Bone marrow transplantation (BMT): Can address hematological issues in DBA, but is not without risks.

Recent studies have indicated the potential benefits of dietary supplements, specifically amino acids like leucine and isoleucine, in treating DBA.

See Also

• Congenital disorders
• Anemia
• Blood transfusion
• Bone marrow transplantation

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