ICD-10 D56.2 MeSH D055538 | ICD-9-CM 282.45 | |
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Delta-beta thalassemia is a form of thalassemia, and is autosomal recessive in terms of heredity. It is associated with hemoglobin subunit delta
Contents
Signs/symptoms
An individual with delta-beta thalassemia is usually asymptomatic, however there can be microcytosis where the red blood cells are abnormally small.
Mechanism
In regards to genetics, delta-beta thalassemia is autosomal recessive, which means both parents (two copies of the gene) must be present. A carrier gets a normal gene to produce hemoglobin A, from one parent and the other parent supplies a gene which makes no hemoglobin A. Delta-beta thalassemia is considered rare.
In terms of the pathophysiology of delta-beta thalassemia, one finds delta and beta chains have deletion, therefore gamma genes are what is transcribed (made an RNA copy of) on the impaired chromosome.
When one inherits two delta0 mutations, no hemoglobin A2 (alpha2,delta2) can be formed. Hematologically, however, this is innocuous because only 2-3% of normal adult hemoglobin is hemoglobin A2. The individual will have normal hematological parameters (erythrocyte count, total hemoglobin, mean corpuscular volume). The delta-beta thalassemia demonstrates one mutation is at the +69 position.
Relation to beta thalassemia
The importance of recognizing the existence of delta-beta thalassemia is seen best in cases where it may mask the diagnosis of beta thalassemia trait. In beta thalassemia, there is an increase in hemoglobin A2. However, the co-existence of a delta-beta thalassemia mutation will decrease the value of the hemoglobin A2 into the normal range, thereby obscuring the diagnosis of beta thalassemia trait
Diagnosis
The diagnosis of delta-beta thalassemia is done via hypochromic microcytic red cell indices. This test is a part of a CBC, and could be employed to diagnose the reason the individual might have anemia, in this case due to thalassemia.
Treatment
In terms of treatment for delta-beta thalassemia one possible concern would be anemia, where therefore blood transfusions would be given to the affected individual (though blood transfusions might introduce complications, as well).
Stem cell transplant is another option, however the donor and the individual who will receive the bone marrow transplant, must be compatible, the risks involved should be evaluated as well