Lecture beta thalassemia Flashcards
Hemoglobinopathies Are—-
Inherited single gene disorders that affect hemoglobin production and function
It is estimated that around —of the world population carries a globin-gene mutation; and in the majority of cases, it is inherited as an ——trait.
7 percent/ autosomal recessivve
Hemoglobinopathies can be classified broadly as
Qualitative and quantitative disorders
Qualitative hemoglibinopathies result from —-while quantitative ones OR THALASSEMIAS result from—
α- or β-globin gene mutations that cause structural alterations in the Hb molecule./ mutations that cause decreased synthesis of otherwise normal α- or β-globin chains, resulting in imbalance of the subunits
Thalassemia is
an inherited disorder of hemoglobin synthesis that results in the reduction of the total hemoglobin in the body leading therefore to anemia.
The thalassemias are a ——- group of hereditary disorders of hemoglobin synthesis found worldwide, in many countries around the world and particularly in persons of —-
Heterogeneous/Mediterranean, African Asian ancestry
Thalassemia is derived from the words:
Thalassa” which in Greek means the sea. “emia” which is a disease of the blood.
Thalassemia means disease of the blood related to the sea.
It was previously thought that—- However, we now know that this group of anemias, although prevalent in the —— is present in many other areas and particularly in ——
this type of disease was confined to the Mediterranean Sea including Lebanon./ miditterenean basin/ southeast asia
Anemias can be due to
Difficulties in making heme ( Iron deficiency anemia) or problems in globin (Hemoglobinopathies
Thalassemias for instance are a group of disorders resulting from diminished production or complete absence of globin chain production. These are classified according to ——/ the main ones which have been defined with certainty are the
which globin chain is synthesized at a reduced rate. / alpha and beta thalassemias
In ß thalassemia, synthesis of the beta chain is defective. In α thalassemia, it is synthesis of the chain that is defective. Finally, with δ-β thalassemia, both δ and β chains are reduced. Both the alpha and beta chains are structurally —-the defect is ——
Normal/quantitative
Normally after the age of six months, we have the following normal hemoglobins:
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Genes control every characteristic of the body. One gene for each characteristic comes from the mother and the other from the father. Therefore, among many other genes, —-genes control how β globin is made inside the RBC and — α genes control how α globin is made inside the RBC.
2/4
the globin chain structural genes are located on chromosomes. There are ——copies of the hemoglobin alpha gene on each chromosome 16 or —-α genes per cell. In contrast, there is only —-ß gene on each chromosome 11 or ——ß genes per cell.
16 and 11/2 / four / one /2
Pic page 3 of order of genes on chromosomes
Normally —- are active in the production of globin chains.
all four α genes and both ß genes
In thalassemia, globin chain synthesis is absent or reduced because of—-
Mutation or deletion of the gene that codes for the globinn chain synthesis
The severity of symptoms of alpha thalassemia depends on —— Loss of one or two genes is ——, whereas deletion of all four genes is ——
How many of these genes are lost/ usually asymptomatic / fatal to the unborn child
In contrast, ——affect the ß genes, and ——
Over 100 types of mutations affect the beta genes and deletion mutations are rare
Some mutations tend to cause a ——Other mutations tend to cause ——-
reduction, rather than a complete absence, of β- globin chains and so result in milder disease. / total absence of β-globin chains leading to severe diseasecu
Currently, severe thalassemia is treated by ——and a minority of patients are cured by ——-. Mouse models are proving to be useful in assessing the potential of——-
Blood transfusions/ BM transplantation / gene therapy
In β thalassemia for instance, there is ——
partial or complete absence of beta chain production, therefore there is decreased or total absence of HbA.
Normal people are normal because they have two normal β genes for Hb.
Healthy carriers of beta thalassemia trait have one normal β gene for Hb and one
altered gene.
People with beta thalassemia major have two altered β genes for Hb.
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At present, thalassemia diseases are classified into —-
transfusion-dependent thalassemia (thalassemia major) and non-transfusion-dependent thalassemia (thalassemia intermedia).
