Alpha -thalassemia

August 12, 2017 17:51 | Genetic Diseases


4 genes that control the formation in humans α-globin chains.In the absence of α-chain is not synthesized in the fetus fetal hemoglobin, developed dropsy, and then death occurs.If any of function 1 or 2 genes anemia, in most cases, non-severe.Manifestations of α-thalassemia gene with the defeat 2 depend on which genes are amazed and almost completely repeated heterozygous β-thalassemia.Often increases the size of the spleen, at least - the liver.Determined mild anemia, a slight increase in the level of reticulocytes (immature forms of red blood cells), a slight increase of bilirubin in the blood and increase serum iron.Normally, blood relatives have the same anemia.

However, unlike the β-thalassemia, α-thalassemia when not increasing the number of fetal hemoglobin and hemoglobin A.

α-thalassemia can be detected only in the study of the formation of the globin chains in vitro, which is performed in specialized laboratories, α-thalassemia sometimesIt can be detected in newborns at a blood test by


hemoglobinopathies H - a variant of α-thalassemia.It is relatively non-severe, manifested a significant enlargement of the spleen and liver, jaundice small by increasing the amount of bilirubin, anemia of varying severity, but most of the hemoglobin content of not less than 70-80 g / l.Hemoglobinopathies H differs from other forms of thalassemia by multiple small inclusions in all red blood cells, which are visible under a microscope when stained with red blood cells.


A-β-thalassemia is accompanied by a violation of the synthesis of both α-, and β-globin protein chains.According to its manifestations heterozygous αβ-thalassemia is not different from the heterozygous β-thalassemia.Typically, when β-thalassemia is heterozygous increased the amount of hemoglobin A. However, hemoglobin A contains α-chain and therefore when combined β- and α-thalassemia have most typical laboratory β-thalassemia trait - increase hemoglobin A. often found with increasing hemoglobinF under normal or a reduced amount of hemoglobin A (the so-called HbF-thalassemia).In homozygous β-thalassemia, combined with α-thalassemia, the child has only hemoglobin F, B while the hemoglobin A, or very little, or do not.