الوصف
In α- Thalassemia, Haemoglobin (Hb) H forms intracellular precipitates that result in early cell death. Haemolysis rather than ineffective erythropoiesis is the primary cause of anaemia. Many patients require intermittent transfusions. The clinical severity is strongly influenced by the type of a globin gene mutation. There are four genetic loci for α- globin; two on each chromosome The rate of synthesis of α-globin chains is related to the number of genes deleted. Loss of one α- globin gene (heterozygous α+ Thalassemia; – αα / αα) results in a silent carrier, with mild microcytosis. Loss of two α- globin genes on one chromosome (heterozygous αo-Thalassemia; -α -α / α α), or on opposite chromosomes (homozygous α+-Thalassemia; -αα /-αα) may result in a mild microcytic hypochromic anaemia. Loss of three genes(-α -α /-αα) results in an intermediate Thalassemia (Hb H disease), and may be associated with reduced growth rate, iron overload unrelated to transfusion history, and other complications.
دواعي الإستعمال
This test is useful in the investigation of microcytic anemia to prevent erroneous and unnecessary medical intervention for iron deficiency, and the identification of patients of reproductive age who are carriers of serious or life-threatening Hemoglobinopathies. It is highly recommended that α- Thalassemia carrier couples undergo prenatal testing for Thalassemias from amniotic fluid taken in the 2nd trimester of pregnancy since the complete deletion of all 4 α- globin genes (-α -α /-α -α) results in Hemoglobin Bart ; hydrops fetalis, a lethal condition in utero.
نوع العينة والكمية والشروط
EDTA whole blood Amniotic Fluid Room Temperature
إحتياطات خاصة
Collect in EDTA vacutainer tube. Avoid contamination with DNA of phlebotomist. Avoid haemolysed samples. Do not freeze samples. Send tube unopened. 10 ml Amnitic Fluid
المعدل الطبيعي
Negative
