Diagnosis of<unk>  is primarily by laboratory evaluation and molecular diagnosis.<unk>  can be mistaken for iron-deficiency anaemia on a full blood count or blood film, as both conditions have a microcytic anaemia. Serum iron and serum ferritin can be used to exclude iron-deficiency anaemia. Types Two genetic loci exist for α globin, thus four alleles are in diploid cells. Two alleles are maternal and two alleles are paternal in origin. The severity of the<unk> assemias is correlated with the number of affected α-globin alleles: the greater, the more severe will be the manifestations of the disease. When noting the genotype, an "α" indicates a functional<unk>  chain, and '-' a pathological one. Alleles affected Description Genotype One This is known as<unk>  silent and with this type, the effect on hemoglobin synthesis is minimal. Three α-globin genes are enough to permit normal hemoglobin production, and no clinical symptoms present. It occurs due to a deletion or non-deletion mutation. - α/α α Two Haematopoiesis(production of blood cells) The condition is called<unk>  trait; two α genes permit nearly normal production of red blood cells, but a mild microcytic hypochromic anemia is seen. The disease in this form can be mistaken for iron-deficiency anemia and treated inappropriately with iron.<unk>  trait can exist in two forms: *<unk> -1 (- -/α α), involves cis deletion of both<unk>  genes on the same chromosome. Higher incidence in people of Asian descent when compared with the general population. *<unk> -2 (- α/- α), involves trans deletion of<unk>  genes; this occurs on different (homologous) chromosomes. Higher incidence in people of African descent when compared with the general population. - -/α α or- α/- α Three This condition is called hemoglobin H disease; two unstable hemoglobins are present in the blood; hemoglobin Barts (tetrameric γ chains) and hemoglobin H (tetrameric β chains). Both of these unstable hemoglobins have a higher affinity for oxygen than normal hemoglobin. A microcytic hypochromic anemia with target cells and Heinz bodies (precipitated HbH) on the peripheral blood smear can occur, as well as hepatosplenomegaly. The disease is noticed in childhood or in early adult life; anemia and hepatosplenomegaly are noted. - -/- α Four This is known as<unk>  major; these fetuses are edematous, have little circulating hemoglobin, and the hemoglobin that is present is all tetrameric γ chains. When all four alleles are affected, the fetus likely will not survive gestation without in utero intervention; most infants with<unk>  major are stillborn with hydrops fetalis. Fetuses treated with intrauterine transfusions throughout pregnancy starting at an early gestational age can survive to birth with acceptable morbidity. After birth, the treatment options include bone marrow transplantation or continued chronic transfusions. - -/- - α α/α α = normal: 'α α' before the '/' represents one chromosome, and 'α α' after the '/', its homologous chromosome. Laboratory diagnosis The ability to measure hemoglobin Barts makes it useful in newborn screening tests. If hemoglobin Barts is detected on a newborn screen, the patient is usually referred for further evaluation since detection of hemoglobin Barts can indicate either one<unk>  globin gene deletion, making the baby a silent<unk>  carrier, two<unk>  globin gene deletions <unk> , or hemoglobin H disease (three<unk>  globin gene deletions). Deletion of four<unk>  globin genes was previously felt to be incompatible with life, but there are currently 69 patients who have survived past infancy. All such children too show high level of hemoglobin Barts on newborn screen along with other variants. Post-newborn ages, initial laboratory diagnosis should include a complete blood count and red blood cell indices. As well, a peripheral blood smear should be carefully reviewed. In hemoglobin H disease, red blood cells containing hemoglobin H inclusions can be visualized on the blood smear using new methylene blue or brilliant cresyl blue stain. Hemoglobin analysis is important for the diagnosis of<unk>  as it determines the types and percentages of types of hemoglobin present. Several different methods of hemoglobin analysis exist, including hemoglobin electrophoresis, capillary electrophoresis and high-performance liquid chromatography. Molecular analysis of DNA sequences (DNA analysis) can be used for the confirmation of a diagnosis of<unk> , particularly for the detection of<unk>  carriers (deletions or mutations in only one or two<unk> -globin genes).
Alpha-thalassemia
Thalassemia
Beta thalassemia
Delta-beta thalassemia
Hereditary spherocytosis
Hemoglobinemia
Paroxysmal nocturnal hemoglobinuria
Sideroblastic anemia