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α-globin

Description

21 mutations covering >90% of α-globin defects found in Mediterranean, Middle Eastern and Southeast Asian countries.

– 3.7 Single gene del
– 4.2 Single gene del
– 20.5 kb Double gene del
MED Double gene del
SEA Double gene del
THAI Double gene del
FIL Double gene del
α1 cd 14 G>A
α1 cd 59 G>A
Hb Adana E66

anti-3.7 Gene triplication
α2 init cd [T>C]
α2 cd 19 [-G]
α IVS 1 5nt
α2 cd 59 [G>A]
α2 cd 125 [T>C] (Hb Quong Sze)
α2 cd 142 [T>C] (Hb Constant Spring)
α2 cd 142 [T>A] (Hb Icaria)
α2 cd 142 [A>T] (Hb Pakse)
α2 cd 142 [A>C] (Hb Koya Dora)
α2 poly A-1 [AATAAA>AATAAG]
α2 poly A-1 [AATAAA>AATGAA]

Intended Use

In healthy adults 97-98% of total hemoglobin (Hb) is HbA, consisting of two a-globin and two b-globin polypeptides (a2b2). The a-globin chains are encoded by two highly homologous genes, a1 and a2, which are both embedded in tandem in the a-globin gene cluster on chromosome 16. Reduced or absent a-globin synthesis, mainly caused by deletions of one or both a-globin genes and less frequently by point mutations, leads to a-thalassemia (a-thal). The severity of the a-thal phenotype depends on the number of affected genes and the resulting imbalance between a-and b-globin chains. The loss of one of the two a-globin alleles (-a) causes a+-thal, whereas a0-thal is due to inactivation of both a-globin alleles (–) within a chromosome. Four intact a-globin genes (aa/aa) are present in the diploid genome of a healthy human. Individuals, who inherit only two or three functional genes, have mild anemia and microcytosis. Hb H disease affects subjects with only a single active a-globin gene and presents with moderate to severe hemolytic anemia. The most severe manifestation, the loss of all four a-globin genes (–/–), causes homozygous a0-thal (Hb Bart’s hydrops fetalis syndrome), which is generally associated with death in utero. All these various disorders (hemoglobinopathies) are a major public health problem, particularly in Mediterranean countries, the Middle East, India, Asia and parts of Africa. For the large majority of affected individuals there is only supportive management but no ultimate cure. Health authorities therefore focus on prevention programs based on heterozygous carrier screening and prenatal diagnosis. Since only a few a-globin alleles are prevalent in each at-risk population, large-scale screening programs are feasible, but require simple and automated test procedures.



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Copyright © 2009 - 2019 İnvitrotek A.Ş. All Right Reserved by Invitrotek
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