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Thalassemia
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Alpha
Thalassemia
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Trait
Alpha thalassemia trait.
If both parents carry alpha Thalassemia trait in
which the two abnormal genes of each parent are
on opposite chromosomes, their children will
inherit alpha thalassemia trait.
In this
condition, in which two of the four alpha globin
genes are missing or defective, the lack of
alpha globin protein is somewhat greater. Both
abnormal alpha globin genes may be on the same
chromosome (cis position) or one may be on each
chromosome in the pair (trans position).
Physicians often mistake alpha thalassemia trait
for iron deficiency anemia and incorrectly
prescribe iron supplements that have no effect
on the anemia. Patients with this condition have
smaller red blood cells and a mild anemia,
although they do not experience symptoms.
There is a 25% chance with each pregnancy
that their child will be born with hemoglobin H
disease in which three of the four alpha globin
genes are abnormal. In this condition, the lack
of alpha protein is great enough to cause
moderate to severe anemia and may cause serious
health problems such as an enlarged spleen, bone
deformities and fatigue.
There is a 25% chance with each pregnancy that
their child will inherit hydrops fetalis or
alpha thalassemia major, in which all four alpha
globin genes are abnormal. Most individuals with
this condition die before or shortly after
birth. In some extremely rare cases, in utero
blood transfusions have allowed the birth of
children with hydrops fetalis who then require
lifelong blood transfusions and extensive
ongoing medical care.
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Thalassemia
