Homozygous a-thalassemia (--/--) has what clinical outcome?

a. Incompatible with life
b. Severe anemia
c. Mild anemia
d. No anemia


ANS: A
When all four a genes are missing, no a globin chains are synthesized. All normal hemoglobins (A, A2, and F) require a chains. In utero, the predominant hemoglobin will be Hb Barts (g4). This is a high oxygen affinity hemoglobin and thus is not effective in reversible oxygen transport. There will also be some Hb Portland (z2g2) and traces of Hb H (b4). Hb Portland is the primary hemoglobin up until the third trimester of fetal life, so the fetus generally survives until the third trimester.

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Answer the following statement true (T) or false (F)

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ex-

What will be an ideal response?

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