The distinguishing feature of both alpha thalassemia-one-trait and alpha thalassemia-two-trait conditions compared to Bart's hydrops fetalis or hemoglobin H disease is:

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Quizplus · Accepted Answer

In alpha thalassemia-one-trait and alpha thalassemia-two-trait conditions, there is a lack of production of one or two of the four alpha-globin chains, respectively. This results in a decreased production of adult hemoglobin, but there is still some production of fetal hemoglobin, which can persist into adulthood in low levels. However, hemoglobin Bart's and hemoglobin H disease are more severe forms of alpha thalassemia, in which there is a complete absence (Bart's) or severe deficiency (H disease) of alpha-globin chains, leading to the persistence of fetal hemoglobin and hemoglobin Portland (a type of hemoglobin found only in fetuses) at birth, but there is no disappearance of hemoglobin Bart's or Portland with development.

The Distinguishing Feature of Both Alpha Thalassemia-One-Trait and Alpha Thalassemia-Two-Trait