Alpha Thalassemia (4)

The most severe form of alpha thalassemia is Alpha Thalassemia Major or hydrops fetalis, characterized by a deletion of all four genes that code for alpha globins (--/--). This diagnosis is frequently made in the last months of pregnancy when fetal ultrasound indicates a hydropic fetus. The mother frequently exhibits toxemia and can develop severe postpartum hemorrhage. These infants are usually stillborn. There can be other congenital anomalies, though none are pathognomonic for alpha thalassemia major. Since alpha globins are required for production of fetal and adult hemoglobin, the fetus suffers from signifiant in utero hypoxia. The only hemoglobins found in these infants are: Hgb Portland (d²g²), Hgb H (b⁴), and Hgb Bart's (g⁴), and no Hgb A or A₂. These babies can have other complications associated with hydrops, such as heart failure and pulmonary edema.

If the diagnosis is made early, intrauterine transfusions can be performed. There are reports of survival and chronic transfusion in these infants; CHO cares for one alpha thalassemia major baby with chronic transfusion therapy. Undoubtedly, more of these infants could be saved if the diagnosis is anticipated by prenatal diagnosis and treatment provided. <back>

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