Treatment of alpha(0)-thalassemia (--(SEA)/--(SEA)) via serial fetal and post-natal transfusions: Can early fetal intervention improve outcomes?

Abstract

Objective and importance: Homozygous Southeast Asian alpha-thalassemia mutation (--(SEA)/--(SEA)) results in deletion of all alpha-globin genes (alpha(0)-thalassemia). Since all alpha-globin chains are absent, hemoglobin F cannot be synthesized, and hemoglobin Bart's becomes the dominant fetal hemoglobin. Hemoglobin Bart's is a γ tetramer with a very high oxygen affinity, thus oxygen delivery to the tissues is poor. Clinical manifestations include severe fetal anemia, hydrops fetalis, fetal demise, and high risk of neurodevelopmental impairment in the rare survivors.

Clinical presentation: A 39-year-old Vietnamese woman presented to our center at 28 0/7 weeks' gestation with fetal alpha(0)-thalassemia (--(SEA)/--(SEA) type deletion) and ultrasound markers suggestive of severe fetal anemia.

Intervention: The fetus was treated with four intrauterine transfusions followed by post-natal chronic transfusions. Formal neurodevelopmental testing (Battelle Developmental Inventory, Second Edition) was performed at 18 months of age, and the developmental quotient was 93 (32nd percentile) with all subdomains noted within normal limits, indicating overall intact neurodevelopment.

Conclusion: We posit that earlier diagnosis and fetal treatment, prior to clinical findings suggestive of fetal anemia, may improve long-term outcomes by enhancing oxygen delivery to the tissues of the developing fetus.

Keywords: Bart's hemoglobinopathy; Homozygous alpha-thalassemia; Hydrops fetalis; Intrauterine transfusion.