Variable clinical phenotypes of alpha-thalassemia syndromes.

Genetic mutations of the alpha genes are common worldwide. In Asia and particularly Southeast Asia, they can result in clinically significant types of alpha-thalassemia, namely hemoglobin (Hb) H disease and Hb Bart's hydrops fetalis. The latter is generally a fatal intrauterine condition, while Hb H disease results in clinical complications that are frequently overlooked. The high prevalence of the carrier state and the burden of these diseases (and other alpha-thalassemia variants) call for more attention for improved screening methods and better care.