High frequency of deletional alpha-thalassemia in beta-thalassemia trait: implications for genetic counseling

Thalassemias are a group of genetic hemolytic disorders with varying phenotypes. In this study, the frequency of alpha globin gene deletions was studied in the beta-thalassemia trait, the mildest form of the disorder. Eleven out of 33 (33%) individuals were positive for alpha(-3.7 kb) deletions. None of the subjects was positive for the Southeast Asian deletion. Such a high frequency for alpha deletions has not been reported earlier in thalassemia minor. Hematological parameters are compared, and implications of this finding for genetic counseling are discussed.