Characterization of a novel deletion causing (δβ) 0 ‐thalassemia in a Thai family

A novel deletion of the human β‐globin gene cluster associated with the increased level of fetal hemoglobin (Hb F) in adult life has been demonstrated in a Thai family. A Thai girl who was mistakenly diagnosed as β‐thalassemia/HbE is found to be the compound heterozygote of this mutation and Hb E. The heterozygous father had mild hypochromic and microcytic red blood cells and a high level of Hb F (23.2%). Polymorphic restriction sites in the β‐globin gene cluster identified the homozygous alleles, which localized the deletion region between the ψβ‐globin and the 3′ β‐globin genes. DNA polymerase that can amplify a long DNA template was employed to examine DNA fragment encompassing this deletion. A 11.3 kilobases (kb) of DNA deletion, beginning ∼3.1 kb 5′ to the δ‐globin gene and end in the intron 2 of the β‐globin gene was detected. DNA analysis revealed that this is a case of (δβ) 0 ‐thalassemia with a novel mutation, which can lead to a mild form of β‐thalassemia upon interaction with Hb E. Am. J. Hematol., 2006. © 2006 Wiley‐Liss, Inc.