A newly-characterized α-thalassaemia-1 deletion removes the entire α-like globin gene cluster in an Italian family

We describe a new deletional form of α thalassaemia which encompasses the entire α-like globin gene cluster in a 15-year-old boy of Southern Italian descent. The deletion removes ~ 31 kb, the 5'-end point is located approximately 4 kb upstream of the ξ gene, while the 3'-end point maps between the α₁- and Θ₁-globin genes. The interaction of this deletion with the common-α^3.7 form gives origin to a classical form of haemoglobin (Hb) H disease in the propositus of this study. Deletional forms of ξα-thalassaemia are uncommon in the Mediterranean basin; as for other unusual ξα-thalassaemia forms, heterozygotes for this mutation may escape detection in population surveys based on ξ and α probes.