β-Globin gene inactivation by DNA translocation in γβ-thalassaemi

Abstract
The .beta.-globin gene present on the deletion locus in a Dutch .gamma..beta.-thalassemic patient was identical to the normal .beta.-globin gene with respect to DNA sequence and its transcription in [human cervical carcinoma] HeLa cells. DNase I sensitivity and methylation experiments show that the affected .beta.-globin gene is present in an inactive configuration in vivo. This is the result of a translocation of a normally inactive locus next to the .beta.-globin gene on the affected chromosome, or the deletion of sequences which are normally required for the maintenance of the active state.