α-thalassemia caused by a large (62 kb) deletion upstream of the human α globin gene cluster

Abstract

We describe a family in which αthalassemia occurs in association with a deletion of 62 kilobases from a region upstream of the α globin genes. DNA sequence analysis has shown that the transcription units of both a genes down-stream of this deletion are normal. Nevertheless, they fail to direct α globin synthesis in an interspecific hybrid containing the abnormal (αα)α chromosome. It seems probable that previously unidentified positive regulatory sequences analogous to those detected in a corresponding position of the human β globin cluster are removed by this deletion. © 1990 by The American Society of Hematology.