ALPHA-THALASSEMIA CAUSED BY A 16 BP DELETION IN THE 3'-UNTRANSLATED REGION OF THE ALPHA-2-GLOBIN GENE INCLUDING THE FIRST NUCLEOTIDE OF THEPOLY-A SIGNAL SEQUENCE

We have identified a 16 bp deletion in the 3' untranslated region of t he alpha 2-globin gene, inducting the first nucleotide of the polyaden ylation signal sequence. The propositus, her mother and one of her bro thers, all heterozygotes for the above deletion, have mild microcytic anemia. This is the first description of a deletion in the alpha gene involving both the 3' untranslated region and the polyadenylation sign al sequence, causing alpha-thalassemia.